IBD — MCQs

Q: A 17-year-old girl is brought to the physician by her parents for the evaluation of belly pain and a pruritic skin rash on her shoulders for the last 6 months. She describes feeling bloated after meals. Over the past 3 months, she has had multiple loose bowel movements per day. She appears thin. She is at the 20th percentile for height and 8th percentile for weight. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 16/min, and blood pressure is 120/78 mm Hg. Examination shows conjunctival pallor and inflammation of the corners of the mouth. There are several tense, grouped subepidermal blisters on the shoulders bilaterally. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Further evaluation of this patient is most likely to show which of the following findings?

IgA tissue transglutaminase antibodies. ***IgA tissue transglutaminase antibodies*** - The patient's symptoms of **belly pain**, **bloating**, **loose bowel movements**, **weight loss**, **growth failure** (low height and weight percentiles), and **pruritic skin rash** (dermatitis herpetiformis) are highly suggestive of **celiac disease**. - **IgA tissue transglutaminase (tTG) antibodies** are the most sensitive and specific serological test for celiac disease. *Increased serum lipase* - **Increased serum lipase** is indicative of **pancreatitis**, which is not supported by the patient's symptoms or physical findings. - While chronic pancreatitis can cause malabsorption, the characteristic skin rash and other gastrointestinal symptoms do not point to this diagnosis. *Oocysts on acid-fast stain* - **Oocysts on acid-fast stain** are used to diagnose **cryptosporidiosis** or other parasitic infections, which can cause chronic diarrhea but typically do not present with a characteristic skin rash like dermatitis herpetiformis. - The presentation is more consistent with an autoimmune enteropathy rather than an infectious cause. *Inflammation of the terminal ileum* - **Inflammation of the terminal ileum** is characteristic of **Crohn's disease**, which can cause abdominal pain, diarrhea, and weight loss. - However, the pruritic, blistering rash on the shoulders (dermatitis herpetiformis) is a hallmark of **celiac disease** and not typical for Crohn's disease. *Esophageal webs* - **Esophageal webs** are associated with **Plummer-Vinson syndrome**, which causes dysphagia and iron deficiency anemia. - While this patient shows signs of anemia (conjunctival pallor), esophageal webs do not explain the chronic diarrhea, bloating, or the characteristic skin rash.

Q: A 25-year-old woman presents to the emergency department with fatigue and weakness. She states over the past 24 hours she has not felt like herself and has felt like she has no strength. The patient has no significant past medical history other than a single episode of blood-tinged diarrhea 1 week ago which resolved on its own. Her temperature is 99.4°F (37.4°C), blood pressure is 124/62 mmHg, pulse is 95/min, respirations are 29/min, and oxygen saturation is 95% on room air. Physical exam is notable for 2/5 strength of the lower extremities and decreased sensation in the lower extremities and finger tips. Which of the following is the best initial step in management?

Spirometry. ***Spirometry*** - The patient's symptoms (fatigue, weakness, decreased strength, and sensation in extremities) following a gastrointestinal infection are highly suggestive of **Guillain-Barré Syndrome (GBS)**. - **Spirometry** is the most critical initial step to assess respiratory function, as **respiratory muscle weakness** is the primary cause of morbidity and mortality in GBS. *IV immunoglobulin* - While **intravenous immunoglobulin (IVIG)** is a treatment for GBS, it is not the *initial* management step. - The immediate priority in suspected GBS is to assess and stabilize the patient's respiratory status, not to initiate definitive treatment. *Dexamethasone* - **Corticosteroids** like dexamethasone have **not been shown to be effective** in treating GBS and may even prolong recovery in some cases. - Their use is generally avoided in the management of GBS. *Intubation* - **Intubation** is indicated if spirometry reveals rapidly declining or severely compromised respiratory function, but it is not the *initial* step. - An assessment of respiratory capacity via spirometry should precede intubation unless acute respiratory failure is immediately apparent. *Pyridostigmine* - **Pyridostigmine** is an anticholinesterase inhibitor used primarily for the symptomatic treatment of **myasthenia gravis**. - It is not indicated for the management of GBS, which involves a different pathophysiological mechanism.

Q: A 19-year-old woman comes to the physician because of a 1-year history of severe abdominal pain, bloating, and episodic diarrhea. She also has a 10-kg (22-lb) weight loss over the past 10 months. Physical examination shows a mildly distended abdomen, diffuse abdominal tenderness, and multiple erythematous, tender nodules on the anterior aspect of both legs. There is a small draining lesion in the perianal region. Further evaluation of this patient's gastrointestinal tract is most likely to show which of the following findings?

Transmural inflammation. **Transmural inflammation** - The patient's symptoms (abdominal pain, bloating, diarrhea, weight loss) and extraintestinal manifestations (erythematous nodules, perianal lesion) are classic for **Crohn's disease**. - A hallmark pathological feature of Crohn's disease is **transmural inflammation**, affecting all layers of the bowel wall, which can lead to complications like strictures, fistulas, and abscesses. *Melanosis coli* - This is a harmless condition characterized by **pigmentation of the colonic mucosa** due to chronic laxative use, particularly **anthraquinone laxatives**. - It is not associated with inflammatory bowel disease or the systemic symptoms described. *Villous atrophy* - **Villous atrophy** is the flattening of the villi in the small intestine, most commonly seen in **celiac disease**. - While celiac disease can cause malabsorption and gastrointestinal symptoms, the extraintestinal manifestations and perianal draining lesion are inconsistent with celiac disease. *Crypt abscesses* - **Crypt abscesses** are a characteristic histological finding in **ulcerative colitis**, which primarily affects the colon and rectum. - While ulcerative colitis, like Crohn's, is an inflammatory bowel disease, the presence of transmural inflammation and perianal disease (fistulas/draining lesions) is more indicative of Crohn's. *No structural abnormalities* - The severe symptoms, significant weight loss, and presence of extraintestinal manifestations (erythema nodosum, perianal disease) strongly suggest an underlying structural and inflammatory pathology in the GI tract. - **Irritable Bowel Syndrome (IBS)** typically presents with similar symptoms but lacks structural abnormalities and the systemic inflammatory signs seen here.

Q: A 37-year-old man with Crohn disease is admitted to the hospital because of acute small bowel obstruction. Endoscopy shows a stricture in the terminal ileum. The ileum is surgically resected after endoscopic balloon dilatation fails to relieve the obstruction. Three years later, he returns for a follow-up examination. He takes no medications. This patient is most likely to have which of the following physical exam findings?

Weakness and ataxia. ***Weakness and ataxia*** - This patient with a history of **Crohn disease** and significant **ileal resection** is at high risk for **vitamin B12 deficiency** due to the removal of the primary site of absorption in the terminal ileum. - **Vitamin B12 deficiency** can lead to subacute combined degeneration of the spinal cord, manifesting as **weakness**, **ataxia**, and **paresthesias**. *Dry skin and keratomalacia* - This presentation is indicative of **vitamin A deficiency**, which can occur in malabsorption but is less specific to ileal resection than B12 deficiency. - While fat-soluble vitamins (A, D, E, K) are absorbed in the small intestine, severe isolated vitamin A deficiency causing keratomalacia is not the most likely primary finding after ileal resection. *Hyperreflexia with tetany* - These symptoms typically suggest **hypocalcemia** or **hypomagnesemia**, often due to vitamin D deficiency or malabsorption of minerals. - Although possible with generalized malabsorption, it is not the most characteristic neurological complication following isolated ileal resection compared to vitamin B12 deficiency. *Gingival swelling and bleeding* - This is a hallmark of **scurvy**, caused by **vitamin C deficiency**, which is typically absorbed in the small intestine and does not correlate specifically with ileal resection. - This would be a less likely complication given the specific history compared to micronutrient deficiencies related to terminal ileum function. *Pallor with koilonychia* - **Pallor** and **koilonychia (spoon nails)** are characteristic signs of **iron deficiency anemia**. - While iron is absorbed in the duodenum and proximal jejunum, and anemia is common in Crohn disease, the specific neurological symptoms from B12 deficiency are generally more prominent after ileal resection.

Q: A 47-year-old man presents to his primary care physician complaining of pain and stiffness in his right index finger and left knee. The past medical history is remarkable for severe dandruff and an episode of apparent gout in the left 1st toe 6 months ago, which never resolved. The physical examination confirms dactylitis of the right index finger and several toes, as well as synovitis of the left knee. He is also noted to have pitting of his fingernails. Plain X-rays of his hand reveal erosions in the distal interphalangeal (DIP) joint and periarticular new bone formation. Which of the following is most consistent with these findings?

Psoriatic arthritis. ***Psoriatic arthritis*** - The constellation of **dactylitis**, **nail pitting**, involvement of both **DIP joints** with erosions, and a history of **psoriasis** (severe dandruff) is highly characteristic of psoriatic arthritis. - The previous episode resembling gout and synovitis of the knee are also consistent, as psoriatic arthritis can mimic other arthropathies and affect various joints. *Pseudogout* - This condition is caused by **calcium pyrophosphate dihydrate crystal deposition** and typically presents as acute, severe joint pain, often in larger joints like the knee or wrist, but without dermatological or nail changes. - While it can cause synovitis, it does not typically involve dactylitis, DIP erosions, nail pitting, or a history of psoriasis. *Osteoarthritis* - Characterized by **cartilage degeneration** and **new bone formation** (osteophytes), often in weight-bearing joints or DIP/PIP joints, but typically without the marked inflammatory signs like dactylitis or nail changes. - While X-rays can show new bone formation, the presence of dactylitis, nail pitting, and psoriasis history rule out uncomplicated osteoarthritis. *Reactive arthritis* - This is an **acute, inflammatory arthropathy** that typically develops after a genitourinary or gastrointestinal infection. - While it can present with dactylitis and oligoarthritis, it does not involve nail pitting or a history of psoriasis, and the initial trigger infection is usually identifiable. *Rheumatoid arthritis* - This is a **chronic autoimmune disease** primarily affecting smaller joints symmetrically, particularly the MCP and PIP joints, but typically sparing the DIP joints. - It is not associated with psoriasis, nail pitting, and usually presents with periarticular osteopenia rather than significant new bone formation on X-ray.

Q: A 61-year-old man comes to the physician because of fatigue, diarrhea, and crampy abdominal pain for 3 weeks. The abdominal pain is worse after eating. During the past week, he has had up to 4 watery stools daily. He has also had pain in his mouth and gums for 6 days. He has not had nausea, vomiting, or fever. Four months ago, he went on a 1-week trip to the Dominican Republic. He has atrial fibrillation, hypertension, and hypothyroidism. Current medications include levothyroxine, metoprolol, and warfarin. He has smoked one pack of cigarettes daily for 40 years. His temperature is 37.9°C (100.2°F), pulse is 81/min, and blood pressure is 120/75 mm Hg. Examination shows two 1-cm, tender ulcerative lesions in the mouth. Abdominal examination shows mild tenderness to palpation in the right lower quadrant without guarding or rebound. Bowel sounds are normal. His hemoglobin concentration is 11.5 g/dL, mean corpuscular volume is 77 fL, leukocyte count is 11,800/mm³, and platelet count is 360,000/mm³. Colonoscopy with biopsy of the colonic mucosa is performed. Analysis of the specimen shows non-caseating granulomas and neutrophilic inflammation of the crypts. Which of the following is the most likely diagnosis?

Crohn disease. ***Crohn disease*** - The presence of **fatigue, diarrhea, crampy abdominal pain worse after eating, oral ulcers, and mild right lower quadrant tenderness** is highly suggestive of Crohn disease. - The colonoscopy finding of **non-caseating granulomas** with **neutrophilic inflammation of the crypts** is a classic histopathological hallmark of Crohn disease. *Diverticulitis* - Typically presents with **left lower quadrant pain**, fever, and leukocytosis, usually without oral lesions or chronic diarrhea. - Histopathology would show **inflammation of diverticula**, not non-caseating granulomas. *Whipple disease* - Characterized by **malabsorption, arthralgias, neurological symptoms, and lymphadenopathy,** caused by *Tropheryma whipplei*. - Biopsy would reveal **PAS-positive macrophages** with bacilliform bodies, not non-caseating granulomas or neutrophilic crypt inflammation. *Celiac disease* - Triggered by **gluten ingestion**, leading to malabsorption, diarrhea, and abdominal pain, but often associated with **iron deficiency anemia** and weight loss. - Diagnosis is made by biopsy showing **villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes**, not granulomas. *Tropical sprue* - A chronic diarrheal illness defined by **malabsorption** in individuals residing in or visiting tropical regions, often leading to **folate or B12 deficiency**. - Biopsy findings include **partial villous atrophy and inflammatory cell infiltration** of the lamina propria, distinct from granulomas.

A 17-year-old girl is brought to the physician by her parents for the evaluation of belly pain and a pruritic skin rash on her shoulders for the last 6 months. She describes feeling bloated after meals. Over the past 3 months, she has had multiple loose bowel movements per day. She appears thin. She is at the 20th percentile for height and 8th percentile for weight. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 16/min, and blood pressure is 120/78 mm Hg. Examination shows conjunctival pallor and inflammation of the corners of the mouth. There are several tense, grouped subepidermal blisters on the shoulders bilaterally. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Further evaluation of this patient is most likely to show which of the following findings?

A 32-year-old man with Crohn disease is brought to the emergency department after he fainted at work. He says that he has been feeling increasingly fatigued and weak over the last several weeks though he has not previously had any episodes of syncope. On presentation he is found to be pale and agitated. A panel of lab tests is performed showing the following: Hemoglobin: 10.2 g/dL Hematocrit: 30.1% Leukocyte count: 9,900 cells/mm^3 with normal differential Platelet count: 290,000/mm^3 Mean corpuscular volume: 118 µm^3 Elevated homocysteine level Normal methylmalonic acid level Which of the following mechanisms explains how Crohn disease may have contributed to this patient's symptoms?

A 33-year-old man has a history of intermittent bloody diarrhea, tenesmus, fever, fatigue, and lower abdominal cramps for the past 2 weeks. On physical examination, he is lethargic and appears lean and pale. He has aphthous stomatitis, red congested conjunctiva, and tender swollen joints. At the doctor’s office, his pulse is 114/min, blood pressure is 102/76 mm Hg, respirations are 20/min, and his temperature is 39.4°C (102.9°F). There is vague lower abdominal tenderness and frank blood on rectal examination. Laboratory studies show: Hemoglobin 7.6 g/dL Hematocrit 33% Total leucocyte count 22,000/mm3 Stool assay for C.difficile is negative Abdominal X-ray shows no significant abnormality He is symptomatically managed and referred to a gastroenterologist, who suggests a colonoscopy and contrast (barium) study for the diagnosis. Which of the following is the most likely combination of findings in his colonoscopy and barium study?

A 31-year-old woman comes to the emergency department because of a 4-day history of fever and diarrhea. She has abdominal cramps and frequent bowel movements of small quantities of stool with blood and mucus. She has had multiple similar episodes over the past 8 months. Her temperature is 38.1°C (100.6°F), pulse is 75/min, and blood pressure is 130/80 mm Hg. Bowel sounds are normal. The abdomen is soft. There is tenderness to palpation in the left lower quadrant with guarding and no rebound. She receives appropriate treatment and recovers. Two weeks later, colonoscopy shows polypoid growths flanked by linear ulcers. A colonic biopsy specimen shows mucosal edema with distorted crypts and inflammatory cells in the lamina propria. Which of the following is the most appropriate recommendation for this patient?

A 25-year-old woman presents to the emergency department with fatigue and weakness. She states over the past 24 hours she has not felt like herself and has felt like she has no strength. The patient has no significant past medical history other than a single episode of blood-tinged diarrhea 1 week ago which resolved on its own. Her temperature is 99.4°F (37.4°C), blood pressure is 124/62 mmHg, pulse is 95/min, respirations are 29/min, and oxygen saturation is 95% on room air. Physical exam is notable for 2/5 strength of the lower extremities and decreased sensation in the lower extremities and finger tips. Which of the following is the best initial step in management?

A 19-year-old woman comes to the physician because of a 1-year history of severe abdominal pain, bloating, and episodic diarrhea. She also has a 10-kg (22-lb) weight loss over the past 10 months. Physical examination shows a mildly distended abdomen, diffuse abdominal tenderness, and multiple erythematous, tender nodules on the anterior aspect of both legs. There is a small draining lesion in the perianal region. Further evaluation of this patient's gastrointestinal tract is most likely to show which of the following findings?

A 37-year-old man with Crohn disease is admitted to the hospital because of acute small bowel obstruction. Endoscopy shows a stricture in the terminal ileum. The ileum is surgically resected after endoscopic balloon dilatation fails to relieve the obstruction. Three years later, he returns for a follow-up examination. He takes no medications. This patient is most likely to have which of the following physical exam findings?

A 47-year-old man presents to his primary care physician complaining of pain and stiffness in his right index finger and left knee. The past medical history is remarkable for severe dandruff and an episode of apparent gout in the left 1st toe 6 months ago, which never resolved. The physical examination confirms dactylitis of the right index finger and several toes, as well as synovitis of the left knee. He is also noted to have pitting of his fingernails. Plain X-rays of his hand reveal erosions in the distal interphalangeal (DIP) joint and periarticular new bone formation. Which of the following is most consistent with these findings?

A 61-year-old man comes to the physician because of fatigue, diarrhea, and crampy abdominal pain for 3 weeks. The abdominal pain is worse after eating. During the past week, he has had up to 4 watery stools daily. He has also had pain in his mouth and gums for 6 days. He has not had nausea, vomiting, or fever. Four months ago, he went on a 1-week trip to the Dominican Republic. He has atrial fibrillation, hypertension, and hypothyroidism. Current medications include levothyroxine, metoprolol, and warfarin. He has smoked one pack of cigarettes daily for 40 years. His temperature is 37.9°C (100.2°F), pulse is 81/min, and blood pressure is 120/75 mm Hg. Examination shows two 1-cm, tender ulcerative lesions in the mouth. Abdominal examination shows mild tenderness to palpation in the right lower quadrant without guarding or rebound. Bowel sounds are normal. His hemoglobin concentration is 11.5 g/dL, mean corpuscular volume is 77 fL, leukocyte count is 11,800/mm³, and platelet count is 360,000/mm³. Colonoscopy with biopsy of the colonic mucosa is performed. Analysis of the specimen shows non-caseating granulomas and neutrophilic inflammation of the crypts. Which of the following is the most likely diagnosis?

Q10

A 25-year-old man presents to the emergency department for severe abdominal pain. The patient states that for the past week he has felt fatigued and had a fever. He states that he has had crampy lower abdominal pain and has experienced several bouts of diarrhea. The patient states that his pain is somewhat relieved by defecation. The patient returned from a camping trip 2 weeks ago in the Rocky Mountains. He is concerned that consuming undercooked meats on his trip may have caused this. He admits to consuming beef and chicken cooked over a fire pit. The patient is started on IV fluids and morphine. His temperature is 99.5°F (37.5°C), blood pressure is 130/77 mmHg, pulse is 90/min, respirations are 12/min, and oxygen saturation is 98% on room air. Laboratory studies are ordered and are seen below. Hemoglobin: 10 g/dL Hematocrit: 28% Leukocyte count: 11,500 cells/mm^3 with normal differential Platelet count: 445,000/mm^3 Serum: Na+: 140 mEq/L Cl-: 102 mEq/L K+: 4.1 mEq/L HCO3-: 24 mEq/L BUN: 24 mg/dL Glucose: 145 mg/dL Creatinine: 1.4 mg/dL Ca2+: 9.6 mg/dL Erythrocyte sedimentation rate (ESR): 75 mm/hour Physical exam is notable for a patient who appears to be uncomfortable. Gastrointestinal (GI) exam is notable for abdominal pain upon palpation. Ear, nose, and throat exam is notable for multiple painful shallow ulcers in the patient's mouth. Inspection of the patient's lower extremities reveals a pruritic ring-like lesion. Cardiac and pulmonary exams are within normal limits. Which of the following best describes this patient's underlying condition?

IBD US Medical PG Practice Questions and MCQs

Question 1: A 17-year-old girl is brought to the physician by her parents for the evaluation of belly pain and a pruritic skin rash on her shoulders for the last 6 months. She describes feeling bloated after meals. Over the past 3 months, she has had multiple loose bowel movements per day. She appears thin. She is at the 20th percentile for height and 8th percentile for weight. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 16/min, and blood pressure is 120/78 mm Hg. Examination shows conjunctival pallor and inflammation of the corners of the mouth. There are several tense, grouped subepidermal blisters on the shoulders bilaterally. The abdomen is soft, and there is diffuse tenderness to palpation with no guarding or rebound. Further evaluation of this patient is most likely to show which of the following findings?

A. Increased serum lipase
B. IgA tissue transglutaminase antibodies (Correct Answer)
C. Oocysts on acid-fast stain
D. Inflammation of the terminal ileum
E. Esophageal webs

Explanation: ***IgA tissue transglutaminase antibodies*** - The patient's symptoms of **belly pain**, **bloating**, **loose bowel movements**, **weight loss**, **growth failure** (low height and weight percentiles), and **pruritic skin rash** (dermatitis herpetiformis) are highly suggestive of **celiac disease**. - **IgA tissue transglutaminase (tTG) antibodies** are the most sensitive and specific serological test for celiac disease. *Increased serum lipase* - **Increased serum lipase** is indicative of **pancreatitis**, which is not supported by the patient's symptoms or physical findings. - While chronic pancreatitis can cause malabsorption, the characteristic skin rash and other gastrointestinal symptoms do not point to this diagnosis. *Oocysts on acid-fast stain* - **Oocysts on acid-fast stain** are used to diagnose **cryptosporidiosis** or other parasitic infections, which can cause chronic diarrhea but typically do not present with a characteristic skin rash like dermatitis herpetiformis. - The presentation is more consistent with an autoimmune enteropathy rather than an infectious cause. *Inflammation of the terminal ileum* - **Inflammation of the terminal ileum** is characteristic of **Crohn's disease**, which can cause abdominal pain, diarrhea, and weight loss. - However, the pruritic, blistering rash on the shoulders (dermatitis herpetiformis) is a hallmark of **celiac disease** and not typical for Crohn's disease. *Esophageal webs* - **Esophageal webs** are associated with **Plummer-Vinson syndrome**, which causes dysphagia and iron deficiency anemia. - While this patient shows signs of anemia (conjunctival pallor), esophageal webs do not explain the chronic diarrhea, bloating, or the characteristic skin rash.

Question 2: A 32-year-old man with Crohn disease is brought to the emergency department after he fainted at work. He says that he has been feeling increasingly fatigued and weak over the last several weeks though he has not previously had any episodes of syncope. On presentation he is found to be pale and agitated. A panel of lab tests is performed showing the following: Hemoglobin: 10.2 g/dL Hematocrit: 30.1% Leukocyte count: 9,900 cells/mm^3 with normal differential Platelet count: 290,000/mm^3 Mean corpuscular volume: 118 µm^3 Elevated homocysteine level Normal methylmalonic acid level Which of the following mechanisms explains how Crohn disease may have contributed to this patient's symptoms?

A. Gastrointestinal blood loss
B. Inflammation of the ileum
C. Inflammation of the jejunum (Correct Answer)
D. Release of acute phase proteins
E. Inflammation of the duodenum

Explanation: ***Inflammation of the jejunum*** - The patient's **macrocytic anemia** (MCV 118 fL) with **elevated homocysteine** and **normal methylmalonic acid** points to a **folate deficiency**. - **Folate** is primarily absorbed in the **proximal small intestine**, particularly the **jejunum**; inflammation in this segment due to Crohn's disease would impair its absorption, leading to deficiency. - While Crohn's disease classically affects the **terminal ileum**, it can involve any part of the GI tract, and **jejunal involvement** would specifically impair folate absorption. *Gastrointestinal blood loss* - Chronic gastrointestinal blood loss typically causes **microcytic anemia** due to iron deficiency, not the macrocytic anemia seen here. - While Crohn's can cause bleeding, the **elevated homocysteine with normal methylmalonic acid** is specific for **folate deficiency**, not blood loss. *Inflammation of the ileum* - **Ileal inflammation** is the most common location in Crohn disease and primarily affects the absorption of **vitamin B12** and **bile salts**. - **Vitamin B12 deficiency** would cause elevated **both homocysteine and methylmalonic acid** levels, which contradicts the normal methylmalonic acid observed in this patient. *Release of acute phase proteins* - **Acute phase proteins** are markers of inflammation and contribute to **anemia of chronic disease**, which is typically **normocytic** or mildly **microcytic**. - This mechanism does not explain the **macrocytic anemia** with the specific biochemical pattern of elevated homocysteine and normal methylmalonic acid, which indicates **folate deficiency**. *Inflammation of the duodenum* - The **duodenum** is the primary site for **iron absorption**, though it also participates in **folate absorption** along with the jejunum. - However, inflammation here would more likely lead to **iron deficiency anemia** (microcytic), and duodenal involvement is **less common** in Crohn disease compared to terminal ileal or jejunal disease. - The clinical picture is most consistent with **jejunal inflammation** causing isolated folate malabsorption.

Question 3: A 33-year-old man has a history of intermittent bloody diarrhea, tenesmus, fever, fatigue, and lower abdominal cramps for the past 2 weeks. On physical examination, he is lethargic and appears lean and pale. He has aphthous stomatitis, red congested conjunctiva, and tender swollen joints. At the doctor’s office, his pulse is 114/min, blood pressure is 102/76 mm Hg, respirations are 20/min, and his temperature is 39.4°C (102.9°F). There is vague lower abdominal tenderness and frank blood on rectal examination. Laboratory studies show: Hemoglobin 7.6 g/dL Hematocrit 33% Total leucocyte count 22,000/mm3 Stool assay for C.difficile is negative Abdominal X-ray shows no significant abnormality He is symptomatically managed and referred to a gastroenterologist, who suggests a colonoscopy and contrast (barium) study for the diagnosis. Which of the following is the most likely combination of findings in his colonoscopy and barium study?

A. Colonoscopy: Multiple vascular malformations that resemble telangiectasias on the colon wall, Barium study: Normal
B. Colonoscopy: Patches of mucosal erosions with pseudomembrane formation, Barium study: Cobblestone appearance with strictures
C. Colonoscopy: Discontinuous transmural ‘skip lesions’ with aphthoid linear ulcers and transverse fissures, non-caseating granulomas, and strictures, Barium study: Cobblestone appearance with strictures
D. Colonoscopy: Normal, Barium study: Lead pipe colon appearance
E. Colonoscopy: Continuous ulcerated lesions involving the mucosa and submucosa, granular mucosa, crypt abscess, and pseudopolyps, Barium study: Lead pipe colon appearance (Correct Answer)

Explanation: ***Colonoscopy: Continuous ulcerated lesions involving the mucosa and submucosa granular mucosa, crypt abscess, and pseudopolyps, Barium study: Lead pipe colon appearance*** - The patient's symptoms (bloody diarrhea, tenesmus, fever, fatigue, weight loss, aphthous stomatitis, red congested conjunctiva, tender swollen joints, anemia, high WBC count) are highly suggestive of **Ulcerative Colitis (UC)**. - **UC** on colonoscopy is characterized by **continuous mucosal and submucosal inflammation**, granular mucosa, crypt abscesses, and **pseudopolyps**. The barium study finding of a **"lead pipe" colon** is classic for long-standing UC due to loss of haustrations. *Colonoscopy: Multiple vascular malformations that resemble telangiectasias on the colon wall, Barium study: Normal* - **Angiodysplasia** presents with vascular malformations, but it typically causes painless lower GI bleeding, not the inflammatory symptoms described. - The patient's severe systemic symptoms (fever, weight loss, anemia, high WBC) are inconsistent with angiodysplasia. *Colonoscopy: Patches of mucosal erosions with pseudomembrane formation, Barium study: Cobblestone appearance with strictures* - **Pseudomembrane formation** is characteristic of **_Clostridioides difficile_ infection**, which has been ruled out by the stool assay. - While "cobblestone appearance" and strictures can be seen in inflammatory bowel disease, the pseudomembranes point away from UC or Crohn's. *Colonoscopy: Discontinuous transmural ‘skip lesions’ with aphthoid linear ulcers and transverse fissures, non-caseating granulomas, and strictures, Barium study: Cobblestone appearance with strictures* - This description is characteristic of **Crohn's disease**, which involves **discontinuous**, **transmural inflammation** with **skip lesions**, aphthoid ulcers, and non-caseating granulomas. - While some symptoms overlap with UC, the involvement of mucocutaneous lesions and generalized systemic symptoms fits better with the continuous inflammation of UC than the patchy disease of Crohn's. *Colonoscopy: Normal, Barium study: Lead pipe colon appearance* - A **normal colonoscopy** would be inconsistent with the patient's severe symptoms of bloody diarrhea, anemia, and elevated inflammatory markers. - A "lead pipe" colon indicates chronic inflammatory changes, which would undoubtedly be visible on colonoscopy.

Question 4: A 31-year-old woman comes to the emergency department because of a 4-day history of fever and diarrhea. She has abdominal cramps and frequent bowel movements of small quantities of stool with blood and mucus. She has had multiple similar episodes over the past 8 months. Her temperature is 38.1°C (100.6°F), pulse is 75/min, and blood pressure is 130/80 mm Hg. Bowel sounds are normal. The abdomen is soft. There is tenderness to palpation in the left lower quadrant with guarding and no rebound. She receives appropriate treatment and recovers. Two weeks later, colonoscopy shows polypoid growths flanked by linear ulcers. A colonic biopsy specimen shows mucosal edema with distorted crypts and inflammatory cells in the lamina propria. Which of the following is the most appropriate recommendation for this patient?

A. Obtain genetic studies now
B. Obtain barium follow-through radiography in 1 year
C. Obtain glutamate dehydrogenase antigen immunoassay now
D. Start annual magnetic resonance cholangiopancreatography screening in 10 years
E. Start annual colonoscopy starting in 8 years (Correct Answer)

Explanation: ***Start annual colonoscopy starting in 8 years*** - The patient's presentation with bloody diarrhea, abdominal cramps, and repetitive episodes is consistent with inflammatory bowel disease (IBD), specifically likely ulcerative colitis given the left lower quadrant tenderness and colonic biopsy findings (distorted crypts, inflammatory cells in lamina propria). - Patients with IBD, particularly ulcerative colitis affecting a significant portion of the colon and diagnosed at a younger age, are at increased risk for colorectal cancer. Annual colonoscopy screening is recommended 8–10 years after diagnosis for early detection and prevention. *Obtain genetic studies now* - While genetic factors play a role in IBD susceptibility, genetic studies are not routinely indicated for diagnosis or management of inflammatory bowel disease, nor do they guide current screening recommendations for colorectal cancer in IBD patients. - Genetic studies would not provide immediate clinical benefit for this patient's acute symptoms or long-term management plan regarding cancer surveillance. *Obtain barium follow-through radiography in 1 year* - Barium follow-through radiography is primarily used to evaluate the small intestine, often in suspected Crohn's disease. This patient's symptoms and colonoscopy findings point towards colonic involvement, making this less appropriate. - Furthermore, this imaging modality uses ionizing radiation and is less sensitive for detecting mucosal changes indicative of dysplasia or early cancer compared to colonoscopy. *Obtain glutamate dehydrogenase antigen immunoassay now* - Glutamate dehydrogenase antigen immunoassay is a test for Clostridioides difficile infection. While C. difficile can cause severe diarrhea and colitis, the patient's history of recurrent episodes over 8 months and the specific colonoscopy findings (polypoid growths, linear ulcers, distorted crypts) are more characteristic of IBD. - Although C. difficile infection can exacerbate IBD, it does not explain the chronic, recurrent nature of her illness or the long-term cancer surveillance needs. *Start annual magnetic resonance cholangiopancreatography screening in 10 years* - MRCP screening is used to monitor for primary sclerosing cholangitis (PSC), a condition associated with IBD, particularly ulcerative colitis. However, PSC screening is performed when clinically indicated (e.g., elevated alkaline phosphatase, cholestatic symptoms), not as routine scheduled surveillance. - This patient has no clinical features suggesting PSC at present, and there is no guideline recommending routine MRCP screening at a predetermined time interval for all IBD patients.

Question 5: A 25-year-old woman presents to the emergency department with fatigue and weakness. She states over the past 24 hours she has not felt like herself and has felt like she has no strength. The patient has no significant past medical history other than a single episode of blood-tinged diarrhea 1 week ago which resolved on its own. Her temperature is 99.4°F (37.4°C), blood pressure is 124/62 mmHg, pulse is 95/min, respirations are 29/min, and oxygen saturation is 95% on room air. Physical exam is notable for 2/5 strength of the lower extremities and decreased sensation in the lower extremities and finger tips. Which of the following is the best initial step in management?

A. IV immunoglobulin
B. Dexamethasone
C. Spirometry (Correct Answer)
D. Intubation
E. Pyridostigmine

Explanation: ***Spirometry*** - The patient's symptoms (fatigue, weakness, decreased strength, and sensation in extremities) following a gastrointestinal infection are highly suggestive of **Guillain-Barré Syndrome (GBS)**. - **Spirometry** is the most critical initial step to assess respiratory function, as **respiratory muscle weakness** is the primary cause of morbidity and mortality in GBS. *IV immunoglobulin* - While **intravenous immunoglobulin (IVIG)** is a treatment for GBS, it is not the *initial* management step. - The immediate priority in suspected GBS is to assess and stabilize the patient's respiratory status, not to initiate definitive treatment. *Dexamethasone* - **Corticosteroids** like dexamethasone have **not been shown to be effective** in treating GBS and may even prolong recovery in some cases. - Their use is generally avoided in the management of GBS. *Intubation* - **Intubation** is indicated if spirometry reveals rapidly declining or severely compromised respiratory function, but it is not the *initial* step. - An assessment of respiratory capacity via spirometry should precede intubation unless acute respiratory failure is immediately apparent. *Pyridostigmine* - **Pyridostigmine** is an anticholinesterase inhibitor used primarily for the symptomatic treatment of **myasthenia gravis**. - It is not indicated for the management of GBS, which involves a different pathophysiological mechanism.

Question 6: A 19-year-old woman comes to the physician because of a 1-year history of severe abdominal pain, bloating, and episodic diarrhea. She also has a 10-kg (22-lb) weight loss over the past 10 months. Physical examination shows a mildly distended abdomen, diffuse abdominal tenderness, and multiple erythematous, tender nodules on the anterior aspect of both legs. There is a small draining lesion in the perianal region. Further evaluation of this patient's gastrointestinal tract is most likely to show which of the following findings?

A. Transmural inflammation (Correct Answer)
B. Melanosis coli
C. Villous atrophy
D. Crypt abscesses
E. No structural abnormalities

Explanation: **Transmural inflammation** - The patient's symptoms (abdominal pain, bloating, diarrhea, weight loss) and extraintestinal manifestations (erythematous nodules, perianal lesion) are classic for **Crohn's disease**. - A hallmark pathological feature of Crohn's disease is **transmural inflammation**, affecting all layers of the bowel wall, which can lead to complications like strictures, fistulas, and abscesses. *Melanosis coli* - This is a harmless condition characterized by **pigmentation of the colonic mucosa** due to chronic laxative use, particularly **anthraquinone laxatives**. - It is not associated with inflammatory bowel disease or the systemic symptoms described. *Villous atrophy* - **Villous atrophy** is the flattening of the villi in the small intestine, most commonly seen in **celiac disease**. - While celiac disease can cause malabsorption and gastrointestinal symptoms, the extraintestinal manifestations and perianal draining lesion are inconsistent with celiac disease. *Crypt abscesses* - **Crypt abscesses** are a characteristic histological finding in **ulcerative colitis**, which primarily affects the colon and rectum. - While ulcerative colitis, like Crohn's, is an inflammatory bowel disease, the presence of transmural inflammation and perianal disease (fistulas/draining lesions) is more indicative of Crohn's. *No structural abnormalities* - The severe symptoms, significant weight loss, and presence of extraintestinal manifestations (erythema nodosum, perianal disease) strongly suggest an underlying structural and inflammatory pathology in the GI tract. - **Irritable Bowel Syndrome (IBS)** typically presents with similar symptoms but lacks structural abnormalities and the systemic inflammatory signs seen here.

Question 7: A 37-year-old man with Crohn disease is admitted to the hospital because of acute small bowel obstruction. Endoscopy shows a stricture in the terminal ileum. The ileum is surgically resected after endoscopic balloon dilatation fails to relieve the obstruction. Three years later, he returns for a follow-up examination. He takes no medications. This patient is most likely to have which of the following physical exam findings?

A. Dry skin and keratomalacia
B. Weakness and ataxia (Correct Answer)
C. Hyperreflexia with tetany
D. Gingival swelling and bleeding
E. Pallor with koilonychia

Explanation: ***Weakness and ataxia*** - This patient with a history of **Crohn disease** and significant **ileal resection** is at high risk for **vitamin B12 deficiency** due to the removal of the primary site of absorption in the terminal ileum. - **Vitamin B12 deficiency** can lead to subacute combined degeneration of the spinal cord, manifesting as **weakness**, **ataxia**, and **paresthesias**. *Dry skin and keratomalacia* - This presentation is indicative of **vitamin A deficiency**, which can occur in malabsorption but is less specific to ileal resection than B12 deficiency. - While fat-soluble vitamins (A, D, E, K) are absorbed in the small intestine, severe isolated vitamin A deficiency causing keratomalacia is not the most likely primary finding after ileal resection. *Hyperreflexia with tetany* - These symptoms typically suggest **hypocalcemia** or **hypomagnesemia**, often due to vitamin D deficiency or malabsorption of minerals. - Although possible with generalized malabsorption, it is not the most characteristic neurological complication following isolated ileal resection compared to vitamin B12 deficiency. *Gingival swelling and bleeding* - This is a hallmark of **scurvy**, caused by **vitamin C deficiency**, which is typically absorbed in the small intestine and does not correlate specifically with ileal resection. - This would be a less likely complication given the specific history compared to micronutrient deficiencies related to terminal ileum function. *Pallor with koilonychia* - **Pallor** and **koilonychia (spoon nails)** are characteristic signs of **iron deficiency anemia**. - While iron is absorbed in the duodenum and proximal jejunum, and anemia is common in Crohn disease, the specific neurological symptoms from B12 deficiency are generally more prominent after ileal resection.

Question 8: A 47-year-old man presents to his primary care physician complaining of pain and stiffness in his right index finger and left knee. The past medical history is remarkable for severe dandruff and an episode of apparent gout in the left 1st toe 6 months ago, which never resolved. The physical examination confirms dactylitis of the right index finger and several toes, as well as synovitis of the left knee. He is also noted to have pitting of his fingernails. Plain X-rays of his hand reveal erosions in the distal interphalangeal (DIP) joint and periarticular new bone formation. Which of the following is most consistent with these findings?

A. Psoriatic arthritis (Correct Answer)
B. Pseudogout
C. Osteoarthritis
D. Reactive arthritis
E. Rheumatoid arthritis

Explanation: ***Psoriatic arthritis*** - The constellation of **dactylitis**, **nail pitting**, involvement of both **DIP joints** with erosions, and a history of **psoriasis** (severe dandruff) is highly characteristic of psoriatic arthritis. - The previous episode resembling gout and synovitis of the knee are also consistent, as psoriatic arthritis can mimic other arthropathies and affect various joints. *Pseudogout* - This condition is caused by **calcium pyrophosphate dihydrate crystal deposition** and typically presents as acute, severe joint pain, often in larger joints like the knee or wrist, but without dermatological or nail changes. - While it can cause synovitis, it does not typically involve dactylitis, DIP erosions, nail pitting, or a history of psoriasis. *Osteoarthritis* - Characterized by **cartilage degeneration** and **new bone formation** (osteophytes), often in weight-bearing joints or DIP/PIP joints, but typically without the marked inflammatory signs like dactylitis or nail changes. - While X-rays can show new bone formation, the presence of dactylitis, nail pitting, and psoriasis history rule out uncomplicated osteoarthritis. *Reactive arthritis* - This is an **acute, inflammatory arthropathy** that typically develops after a genitourinary or gastrointestinal infection. - While it can present with dactylitis and oligoarthritis, it does not involve nail pitting or a history of psoriasis, and the initial trigger infection is usually identifiable. *Rheumatoid arthritis* - This is a **chronic autoimmune disease** primarily affecting smaller joints symmetrically, particularly the MCP and PIP joints, but typically sparing the DIP joints. - It is not associated with psoriasis, nail pitting, and usually presents with periarticular osteopenia rather than significant new bone formation on X-ray.

Question 9: A 61-year-old man comes to the physician because of fatigue, diarrhea, and crampy abdominal pain for 3 weeks. The abdominal pain is worse after eating. During the past week, he has had up to 4 watery stools daily. He has also had pain in his mouth and gums for 6 days. He has not had nausea, vomiting, or fever. Four months ago, he went on a 1-week trip to the Dominican Republic. He has atrial fibrillation, hypertension, and hypothyroidism. Current medications include levothyroxine, metoprolol, and warfarin. He has smoked one pack of cigarettes daily for 40 years. His temperature is 37.9°C (100.2°F), pulse is 81/min, and blood pressure is 120/75 mm Hg. Examination shows two 1-cm, tender ulcerative lesions in the mouth. Abdominal examination shows mild tenderness to palpation in the right lower quadrant without guarding or rebound. Bowel sounds are normal. His hemoglobin concentration is 11.5 g/dL, mean corpuscular volume is 77 fL, leukocyte count is 11,800/mm³, and platelet count is 360,000/mm³. Colonoscopy with biopsy of the colonic mucosa is performed. Analysis of the specimen shows non-caseating granulomas and neutrophilic inflammation of the crypts. Which of the following is the most likely diagnosis?

A. Diverticulitis
B. Whipple disease
C. Crohn disease (Correct Answer)
D. Celiac disease
E. Tropical sprue

Explanation: ***Crohn disease*** - The presence of **fatigue, diarrhea, crampy abdominal pain worse after eating, oral ulcers, and mild right lower quadrant tenderness** is highly suggestive of Crohn disease. - The colonoscopy finding of **non-caseating granulomas** with **neutrophilic inflammation of the crypts** is a classic histopathological hallmark of Crohn disease. *Diverticulitis* - Typically presents with **left lower quadrant pain**, fever, and leukocytosis, usually without oral lesions or chronic diarrhea. - Histopathology would show **inflammation of diverticula**, not non-caseating granulomas. *Whipple disease* - Characterized by **malabsorption, arthralgias, neurological symptoms, and lymphadenopathy,** caused by *Tropheryma whipplei*. - Biopsy would reveal **PAS-positive macrophages** with bacilliform bodies, not non-caseating granulomas or neutrophilic crypt inflammation. *Celiac disease* - Triggered by **gluten ingestion**, leading to malabsorption, diarrhea, and abdominal pain, but often associated with **iron deficiency anemia** and weight loss. - Diagnosis is made by biopsy showing **villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes**, not granulomas. *Tropical sprue* - A chronic diarrheal illness defined by **malabsorption** in individuals residing in or visiting tropical regions, often leading to **folate or B12 deficiency**. - Biopsy findings include **partial villous atrophy and inflammatory cell infiltration** of the lamina propria, distinct from granulomas.

Question 10: A 25-year-old man presents to the emergency department for severe abdominal pain. The patient states that for the past week he has felt fatigued and had a fever. He states that he has had crampy lower abdominal pain and has experienced several bouts of diarrhea. The patient states that his pain is somewhat relieved by defecation. The patient returned from a camping trip 2 weeks ago in the Rocky Mountains. He is concerned that consuming undercooked meats on his trip may have caused this. He admits to consuming beef and chicken cooked over a fire pit. The patient is started on IV fluids and morphine. His temperature is 99.5°F (37.5°C), blood pressure is 130/77 mmHg, pulse is 90/min, respirations are 12/min, and oxygen saturation is 98% on room air. Laboratory studies are ordered and are seen below. Hemoglobin: 10 g/dL Hematocrit: 28% Leukocyte count: 11,500 cells/mm^3 with normal differential Platelet count: 445,000/mm^3 Serum: Na+: 140 mEq/L Cl-: 102 mEq/L K+: 4.1 mEq/L HCO3-: 24 mEq/L BUN: 24 mg/dL Glucose: 145 mg/dL Creatinine: 1.4 mg/dL Ca2+: 9.6 mg/dL Erythrocyte sedimentation rate (ESR): 75 mm/hour Physical exam is notable for a patient who appears to be uncomfortable. Gastrointestinal (GI) exam is notable for abdominal pain upon palpation. Ear, nose, and throat exam is notable for multiple painful shallow ulcers in the patient's mouth. Inspection of the patient's lower extremities reveals a pruritic ring-like lesion. Cardiac and pulmonary exams are within normal limits. Which of the following best describes this patient's underlying condition?

A. p-ANCA positive autoimmune bowel disease
B. Transmural granulomas in the bowel (Correct Answer)
C. Gram-negative microaerophilic organism
D. Rectal mucosa outpouching
E. Bowel wall spasticity

Explanation: ***Transmural granulomas in the bowel*** - This patient's symptoms, including **chronic diarrhea**, **abdominal pain relieved by defecation**, **oral ulcers**, **fatigue**, **fever**, and **elevated ESR**, along with a **pruritic ring-like lesion** (suggestive of erythema nodosum, a common extraintestinal manifestation), are highly indicative of **Crohn's disease**. - **Crohn's disease** is characterized by **transmural inflammation** of any part of the GI tract, often with the formation of **non-caseating granulomas**. *p-ANCA positive autoimmune bowel disease* - This describes **ulcerative colitis**, which is typically associated with **p-ANCA positivity** in a subset of patients. - Unlike the diffuse and continuous inflammation seen in ulcerative colitis, Crohn's disease features **skip lesions** and **transmural inflammation**, which aligns better with the varied symptoms and extraintestinal manifestations presented. *Gram-negative microaerophilic organism* - This refers to bacterial infections such as those caused by **Campylobacter jejuni** or **Helicobacter pylori**, which can cause GI symptoms. - While the patient's camping trip and consumption of undercooked meat might suggest an infectious etiology, the **chronic nature of symptoms** (week-long fatigue and fever), **oral ulcers**, **elevated ESR**, and **erythema nodosum-like lesion** point more strongly towards an autoimmune/inflammatory bowel disease rather than an acute bacterial infection. *Rectal mucosa outpouching* - **Diverticula** are outpouchings of the colon, commonly affecting the sigmoid colon, and are typically associated with **diverticulitis** when inflamed. - This condition does not explain the widespread systemic symptoms, oral ulcers, or the chronic, crampy abdominal pain and diarrhea pattern seen in this patient. *Bowel wall spasticity* - **Bowel spasticity** is a feature of **irritable bowel syndrome (IBS)**. - While IBS can cause crampy abdominal pain and changes in bowel habits, it is a **functional disorder** and does not cause **fever**, **oral ulcers**, **elevated ESR**, or significant **anemia** and **thrombocytosis** as seen in this patient.

Question 11: A 24-year-old woman presents to the clinic with chronic abdominal discomfort and cramping. She seeks medical attention now as she is concerned about the diarrhea that she has developed that is occasionally mixed with tiny streaks of blood. Her medical history is significant for lactose intolerance and asthma. She has a family history of wheat allergy and reports that she has tried to make herself vomit on several occasions to lose weight. After counseling the patient about the dangers of bulimia, physical examination reveals the rectum is red, inflamed, tender, and a perirectal abscess is seen draining purulent material. Colonoscopy demonstrates scattered mucosal lesions involving the colon and terminal ileum. A complete blood count is given below: Hb%: 10 gm/dL Total count (WBC): 12,500/mm3 Differential count: Neutrophils: 50% Lymphocytes: 40% Monocytes: 5% ESR: 22 mm/hr What is the most likely diagnosis?

A. Ulcerative colitis
B. Celiac disease
C. Irritable bowel syndrome
D. Crohn’s disease (Correct Answer)
E. Laxative abuse

Explanation: ***Crohn’s disease*** - The presence of **abdominal discomfort, cramping, bloody diarrhea, perirectal abscess**, and **scattered mucosal lesions involving the colon and terminal ileum** are classic findings consistent with Crohn's disease. The involvement of the terminal ileum is a hallmark of Crohn's. - Anemia (Hb% 10 gm/dL), leukocytosis (WBC 12,500/mm3), and elevated ESR (22 mm/hr) indicate **chronic inflammation** and are common in Crohn's disease. *Ulcerative colitis* - While ulcerative colitis presents with bloody diarrhea and abdominal discomfort, it typically involves **continuous inflammation confined to the colon** and rectum, without skip lesions or involvement of the terminal ileum. - Perirectal abscesses are also less common in ulcerative colitis compared to Crohn's disease. *Celiac disease* - Celiac disease is an autoimmune disorder triggered by **gluten**, primarily affecting the **small intestine** and presenting with malabsorption, diarrhea, and abdominal pain. However, it does not typically cause bloody diarrhea, perirectal abscesses, or colon inflammation visible on colonoscopy. - While there is a family history of wheat allergy, the clinical picture is more indicative of inflammatory bowel disease. *Irritable bowel syndrome* - IBS is characterized by chronic abdominal pain, discomfort, and altered bowel habits (diarrhea, constipation, or both), but it is a **functional gastrointestinal disorder** without evidence of inflammation, structural abnormalities, or bloody stools. - The presence of bloody diarrhea, perirectal abscess, and inflammatory markers rules out IBS. *Laxative abuse* - Laxative abuse can cause chronic diarrhea, abdominal cramping, and electrolyte disturbances, but it does **not cause inflammatory changes** such as mucosal lesions, bloody diarrhea, or perirectal abscesses seen on colonoscopy. - While a history of bulimia is mentioned, the specific findings point towards an inflammatory process.

Question 12: A 28-year-old woman comes to the physician because of a 2-month history of multiple right inframammary lumps. They are tender and have a foul-smelling odor. She has had previous episodes of painful swellings in the axillae 12 months ago that resolved with antibiotic therapy, leaving some scarring. She has Crohn disease. Menses occur at irregular 18- to 40-day intervals and last 1–5 days. The patient's only medication is mesalamine. She appears anxious. She is 162 cm (5 ft 4 in) tall and weighs 87 kg (192 lb); BMI is 33 kg/m2. Vital signs are within normal limits. Examination of the right inframammary fold shows multiple tender, erythematous nodules and fistulas with purulent discharge. Hirsutism is present. Her fasting glucose concentration is 136 mg/dL. Which of the following areas is most likely to also be affected by this patient's condition?

A. Forehead
B. Back
C. Shin
D. Central face
E. Groin (Correct Answer)

Explanation: ***Groin*** - The patient's presentation with recurrent tender, foul-smelling lumps in the **inframammary fold** and past episodes in the **axillae**, along with scarring, strongly suggests **hidradenitis suppurativa (HS)**. HS commonly affects areas with a high density of apocrine glands, including the **axillae, groin, inframammary folds**, and anogenital region. - Her history of **Crohn disease**, obesity (BMI 33 kg/m²), and possible insulin resistance (fasting glucose 136 mg/dL) are all associated risk factors for HS. The groin is another typical site for lesions. *Forehead* - The forehead is generally considered part of the **T-zone of the face**, where sebaceous glands are abundant, but it is not a primary site for *hidradenitis suppurativa*. - Lesions in this area are more commonly associated with **acne vulgaris** or other folliculitis, which typically present differently. *Back* - While the back can be affected by various follicular conditions like **acne inversa** or folliculitis, it is not a primary or highly characteristic site for the deep, painful, and recurring lesions of *hidradenitis suppurativa* in the way intertriginous areas are. - The specific pattern of involvement in **skin folds** points away from the broader back area as an equally likely site. *Shin* - The shins are not typically affected by *hidradenitis suppurativa* as they lack the high concentration of **apocrine glands** found in the classic affected areas. - Lesions on the shin are more characteristic of conditions like **erythema nodosum** or other forms of vasculitis, which have different presentations. *Central face* - The central face, like the forehead, is rich in **sebaceous glands** and is a common site for conditions like **acne vulgaris** or rosacea. - However, it is not a typical anatomical location for the characteristic deep, recurrent abscesses and sinus tracts seen in *hidradenitis suppurativa*.

Question 13: A 42-year-old woman comes to the physician because of increasing fatigue and difficulty concentrating at work for the last 2 months. She has hypertension and a 22-year history of Crohn disease. She has been hospitalized and treated for acute exacerbations, sometimes involving strictures, multiple times in the past. She has not had significant gastrointestinal symptoms in over a year. Current medications include mesalamine, thiazide, and bisoprolol. Her temperature is 37.2°C (99°F), pulse is 72/min, and blood pressure is 140/90 mm Hg. Examination shows a soft abdomen and pale conjunctivae. Rectal examination is unremarkable. Laboratory studies show: Hemoglobin 9.4 g/dL Mean corpuscular volume 112 fL Mean corpuscular hemoglobin 37.2 pg/cell Leukocyte count 8,700 /mm3 Platelet count 150,000 /mm3 Erythrocyte sedimentation rate 42 mm/h Serum Ferritin 88 ng/mL Iron 117 μg/dL Thyroid-stimulating hormone 3.2 μU/mL Thyroxine 7 μg/dL Further evaluation of this patient is most likely to reveal which of the following findings?

A. Unexplained weight gain
B. Impaired vision in her right eye
C. Decreased vibratory sensation (Correct Answer)
D. Tarry stools
E. Dark-colored urine

Explanation: ***Decreased vibratory sensation*** - The patient's **macrocytic anemia** (elevated MCV of 112 fL) combined with a history of **Crohn's disease**, which often affects the **terminal ileum**, strongly suggests **vitamin B12 deficiency** due to malabsorption. - **Vitamin B12 deficiency** can lead to **subacute combined degeneration** of the spinal cord, causing neurological symptoms like decreased vibratory sensation, proprioception, and ataxia. *Unexplained weight gain* - The patient has symptoms like fatigue and difficulty concentrating, which could be associated with systemic illness, but the lab findings point specifically to **anemia** and potential **malabsorption**, not weight gain. - While some endocrine disorders can cause fatigue and weight gain, the specific hematological findings here are more indicative of a **nutritional deficiency**. *Impaired vision in her right eye* - Ocular symptoms are not typically associated with the **macrocytic anemia** or **Crohn's related malabsorption** described in this patient, although some inflammatory conditions associated with Crohn's can affect the eyes. - The primary neurological findings in **vitamin B12 deficiency** are sensory and motor deficits, not acute vision loss. *Tarry stools* - **Tarry stools (melena)** indicate **upper gastrointestinal bleeding**, which typically causes **iron-deficiency anemia** (microcytic) rather than the macrocytic anemia observed. - The patient has been free of significant gastrointestinal symptoms for over a year and her current lab values are inconsistent with active GI bleeding. *Dark-colored urine* - **Dark-colored urine** can be due to various causes such as **rhabdomyolysis**, **hemolysis**, or certain medications, but it is not a characteristic sign of **macrocytic anemia** or **vitamin B12 deficiency**. - There are no other features in the patient's presentation or lab work (e.g., elevated bilirubin, signs of hemolytic anemia) to suggest a cause for dark urine.

Question 14: A 33-year-old primigravid visits the clinic at the 22 weeks’ gestation with concerns about several episodes of loose watery stool over the past 4 months, which are sometimes mixed with blood. Use of over-the-counter antidiarrheal medications has not been helpful. She also reports having painful ulcers in her mouth for the last 2 months. Pregnancy has been otherwise uncomplicated so far. On physical examination, the blood pressure is 110/60 mm Hg, the pulse rate is 90/min, the respiratory rate is 19/min, and the temperature is 36.6°C (97.8°F). There is bilateral conjunctival redness. Abdominal examination shows minimal tenderness but no guarding or rebound tenderness. Fundal height is proportionate to 22 weeks of gestation, and fetal heart sounds are audible. Colonoscopy shows focal areas of inflammation in the ileum, separated by normal mucosa, with rectal sparing. Based on the colonoscopy results, which of the following complications is the patient at risk for?

A. Carcinoid syndrome
B. Metastasis to the liver
C. Intestinal obstruction (Correct Answer)
D. Paralytic ileus
E. Primary sclerosing cholangitis

Explanation: ***Intestinal obstruction*** - Crohn's disease, characterized by **transmural inflammation** in the **ileum** with skipped lesions, often leads to **stricture formation** and **fibrosis**, increasing the risk of bowel obstruction. - The patient's symptoms of chronic diarrhea and blood in the stool, coupled with oral ulcers and conjunctivitis, indicate **Crohn's disease**, which commonly affects the terminal ileum and can lead to complications such as strictures and subsequently, intestinal obstruction. *Carcinoid syndrome* - Carcinoid syndrome is caused by neuroendocrine tumors that secrete **vasoactive substances**, leading to symptoms like **flushing**, **diarrhea**, and **right-sided heart valve disease**. - There is no evidence of neuroendocrine tumor activity or related systemic symptoms beyond the gastrointestinal manifestations common in inflammatory bowel disease. *Metastasis to the liver* - Metastasis to the liver implies a primary malignancy, and while patients with inflammatory bowel disease have an increased risk of certain cancers, there is **no direct evidence or typical presentation** in this case to suggest liver metastases. - The patient's symptoms are more indicative of an **inflammatory process** like Crohn's disease rather than a malignant one with liver involvement. *Paralytic ileus* - Paralytic ileus involves a **temporary arrest of bowel motility** without mechanical obstruction, often due to abdominal surgery, peritonitis, or metabolic derangements. - The chronic nature of the patient's symptoms and the specific colonoscopy findings pointing to **focal inflammation and strictures** are more consistent with a mechanical obstruction caused by Crohn's disease, not paralytic ileus. *Primary sclerosing cholangitis* - Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease often associated with **ulcerative colitis**, characterized by inflammation and fibrosis of the bile ducts. - While PSC can be associated with inflammatory bowel disease, it is more commonly linked to **ulcerative colitis** rather than Crohn's disease, and there are no signs of cholestasis or liver involvement in this patient's presentation.

Question 15: A 26-year-old male presents to the emergency room with weight loss, abdominal pain, and bloody diarrhea. He reports having intermittent bloody stools and crampy left lower quadrant abdominal pain over the past several days. He is otherwise healthy, does not smoke, and takes no medications. His family history is notable for colon cancer in his father. He subsequently undergoes a colonoscopy which demonstrates a hyperemic friable mucosa with inflammation extending continuously from the rectum proximally through the colon. A biopsy of the rectal mucosa is notable for crypt abscesses and pseudopolyps. This patient’s condition is most commonly associated with what other condition?

A. Primary sclerosing cholangitis (Correct Answer)
B. Primary biliary cholangitis
C. Intestinal strictures
D. Perianal fistulae
E. Aphthous ulcers

Explanation: **Primary sclerosing cholangitis** - The described clinical picture (weight loss, abdominal pain, bloody diarrhea, continuous inflammation from the rectum proximally, crypt abscesses, pseudopolyps) is highly characteristic of **ulcerative colitis (UC)**. - **Primary sclerosing cholangitis (PSC)** is a chronic cholestatic liver disease strongly associated with UC, occurring in 5-10% of UC patients. *Primary biliary cholangitis* - **Primary biliary cholangitis (PBC)**, formerly known as primary biliary cirrhosis, is an autoimmune liver disease primarily affecting small intrahepatic bile ducts, but it is typically associated with other autoimmune conditions like Sjögren's syndrome or rheumatoid arthritis, not inflammatory bowel disease (IBD). - PBC is characterized by the presence of **antimitochondrial antibodies (AMA)** and predominantly affects middle-aged women. *Intestinal strictures* - While intestinal strictures can occur in inflammatory bowel disease, they are much more characteristic of **Crohn's disease**, which involves transmural inflammation and can lead to fibrosis and narrowing of the bowel lumen. - Ulcerative colitis, with its mucosal inflammation, is less likely to cause strictures, though sometimes severe inflammation can lead to a toxic megacolon. *Perianal fistulae* - **Perianal fistulae** are a common complication of **Crohn's disease**, resulting from transmural inflammation and abscess formation penetrating the skin around the anus. - They are extremely rare in ulcerative colitis, which primarily affects the colonic mucosa. *Aphthous ulcers* - **Aphthous ulcers** in the mouth can be an extraintestinal manifestation of inflammatory bowel disease, particularly **Crohn's disease**. - While they can occur in UC, they are less specific and less commonly the most significant associated condition compared to PSC.

Question 16: A 33-year-old man presents to the clinic complaining of multiple painful joints for the past 2 weeks. The patient notes no history of trauma or any joint disorders. The patient states that he is generally healthy except for a recent emergency room visit for severe bloody diarrhea, which has resolved. On further questioning, the patient admits to some discomfort with urination but notes no recent sexual activity. On examination, the patient is not in acute distress, with no joint deformity, evidence of trauma, swelling, or erythema. He has a decreased range of motion of his right knee secondary to pain. Vital signs are as follows: heart rate 75/min, blood pressure 120/78 mm Hg, respiratory rate 16/min, and temperature 37.3°C (99.0°F). What is the next step in the treatment of this patient?

A. Intravenous (IV) antibiotics
B. Prostate biopsy
C. Serology for rheumatoid factor
D. Positron emission tomography (PET) scan
E. Nonsteroidal anti-inflammatory drugs (NSAIDs) (Correct Answer)

Explanation: ***Nonsteroidal anti-inflammatory drugs (NSAIDs)*** - This patient's presentation of **arthritis** following an episode of **bloody diarrhea** and discomfort with urination is highly suggestive of **reactive arthritis**. - **NSAIDs** are the **first-line treatment** for managing the pain and inflammation associated with reactive arthritis. *Intravenous (IV) antibiotics* - While reactive arthritis can be triggered by a preceding infection, antibiotics are generally **not effective** for established reactive arthritis as the condition is thought to be an **immune-mediated response** to bacterial antigens, not ongoing infection in the joints. - Antibiotics may be indicated if there is an **active, ongoing infection** in another system that is the source of the antigens, but the diarrhea has already resolved. *Prostate biopsy* - The patient's discomfort with urination could suggest **prostatitis** or **urethritis**, which can be part of the reactive arthritis syndrome or a trigger. - However, a **prostate biopsy** is an invasive procedure primarily used for diagnosing prostate cancer and is **not indicated** for the symptomatic management or initial diagnosis of reactive arthritis or simple urethral discomfort. *Serology for rheumatoid factor* - While reactive arthritis can cause joint pain, it is a **seronegative spondyloarthropathy**, meaning **rheumatoid factor (RF)** is typically **negative**. - Testing for RF would be more relevant if **rheumatoid arthritis** were suspected, but the clinical picture (recent infection, type of joint involvement) points away from RA. *Positron emission tomography (PET) scan* - A **PET scan** is an advanced imaging technique used to detect metabolically active cells, often in the context of cancer, infection, or inflammation in specific situations. - It is **not a standard diagnostic or therapeutic tool** for reactive arthritis and would be an **overly aggressive and inappropriate initial step** for this patient's presentation.

Question 17: A 22-year-old woman comes to the physician because of a 1-month history of persistent abdominal cramping, diarrhea, and rectal pain. During the past 2 weeks, she has had up to 4 small volumed, blood-tinged stools with mucus daily. She has also had intermittent fevers and a 4.5-kg (10-lb) weight loss during this time. She traveled to Southeast Asia 3 months ago and received all appropriate vaccinations and medications beforehand. She has no history of serious illness and takes no medications. Her temperature is 37.2°C (99°F), pulse is 90/min, respirations are 16/min, and blood pressure is 125/80 mm Hg. The abdomen is soft, and there is tenderness to palpation of the left lower quadrant with guarding but no rebound. Bowel sounds are normal. The stool is brown, and a test for occult blood is positive. Flexible sigmoidoscopy shows a granular, hyperemic, and friable rectal mucosa that bleeds easily on contact. Which of the following is this patient at greatest risk of developing?

A. Oral ulcers
B. Colorectal cancer (Correct Answer)
C. Hemolytic uremic syndrome
D. Colonic granulomas
E. Gastric cancer

Explanation: ***Colorectal cancer*** - The patient's symptoms (abdominal cramping, diarrhea, rectal pain, bloody stools, weight loss, fever) and sigmoidoscopy findings (granular, hyperemic, friable rectal mucosa) are classic for **inflammatory bowel disease (IBD)**, specifically **ulcerative colitis**. - Patients with ulcerative colitis are at significantly **increased risk of developing colorectal cancer** due to chronic inflammation, with risk increasing with disease duration and extent of colonic involvement. - **Surveillance colonoscopy** is recommended starting 8-10 years after diagnosis for patients with extensive colitis, making colorectal cancer the most important long-term complication to monitor. *Oral ulcers* - While **aphthous oral ulcers** can be an extraintestinal manifestation of inflammatory bowel disease (Crohn's disease more commonly than ulcerative colitis), they are not a serious complication and do not represent the greatest long-term risk. - They are also not mentioned in her current presentation. *Hemolytic uremic syndrome* - **Hemolytic uremic syndrome (HUS)** is characterized by **microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury**, often triggered by certain bacterial infections (e.g., E. coli O157:H7). - There is no evidence of hemolytic anemia, thrombocytopenia, or kidney injury in this patient, and her symptoms are more consistent with chronic inflammatory bowel disease rather than an acute infectious colitis leading to HUS. *Colonic granulomas* - **Granulomas** are characteristic histological findings in **Crohn's disease**, another type of inflammatory bowel disease. - However, they are **typically absent in ulcerative colitis**, which is suggested by the presentation focusing on rectal and left-sided colonic inflammation. - Granulomas are a pathologic finding, not a complication or risk that the patient would develop. *Gastric cancer* - While some conditions like **Helicobacter pylori infection** or **pernicious anemia** increase the risk of gastric cancer, there is no direct link between inflammatory bowel disease (especially ulcerative colitis) and an increased risk of gastric cancer. - The patient's symptoms are localized to the lower gastrointestinal tract.

Question 18: A 26-year-old man comes to the emergency room complaining of severe, episodic back pain. He states that it started suddenly this morning. The pain is 9/10 and radiates to his left groin. He endorses seeing blood in his urine earlier but denies dysuria or abnormal urethral discharge. His medical history is significant for Crohn disease, gout, and insulin-dependent diabetes. He takes insulin, allopurinol, and sulfasalazine. He is sexually active with multiple women and uses condoms inconsistently. He drinks 4 cans of beer on the weekends. He denies tobacco use or other recreational drug use. The patient’s temperature is 99°F (37.2°C), blood pressure is 121/73 mmHg, pulse is 89/min, and respirations are 14/min with an oxygen saturation of 94% on room air. A contrast computed tomography of the abdomen and pelvis reveals a 5-mm stone in the left ureter without evidence of hydronephrosis. Urinalysis and urine microscopy reveal hematuria and envelope-shaped crystals. Which of the following most likely contributed to the development of the patient’s acute symptoms?

A. Gout
B. Medication effect
C. Sexual history
D. Crohn disease (Correct Answer)
E. Diabetes mellitus

Explanation: ***Crohn disease*** - Patients with Crohn disease are at increased risk of **calcium oxalate kidney stones** due to altered enterohepatic circulation of bile acids, leading to increased oxalate absorption. - The combination of severe flank pain radiating to the groin, visible hematuria, and **envelope-shaped crystals** (calcium oxalate) in the urine strongly points to a kidney stone related to his Crohn disease. *Gout* - Gout typically causes **monoarticular arthritis** and is associated with **uric acid crystals**, not calcium oxalate. - While allopurinol is used to prevent gout flares, it does not directly cause calcium oxalate stones. *Medication effect* - The patient's medications (insulin, allopurinol, sulfasalazine) are generally not associated with the formation of **calcium oxalate stones**. - Allopurinol primarily manages uric acid levels, and sulfasalazine is for Crohn disease, neither of which directly promotes calcium oxalate stone formation. *Sexual history* - An inconsistent condom use and multiple partners elevate the risk of **sexually transmitted infections**, which are not typically linked to kidney stone formation. - Symptoms like urethritis or prostatitis would be expected with STIs, not severe back pain and hematuria from a ureteral stone. *Diabetes mellitus* - Diabetes is a risk factor for various renal complications, such as **diabetic nephropathy**, but not specifically for acute calcium oxalate kidney stones as the primary cause of these acute symptoms. - Kidney stones are not a typical acute complication of uncontrolled diabetes in this manner.

Question 19: A 37-year-old man presents to his gastroenterologist due to a transaminitis found by his primary care physician (PCP). He reports currently feeling well and has no acute concerns. Medical history is significant for ulcerative colitis treated with 5-aminosalicylate. He recently went on a trip to Mexico and experienced an episode of mild diarrhea. The patient is 5 ft 4 in and weighs 220 lbs (99.8 kg). His temperature is 98°F (36.7°C), blood pressure is 138/88 mmHg, pulse is 90/min, and respirations are 18/min. Physical examination is unremarkable. Laboratory testing demonstrates: Leukocyte count: 7,200 /mm^3 Alkaline phosphatase: 205 U/L Aspartate aminotransferase (AST): 120 U/L Alanine aminotransferase (ALT): 115 U/L Perinuclear antineutrophil cytoplasmic antibody (pANCA): Positive Antimitochondrial antibody: Negative Which of the following is most likely the diagnosis?

A. Choledocholithiasis
B. Acute cholecystitis
C. Acute viral hepatitis
D. Primary sclerosing cholangitis (Correct Answer)
E. Primary biliary cholangitis

Explanation: ***Primary sclerosing cholangitis*** - The patient's history of **ulcerative colitis**, elevated **alkaline phosphatase**, and positive **pANCA** are highly suggestive of primary sclerosing cholangitis (PSC). - PSC often presents with **asymptomatic transaminitis** in early stages and is strongly associated with inflammatory bowel disease, particularly ulcerative colitis. *Choledocholithiasis* - This condition is characterized by **gallstones in the common bile duct**, usually presenting with **biliary colic**, jaundice, or cholangitis. - While it can cause elevated liver enzymes, particularly alkaline phosphatase, the chronic, asymptomatic nature and strong association with ulcerative colitis and pANCA positivity point away from choledocholithiasis as the *most likely* diagnosis. *Acute cholecystitis* - **Acute cholecystitis** involves inflammation of the gallbladder, typically causing **right upper quadrant pain**, fever, and leukocytosis. - The patient is asymptomatic, afebrile, and has an unremarkable physical exam, making acute cholecystitis unlikely. *Acute viral hepatitis* - **Acute viral hepatitis** usually presents with significantly higher **aminotransferase levels** (often in the thousands) and symptoms like fatigue, nausea, and jaundice. - The patient's relatively mild transaminitis, asymptomatic status, and specific risk factors (ulcerative colitis, pANCA) do not fit the typical picture of acute viral hepatitis. *Primary biliary cholangitis* - **Primary biliary cholangitis (PBC)** is characterized by destruction of small intrahepatic bile ducts, primarily affecting women, and is associated with **anti-mitochondrial antibodies (AMA)**. - The patient is male, and his AMA is negative, making PBC an unlikely diagnosis, despite the elevated alkaline phosphatase.

Question 20: A 44-year-old woman comes to the physician with increasingly yellow sclera and pruritus over the past 3 months. She has intermittent right-upper-quadrant pain and discomfort. She has no history of any serious illnesses and takes no medications. Her vital signs are within normal limits. Her sclera are icteric. Skin examination shows linear scratch marks on the trunk and limbs. The remainder of the physical examination is unremarkable. Laboratory studies show: Complete blood count Hemoglobin 15 g/dL Mean corpuscular volume 95 μm3 Leukocyte count 6,000/mm3 with a normal differential Serum Alkaline phosphatase 470 U/L Aspartate aminotransferase (AST, GOT) 38 U/L Alanine aminotransferase (ALT, GPT) 45 U/L γ-Glutamyltransferase (GGT) 83 U/L (N=5–50 U/L) Bilirubin, total 2.7 mg/dL Bilirubin, direct 1.4 mg/dL Magnetic resonance cholangiopancreatography (MRCP) shows a multifocal and diffuse beaded appearance of the intrahepatic and extrahepatic biliary ducts. Which of the following is the most appropriate diagnostic study at this time?

A. No further testing is indicated
B. Colonoscopy (Correct Answer)
C. Liver biopsy
D. Upper endoscopy
E. Endoscopic retrograde cholangiopancreatography (ERCP)

Explanation: ***Colonoscopy*** - The patient's presentation with **pruritus**, **jaundice**, elevated **alkaline phosphatase**, and characteristic **beaded appearance of biliary ducts** on MRCP is highly suggestive of **Primary Sclerosing Cholangitis (PSC)**. - Approximately **60-80% of patients with PSC** have concomitant **inflammatory bowel disease (IBD)**, particularly **ulcerative colitis**. - **Colonoscopy with biopsies** is the most appropriate next step to screen for IBD, as it allows visualization of the entire colon and can detect pancolitis or right-sided disease that would be missed by sigmoidoscopy. - Early detection of IBD is important for management and colorectal cancer surveillance, as PSC-IBD patients have increased risk of colorectal malignancy. *No further testing is indicated* - This is incorrect because the patient has clear signs of PSC, and further evaluation is necessary to screen for **associated IBD**, which occurs in the majority of PSC patients. - Identifying concurrent IBD affects prognosis, management, and surveillance strategies for colorectal cancer. *Liver biopsy* - While liver biopsy can provide histological confirmation and staging information, the **MRCP findings of multifocal beaded strictures** are highly specific for PSC and are generally considered **diagnostic**. - Biopsy carries risks and is typically reserved for cases where imaging is equivocal or when assessing fibrosis stage is critical for management decisions. - Given the classic MRCP findings, screening for IBD takes priority over liver biopsy. *Upper endoscopy* - **Upper endoscopy** evaluates the esophagus, stomach, and duodenum. - It is not appropriate for screening inflammatory bowel disease or evaluating the biliary tree in the context of suspected PSC. - Upper endoscopy would be indicated if the patient had upper GI symptoms or if screening for varices was needed in cirrhotic patients. *Endoscopic retrograde cholangiopancreatography (ERCP)* - While **ERCP** can visualize the biliary tree, it is an **invasive procedure** with significant risks including **pancreatitis** (3-5% risk), cholangitis, and perforation. - Given that **MRCP has already demonstrated the characteristic findings** of PSC non-invasively, ERCP is reserved for **therapeutic interventions** (e.g., balloon dilation of dominant strictures, stent placement, or bile duct brushings if cholangiocarcinoma is suspected). - ERCP is not appropriate as a diagnostic study when MRCP has already established the diagnosis.

Question 21: A 22-year-old white woman comes to the physician because of a 6-month history of lower abdominal pain. She has also had multiple episodes of loose stools with blood during this period. She has had painful bowel movements for 1 month. Over the past year, she has had a 10-kg (22-lb) weight loss. She was treated for streptococcal pharyngitis last week. Her maternal grandfather died of colon cancer at the age of 52 years. She does not smoke. She drinks three to five beers on social occasions. She is 162 cm (5 ft 4 in) tall and weighs 52 kg (115-lb); BMI is 19.7 kg/m2. Her temperature is 37°C (98.6°F), pulse is 60/min, respirations are 13/min, and blood pressure is 110/70 mm Hg. Cardiopulmonary examination shows no abnormalities. The abdomen is soft and there is tenderness to palpation of the left lower quadrant. There is no guarding or rigidity. Rectal examination shows no masses. Laboratory studies show: Hemoglobin 10.4 g/dL Leukocyte count 10,800/mm3 Platelet count 450,000/mm3 Serum Na+ 138 mEq/L Cl- 103 mEq/L K+ 4.9 mEq/L HCO3- 22 mEq/L Urea nitrogen 18 mg/dL Creatinine 0.6 mg/dL Antinuclear antibodies negative Perinuclear antineutrophil cytoplasmic antibodies positive Anti-Saccharomyces cerevisiae antibodies negative A colonoscopy is scheduled for the next day. Which of the following findings is most likely to be present on colonoscopy of this patient?

A. Confluent inflammation of the colonic mucosa with edema, fibrin-covered ulcers, and loss of vascular pattern (Correct Answer)
B. Numerous polyps extending throughout the colon
C. Patchy inflammation of mucosa with cobblestone appearance and intervening areas of normal mucosa
D. Pseudomembranes overlying regions of colonic inflammation
E. Normal colonic mucosa

Explanation: ***Confluent inflammation of the colonic mucosa with edema, fibrin-covered ulcers, and loss of vascular pattern*** - This description is characteristic of **ulcerative colitis (UC)**, which is strongly indicated by the patient's symptoms (lower abdominal pain, bloody loose stools, painful bowel movements, weight loss) and **positive p-ANCA**. - UC typically presents with continuous inflammation starting from the rectum and extending proximally, featuring **erythema, edema, friability, ulcerations**, and a **loss of the normal vascular pattern**. *Numerous polyps extending throughout the colon* - This finding is more indicative of conditions like **familial adenomatous polyposis (FAP)** or sometimes chronic inflammatory conditions with dysplasia, but not the primary presentation of acute inflammatory bowel disease. - While chronic UC can lead to **dysplasia and polyps**, the acute symptoms and specific p-ANCA positivity point directly to active inflammation rather than diffuse polyposis as the most likely initial finding. *Patchy inflammation of mucosa with cobblestone appearance and intervening areas of normal mucosa* - This description is classic for **Crohn's disease**, which is characterized by **skip lesions**, transmural inflammation, and a **cobblestone appearance** due to deep ulcerations and edematous mucosa. - The patient's **positive p-ANCA** and **left lower quadrant tenderness** are more consistent with UC, while **Crohn's disease** is typically associated with **ASCA positivity** and often affects the terminal ileum. *Pseudomembranes overlying regions of colonic inflammation* - **Pseudomembranes** are pathognomonic for **Clostridioides difficile infection (CDI)**, which is typically characterized by watery diarrhea, abdominal pain, and often follows antibiotic use. - Although the patient's recent **streptococcal pharyngitis** treatment could potentially be a risk factor for CDI, the chronic nature of her symptoms (6 months), significant weight loss, and specific p-ANCA positivity make **inflammatory bowel disease** far more likely. *Normal colonic mucosa* - Given the patient's persistent and severe symptoms, including bloody stools, significant weight loss, and an inflammatory marker (elevated leukocyte and platelet counts), it is highly unlikely that her colonic mucosa would appear normal. - These clinical features strongly point towards an underlying **inflammatory process** requiring endoscopic evaluation.

Question 22: A 28-year-old woman presents with right lower quadrant abdominal pain, fatigue, and low-volume diarrhea of intermittent frequency for the past 4 months. She also reports weight loss and believes it to be due to a decreased appetite. She has noticed herself being more "forgetful" and she denies seeing any blood in her stool, changes in diet, infection, or recent travel history. Her temperature is 99.5°F (37.5°C), blood pressure is 112/72 mmHg, pulse is 89/min, and respirations are 17/min. Physical examination is unremarkable. Laboratory testing is shown below: Hemoglobin: 10.8 g/dL Hematocrit: 32% Platelet count: 380,000/mm^3 Mean corpuscular volume: 118 µm^3 Reticulocyte count: 0.27% Leukocyte count: 9,900 cells/mm^3 with normal differential Erythrocyte sedimentation rate: 65 mm/h A colonoscopy is performed and demonstrates focal ulcerations with polypoid mucosal changes adjacent to normal appearing mucosa. A biopsy is obtained and shows ulcerations and acute and chronic inflammatory changes. Involvement of which of the following sites most likely explains this patient's clinical presentation?

A. Ileum (Correct Answer)
B. Jejunum
C. Colon
D. Gastric antrum
E. Gastric fundus

Explanation: ***Ileum*** - The patient's symptoms, including **right lower quadrant pain**, **fatigue**, **low-volume diarrhea**, **weight loss**, and **macrocytic anemia** (Hgb 10.8 g/dL, MCV 118 µm^3, low reticulocyte count), are highly suggestive of **Crohn's disease**, particularly with involvement of the **terminal ileum**. Ileal involvement can lead to **vitamin B12 malabsorption**, causing macrocytic anemia and neurological symptoms like "forgetfulness." - The colonoscopy findings of **focal ulcerations** with **polypoid mucosal changes adjacent to normal appearing mucosa** (skip lesions) and biopsy showing **acute and chronic inflammatory changes** are characteristic of **Crohn's disease**, which most commonly affects the terminal ileum and ileocecal region. *Jejunum* - While Crohn's disease can affect any part of the gastrointestinal tract, isolated jejunal involvement is relatively uncommon and typically presents with more diffuse abdominal pain rather than specific right lower quadrant pain. - Significant **vitamin B12 malabsorption** is less common with isolated jejunal involvement compared to ileal disease, as B12 is primarily absorbed in the terminal ileum. *Colon* - Colonic involvement in inflammatory bowel disease often presents with **bloody diarrhea**, which this patient denies. - Although **macrocytic anemia** can be seen in colonic Crohn's if there's significant ileal involvement or B12 deficiency from other causes, **right lower quadrant pain** is less specific for primary colonic inflammation, which would often be generalized or left-sided depending on the extent. *Gastric antrum* - Inflammation of the gastric antrum, such as from **gastritis** or **H. pylori infection**, would typically present with **epigastric pain**, nausea, and vomiting. - It would not explain the **right lower quadrant pain**, diarrhea, or the characteristic colonoscopic findings of **skip lesions and inflammatory changes** consistent with Crohn's disease. *Gastric fundus* - Disorders affecting the gastric fundus, such as **pernicious anemia** or chronic atrophic gastritis, can cause **vitamin B12 deficiency** and macrocytic anemia but do not typically present with significant **right lower quadrant pain** or diarrhea. - There would also be no corresponding colonic or ileal endoscopic findings as seen in this patient.

Question 23: A 25-year-old man comes to the physician with intermittent bloody diarrhea over the past 2 months. He has occasional abdominal pain. His symptoms have not improved over this time. He has no history of a serious illness and takes no medications. His blood pressure is 110/70 mm Hg, pulse is 75/min, respirations are 14/min, and temperature is 37.8°C (100.0°F). Deep palpation of the abdomen shows mild tenderness in the right lower quadrant. Colonoscopy shows diffuse erythema with a sandpaper pattern involving the rectosigmoid and descending colon, with normal mucosa of the rest of the colon. Biopsy shows involvement of the mucosal and submucosal layers with distortion of crypt architecture and crypt abscess formation. This patient is most likely to develop which of the following hepatobiliary diseases?

A. Primary sclerosing cholangitis (Correct Answer)
B. Cholangiocarcinoma
C. Hepatocellular carcinoma
D. Primary biliary cholangitis
E. Cholelithiasis

Explanation: ***Primary sclerosing cholangitis*** - This patient's presentation with **bloody diarrhea**, **abdominal pain**, and colonoscopic findings of **diffuse erythema** and **crypt abscesses** in the rectosigmoid and descending colon is highly suggestive of **ulcerative colitis**. - **Primary sclerosing cholangitis (PSC)** is strongly associated with **ulcerative colitis**, making it the most likely hepatobiliary complication. *Cholangiocarcinoma* - While **PSC** itself increases the risk of cholangiocarcinoma, it is a complication of long-standing PSC, not the direct hepatobiliary disease the patient is most likely to develop initially. - Cholangiocarcinoma is a **malignancy** of the bile ducts, and while possible eventually, PSC is the *primary* hepatobiliary disease associated with UC. *Hepatocellular carcinoma* - **Hepatocellular carcinoma (HCC)** is more commonly associated with chronic viral hepatitis (HBV, HCV), alcoholic liver disease, or non-alcoholic fatty liver disease (NAFLD) leading to cirrhosis. - It has no direct and strong epidemiological association with **ulcerative colitis** or **inflammatory bowel disease** in the same way PSC does. *Primary biliary cholangitis* - **Primary biliary cholangitis (PBC)** is an autoimmune disease primarily affecting small intrahepatic bile ducts, characterized by **anti-mitochondrial antibodies (AMA)**. - It is not specifically associated with **ulcerative colitis** as **PSC** is; the major association is between PSC and IBD. *Cholelithiasis* - **Cholelithiasis (gallstones)** can occur in patients with Crohn's disease due to impaired ileal absorption of bile salts, but it is less commonly a direct complication of ulcerative colitis. - While possible in the general population, it is not the *most likely* specific hepatobiliary complication directly linked to ulcerative colitis.

Question 24: A 22-year-old man presents to the emergency department with abdominal pain. The patient states that he has had right lower quadrant abdominal pain for "a while now". The pain comes and goes, and today it is particularly painful. The patient is a college student studying philosophy. He drinks alcohol occasionally and is currently sexually active. He states that sometimes he feels anxious about school. The patient's father died of colon cancer at the age of 55, and his mother died of breast cancer when she was 57. The patient has a past medical history of anxiety and depression which is not currently treated. Review of systems is positive for bloody diarrhea. His temperature is 99.5°F (37.5°C), blood pressure is 100/58 mmHg, pulse is 120/min, respirations are 17/min, and oxygen saturation is 98% on room air. Cardiopulmonary exam is within normal limits. Abdominal exam reveals diffuse tenderness. A fecal occult blood test is positive. Which of the following is the most likely diagnosis?

A. Irritable bowel syndrome
B. Colon cancer
C. Appendicitis
D. Infectious colitis
E. Inflammatory bowel disease (IBD) (Correct Answer)

Explanation: ***Inflammatory bowel disease (IBD)*** - The patient's presentation with **recurrent right lower quadrant pain**, **bloody diarrhea**, a **positive fecal occult blood test**, and a family history concerning for GI issues (colon cancer in father) in a young adult is highly suggestive of IBD, specifically **Crohn's disease** due to the RLQ pain location. - His history of anxiety and depression is common in IBD patients, and the elevated pulse with mild hypotension suggests **volume depletion** from bloody diarrhea, a common complication. *Irritable bowel syndrome* - While IBS can cause recurrent abdominal pain, it is characterized by **functional bowel changes** and typically does not present with **bloody diarrhea** or a positive fecal occult blood test. - IBS symptoms are often relieved by defecation and are not usually associated with significant systemic inflammation or blood loss. *Colon cancer* - Colon cancer is less likely in a **22-year-old** presenting with these acute symptoms, despite the family history, as it typically affects older individuals. - While it can cause bloody stools and abdominal pain, the **recurrent nature** and acute presentation with bloody diarrhea are more classic for IBD in this age group. *Appendicitis* - Appendicitis presents with acute, **migratory right lower quadrant pain** that typically progresses and worsens over hours to a day, often with fever and leukocytosis. - The given history of pain for "**a while now**" and bloody diarrhea makes appendicitis an unlikely primary diagnosis. *Infectious colitis* - Infectious colitis can cause abdominal pain and bloody diarrhea, but it's usually **acute in onset** without a long history of recurrent symptoms. - While possible, the **recurrent nature** of the pain and bloody diarrhea for "**a while now**" makes a chronic condition like IBD more probable.

Question 25: A 33-year-old woman comes to the physician because of a 4-month history of intermittent lower abdominal cramps associated with diarrhea, bloating, and mild nausea. During this period, she has had a 5-kg (11-lb) weight loss. She feels like she cannot fully empty her bowels. She has no history of serious illness. She has a high-fiber diet. Her father is of Ashkenazi Jewish descent. She appears well. Her temperature is 36.9°C (98.5°F), pulse is 90/min, and blood pressure is 130/90 mm Hg. The lungs are clear to auscultation. Cardiac examination shows no murmurs, rubs, or gallops. Abdominal examination shows mild tenderness to palpation in the right lower quadrant without guarding or rebound. Bowel sounds are normal. Test of the stool for occult blood is negative. Her hemoglobin concentration is 10.5 g/dL, leukocyte count is 12,000 mm3, platelet count is 480,000 mm3, and erythrocyte sedimentation rate is 129 mm/h. A barium enema shows ulceration and narrowing of the right colon. Which of the following is the most likely diagnosis?

A. Celiac disease
B. Crohn disease (Correct Answer)
C. Diverticulitis
D. Ulcerative colitis
E. Intestinal carcinoid tumor

Explanation: ***Crohn disease*** - The patient presents with **intermittent abdominal cramps**, diarrhea, bloating, nausea, and significant **weight loss**, which are classic symptoms of **inflammatory bowel disease (IBD)**. - **Anemia (Hb 10.5 g/dL)**, **leukocytosis (12,000/mm³)**, **thrombocytosis (480,000/mm³)**, and a **markedly elevated ESR (129 mm/h)** further support active inflammation. The **barium enema showing ulceration and narrowing of the right colon** is highly characteristic of **Crohn disease**, which commonly affects the **terminal ileum and right colon** with **skip lesions** and **transmural inflammation** leading to strictures and ulcerations. *Celiac disease* - While celiac disease can cause diarrhea, bloating, and weight loss, it is primarily a disease of the **small intestine** triggered by **gluten exposure** and does not typically present with the **segmental ulceration and narrowing** seen on barium enema in the right colon. - Celiac disease would also not explain the significant systemic inflammatory markers such as **elevated ESR**, leukocytosis, and thrombocytosis to this degree. *Diverticulitis* - Diverticulitis typically presents with **left lower quadrant pain**, fever, and changes in bowel habits, but it usually involves the **sigmoid colon** and is characterized by outpouchings, not diffuse ulceration and narrowing of the right colon. - **Weight loss** and the chronic, intermittent nature of symptoms with **right-sided involvement** are less typical for diverticulitis. *Ulcerative colitis* - Ulcerative colitis is another form of IBD, but it characteristically causes **continuous inflammation** that starts in the **rectum** and extends proximally through the colon, primarily affecting the **mucosa** and submucosa. - **Right-sided colonic involvement with narrowing and discrete ulcerations** as seen on barium enema is more indicative of Crohn disease than ulcerative colitis, which typically presents with bloody diarrhea due to diffuse inflammation. *Intestinal carcinoid tumor* - An intestinal carcinoid tumor might cause abdominal pain, diarrhea, and weight loss, especially if it leads to bowel obstruction, but these symptoms are usually accompanied by **carcinoid syndrome** (e.g., flushing, bronchospasm, valvular heart disease). - The imaging findings of **ulceration and narrowing** are not typical for a carcinoid tumor, and the marked inflammatory markers point towards an inflammatory process rather than a neoplastic one.

Question 26: A 39-year-old woman presents to your office with 4 days of fever, sore throat, generalized aching, arthralgias, and tender nodules on both of her shins that arose in the last 48 hours. Her medical history is negative for disease and she does not take oral contraceptives or any other medication regularly. The physical examination reveals the vital signs that include body temperature 38.5°C (101.3°F), heart rate 85/min, blood pressure 120/65 mm Hg, tender and enlarged submandibular lymph nodes, and an erythematous, edematous, and swollen pharynx with enlarged tonsils and a patchy white exudate on the surface. She is not pregnant. Examination of the lower limbs reveals erythematous, tender, immobile nodules on both shins. You do not identify ulcers or similar lesions on other areas of her body. What is the most likely diagnosis in this patient?

A. Erythema nodosum (Correct Answer)
B. Henoch-Schönlein purpura
C. Cellulitis
D. Erythema induratum
E. Cutaneous polyarteritis nodosa

Explanation: ***Erythema nodosum*** - The patient presents with **tender nodules on both shins** (erythema nodosum), accompanied by fever, sore throat, arthralgias, and enlarged tonsils with exudate, all of which are consistent with an **underlying infection** (likely streptococcal pharyngitis) triggering erythema nodosum. - Erythema nodosum is the most common form of **panniculitis** and often presents as an acute inflammatory reaction to various systemic diseases, infections (e.g., streptococcal pharyngitis, tuberculosis), drugs, or inflammatory conditions. *Henoch-Schönlein purpura* - Henoch-Schönlein purpura (HSP) typically presents with a **palpable purpura** (non-blanching lesions), often predominantly on the lower extremities and buttocks, and is associated with **abdominal pain**, **arthralgia**, and **renal involvement**. - The patient's lesions are described as **tender nodules**, not purpura, and there is no mention of abdominal pain or signs of renal disease. *Cellulitis* - Cellulitis is a **bacterial infection** of the deeper dermis and subcutaneous tissue, characterized by **spreading redness, warmth, pain, and swelling** that is typically unilateral. - The lesions here are **discrete, tender nodules** on both shins, which is inconsistent with the diffuse, spreading inflammation of cellulitis. *Erythema induratum* - Erythema induratum, also a form of panniculitis, typically presents with **tender, erythematous nodules or plaques** on the **calves**, often leading to ulceration, and is historically associated with tuberculosis. - While it causes nodules, the presentation here, especially the acute onset with a clear infectious prodrome and location on the shins without ulceration, is more characteristic of erythema nodosum than erythema induratum. *Cutaneous polyarteritis nodosa* - Cutaneous polyarteritis nodosa (CPN) is a form of **small-to-medium vessel vasculitis** that usually presents with **tender subcutaneous nodules**, **livedo reticularis**, ulcerations, and sometimes digital gangrene. - While CPN can cause nodules, the patient's prominent symptoms of pharyngitis with exudate and generalized arthralgias point more strongly to an infectious trigger of erythema nodosum rather than a primary vasculitic process.

Question 27: A 28-year-old woman presents to the clinic with complaints of occasional low-grade fever and joint pain for 1 month. She also complains of morning stiffness in the proximal interphalangeal joints of both hands, which lasts for 5 to 10 minutes. She recently noticed a pink rash on her nose and cheekbones. Her family history is significant for similar complaints in her mother. She is not taking any medications. On examination, her temperature is 37.6°C (99.6°F), pulse is 74/min, blood pressure is 110/70 mm Hg, and respirations are 18/min. Aphthous ulcers are noted on her oral mucosa. Which of the following tests would be most specific for confirming the diagnosis in this patient?

A. Antinuclear antibodies (ANA)
B. Anti-topoisomerase (anti-Scl 70) antibodies
C. Anti-double stranded DNA (dsDNA) antibodies (Correct Answer)
D. Anti-Ro antibodies
E. Anti-histone antibodies

Explanation: ***Anti-double stranded DNA (dsDNA) antibodies*** - The patient's symptoms (low-grade fever, joint pain, morning stiffness, malar rash, oral ulcers, and family history) are highly suggestive of **Systemic Lupus Erythematosus (SLE)**. - **Anti-dsDNA antibodies** are highly specific for SLE and are included in the diagnostic criteria, often correlating with disease activity and **lupus nephritis**. *Antinuclear antibodies (ANA)* - While **ANA** is a very sensitive screening test for SLE (positive in >95% of cases), it is not specific, as it can be positive in other autoimmune diseases and even in healthy individuals. - A positive ANA result prompts further testing with more specific antibodies to confirm an SLE diagnosis. *Anti-topoisomerase (anti-Scl 70) antibodies* - **Anti-Scl 70 antibodies** are highly specific for **systemic sclerosis (scleroderma)**, particularly the diffuse cutaneous form. - The patient's presentation does not describe the skin thickening, Raynaud's phenomenon, or other characteristic features of scleroderma. *Anti-Ro antibodies* - **Anti-Ro (SSA) antibodies** are primarily associated with **Sjögren's syndrome**, and can also be found in a subset of SLE patients, particularly those with subacute cutaneous lupus or neonatal lupus. - They are not as specific for SLE as anti-dsDNA antibodies, and the patient's symptoms are more directly indicative of classic SLE. *Anti-histone antibodies* - **Anti-histone antibodies** are strongly associated with **drug-induced lupus**, which is not suggested by the patient's history as she is not taking any medications. - While they can be present in some cases of idiopathic SLE, they are not the most specific marker for confirming the diagnosis in this context.

Question 28: A 35-year-old woman comes to the physician because of a 3-month history of worsening fatigue. She has difficulty concentrating at work despite sleeping well most nights. Three years ago, she was diagnosed with Crohn disease. She has about 7 non-bloody, mildly painful bowel movements daily. Her current medications include 5-aminosalicylic acid and topical budesonide. She does not smoke or drink alcohol. She appears pale. Her temperature is 37.9°C (100.2°F), pulse is 92/min, and blood pressure is 110/65 mmHg. The abdomen is diffusely tender to palpation, with no guarding. Laboratory results show: Hemoglobin 10.5 g/dL Mean corpuscular volume 83 μm3 Reticulocytes 0.2 % Platelets 189,000/mm3 Serum Iron 21 μg/dL Total iron binding capacity 176 μg/dL (N=240–450) A blood smear shows anisocytosis. Which of the following is the most appropriate next step in treatment?

A. Red blood cell transfusion
B. Oral iron supplementation
C. Subcutaneous erythropoietin injection
D. Oral vitamin B12 supplementation
E. Oral prednisone therapy (Correct Answer)

Explanation: ***Oral prednisone therapy*** - The patient's symptoms (worsening fatigue, difficulty concentrating), signs (fever, diffuse abdominal tenderness), and lab findings (**anemia**, **active inflammation**) indicate a **moderate to severe flare of Crohn disease**. - She has **7 bowel movements daily** and is inadequately controlled on 5-aminosalicylic acid and topical budesonide, indicating need for escalation of therapy. - **Systemic corticosteroids like prednisone** are the mainstay for inducing remission in a moderate to severe Crohn disease flare when aminosalicylates and topical steroids are insufficient. - Treating the underlying inflammation will also improve the **anemia of chronic disease**. *Red blood cell transfusion* - While the patient has **anemia (Hb 10.5 g/dL)**, it is not severe enough to warrant an immediate **red blood cell transfusion**. - Transfusions are typically reserved for **severe, symptomatic anemia** (Hb <7 g/dL in stable patients) or those with acute hemodynamic instability or active bleeding, which is not present here. - The underlying cause (active Crohn's flare) should be treated first. *Oral iron supplementation* - The patient has **anemia of chronic disease** as evidenced by **low iron, LOW TIBC (176 μg/dL)**, normocytic anemia, and low reticulocytes in the setting of active inflammation. - In **anemia of chronic disease**, ferritin is typically elevated (acute phase reactant) and hepcidin levels are high, which **blocks iron absorption and utilization**. - **Oral iron supplementation** would be largely ineffective in the context of active inflammation. The priority is to resolve the inflammation with corticosteroids, which will improve iron utilization. - Note: If TIBC were HIGH, it would suggest iron deficiency anemia instead. *Subcutaneous erythropoietin injection* - **Erythropoietin** is primarily used for **anemia associated with chronic kidney disease** or specific cases of anemia of chronic disease unresponsive to other measures. - It would not address the underlying **active inflammation from Crohn disease** which is the primary driver of her current symptoms and anemia. - Treating the Crohn's flare is the appropriate first step. *Oral vitamin B12 supplementation* - While Crohn disease, particularly involving the terminal ileum, can lead to **vitamin B12 deficiency**, her **mean corpuscular volume (MCV)** is normal (83 μm3), indicating a **normocytic anemia**, not the macrocytic anemia (MCV >100) typical of B12 deficiency. - Furthermore, addressing the active inflammation is the most urgent step to improve her overall condition and resolve the anemia.

Question 29: A 36-year-old man comes to the emergency department for the evaluation of recurrent bloody diarrhea for 4 weeks. During this time, he has also had intermittent abdominal pain. His symptoms have worsened over the past 2 days and he has also had fever and several episodes of nonbloody vomiting. He was diagnosed with ulcerative colitis three years ago but has had difficulty complying with his drug regimen. His temperature is 38.8°C (100.9°F), pulse is 112/min and regular, and blood pressure is 90/50 mm Hg. Abdominal examination shows a distended abdomen with no guarding or rebound; bowel sounds are hypoactive. Hemoglobin concentration is 10.1 g/dL, leukocyte count is 15,000/mm3, and erythrocyte sedimentation rate is 50 mm/h. Fluid resuscitation is initiated. In addition to complete bowel rest, which of the following is the most appropriate next step in the management of this patient?

A. Abdominal x-ray (Correct Answer)
B. IV metronidazole and rectal vancomycin
C. Colonoscopy
D. Topical sulfasalazine and oral prednisolone
E. Double-contrast barium enema

Explanation: ***Abdominal x-ray*** - This patient presents with **severe ulcerative colitis** symptoms (bloody diarrhea, abdominal pain, fever, tachycardia, hypotension, leukocytosis, elevated ESR) and signs of **toxic megacolon** (distended abdomen, hypoactive bowel sounds). An **abdominal x-ray** is crucial for diagnosing toxic megacolon by revealing colonic dilation (>6 cm). - Early identification of toxic megacolon is critical as it carries a high risk of **perforation** and requires urgent intervention; fluid resuscitation and bowel rest are initial steps, but imaging must confirm the diagnosis before proceeding with medical or surgical therapy. *IV metronidazole and rectal vancomycin* - While **antibiotics** like metronidazole might be used in severe colitis to cover for bacterial translocation, the specific combination with rectal vancomycin suggests treatment for *Clostridioides difficile* infection. Although possible, the immediate priority in suspected toxic megacolon is to rule out perforation and assess colonic dilation. - *C. difficile* infection can exacerbate UC, but an abdominal x-ray is still needed first to assess for **toxic megacolon** and its complications before specific infection treatment. *Colonoscopy* - **Colonoscopy** is generally **contraindicated** in acute, severe ulcerative colitis and suspected toxic megacolon due to the high risk of **perforation** of the inflamed bowel. - Diagnostic evaluation should focus on less invasive methods to assess the severity and complications, such as **imaging**. *Topical sulfasalazine and oral prednisolone* - **Sulfasalazine** and **prednisolone** are used to treat active ulcerative colitis. However, topical sulfasalazine is not potent enough for severe, systemic symptoms, and while oral prednisolone is used for flares, it's insufficient for a patient with signs of **toxic megacolon** and hemodynamic instability. - This patient's condition warrants **aggressive intravenous steroids** (e.g., hydrocortisone or methylprednisolone) and close monitoring in an intensive care setting, but the immediate step is diagnostic imaging. *Double-contrast barium enema* - A **barium enema** is **contraindicated** in patients with severe inflammatory bowel disease, especially with suspected toxic megacolon, due to the high risk of **perforation** and the potential to worsen the patient's condition. - It also provides less immediate and detailed information about colonic dilation and perforation compared to a plain abdominal x-ray or CT scan.

Question 30: A 29-year-old man presents to clinic with a complaint of fatigue that has developed over the past 6 months. Upon questioning, he endorses abdominal pain, non-bloody diarrhea, and decreased appetite over the past year. He denies recent travel outside of the country or eating uncooked meats. On exam, his temperature is 99.0°F (37.2°C), blood pressure is 126/78 mmHg, pulse is 93/min, and respirations are 12/min. Notably, the abdominal exam is unremarkable aside from some tenderness to palpation near the umbilicus. His colonoscopy demonstrates perianal inflammation with a normal rectum, and biopsies of suspicious lesions in the transverse colon reveal transmural inflammation. Which one of the following is most strongly associated with the patient’s condition?

A. Positive serum transglutaminase antibodies
B. Kidney stones (Correct Answer)
C. Endocarditis
D. Colorectal cancer
E. Hemolytic anemia

Explanation: ***Kidney stones*** - Patients with **Crohn's disease**, particularly those with ileal involvement, are at increased risk for **calcium oxalate kidney stones** due to increased oxalate absorption. - In Crohn's disease, fat malabsorption occurs because bile salts are not reabsorbed in the inflamed terminal ileum. This leads to free fatty acids in the colon that bind calcium, leaving oxalate unbound and available for absorption. The excess oxalate is then excreted in urine, promoting calcium oxalate stone formation. - This is one of the most well-established extraintestinal complications of Crohn's disease. *Positive serum transglutaminase antibodies* - These antibodies are a hallmark of **celiac disease**, which is characterized by villous atrophy in the small intestine due to gluten sensitivity. - The patient's clinical presentation and colonoscopy findings (transmural inflammation, perianal disease, skip lesions) are pathognomonic for Crohn's disease, not celiac disease. *Endocarditis* - **Endocarditis** is an infection of the heart valves, typically caused by bacteremia, and is not a recognized association with Crohn's disease. - While chronic inflammatory conditions can have cardiovascular effects, endocarditis is not a characteristic or strong complication of Crohn's disease. *Colorectal cancer* - While patients with **ulcerative colitis** have a significantly increased risk of colorectal cancer (especially with pancolitis and longer disease duration), the risk in **Crohn's disease** is lower and less direct. - Crohn's disease can increase colorectal cancer risk with extensive colonic involvement, but this patient's presentation shows predominantly small bowel and perianal disease, making kidney stones a much stronger and more immediate association. *Hemolytic anemia* - **Hemolytic anemia** is not a characteristic complication of Crohn's disease. - Anemia in Crohn's disease is more commonly due to **iron deficiency** from chronic blood loss or malabsorption, or **anemia of chronic disease** from chronic inflammation, rather than hemolysis.

Question 31: A 33-year-old woman presents to the clinic complaining of yellowish discoloration of her skin and eyes, mild fever, and body aches. She has had this problem for 6 months, but it has become worse over the past few weeks. She also complains of repeated bouts of bloody diarrhea and abdominal pain. The past medical history is noncontributory. She takes no medication. Both of her parents are alive with no significant disease. She works as a dental hygienist and drinks wine occasionally on weekends. Today, the vital signs include blood pressure 110/60 mm Hg, pulse rate 90/min, respiratory rate 19/min, and temperature 36.6°C (97.8°F). On physical examination, she appears uncomfortable. The skin and sclera are jaundiced. The heart has a regular rate and rhythm, and the lungs are clear to auscultation bilaterally. The abdomen is soft with mild hepatosplenomegaly. There is no tenderness or rebound tenderness. The digital rectal examination reveals blood and mucus in the rectal vault. Laboratory studies show: Serum sodium 140 mEq/L Serum potassium 3.8 mEq/L Alanine aminotransferase (ALT) 250 U/L Aspartate aminotransferase (AST) 170 U/L Alkaline phosphatase (ALP) 120 U/L Which of the following antibodies would you expect to find in this patient?

A. Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) (Correct Answer)
B. Anti-double stranded DNA (anti-dsDNA)
C. Anti-mitochondrial antibody
D. Anti-cyclic citrullinated peptide (anti-CCP)
E. Anti-endomysial IgA

Explanation: ***Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA)*** - The patient presents with **primary sclerosing cholangitis (PSC)** in the setting of **inflammatory bowel disease (IBD)**, most likely ulcerative colitis given the bloody diarrhea and rectal bleeding. - The combination of **cholestatic liver disease** (jaundice, elevated ALP) and **IBD** is pathognomonic for PSC, as **60-80% of PSC patients have concurrent IBD** (predominantly UC). - **p-ANCA is positive in 60-80% of PSC patients** and 70-80% of UC patients, making it the expected antibody in this clinical scenario. *Anti-double stranded DNA (anti-dsDNA)* - Anti-dsDNA antibodies are highly specific for **Systemic Lupus Erythematosus (SLE)**. - While SLE can cause hepatitis and serositis, it does not typically present with **cholestatic jaundice combined with bloody diarrhea**. The clinical picture here does not fit SLE. *Anti-mitochondrial antibody* - Anti-mitochondrial antibodies (AMAs) are the hallmark of **primary biliary cholangitis (PBC)**, found in >95% of cases. - While PBC also causes cholestatic liver disease, **the presence of inflammatory bowel disease strongly favors PSC over PBC**, as IBD is seen in 60-80% of PSC patients but is **NOT a recognized association with PBC**. - PBC typically presents in middle-aged women with fatigue, pruritus, and cholestasis, but without concurrent IBD. *Anti-cyclic citrullinated peptide (anti-CCP)* - Anti-CCP antibodies are highly specific for **rheumatoid arthritis (RA)**. - The patient's symptoms—jaundice, hepatosplenomegaly, and bloody diarrhea—are inconsistent with RA, which primarily involves **inflammatory polyarthritis** of small joints. *Anti-endomysial IgA* - Anti-endomysial antibodies (EMA) are characteristic of **celiac disease**. - Celiac disease presents with malabsorption, chronic diarrhea (usually non-bloody), and may have mild transaminitis, but does **NOT** typically cause **significant cholestatic jaundice, hepatosplenomegaly, or bloody diarrhea** as seen in this patient.

Question 32: A 27-year-old female has a history of periodic bloody diarrhea over several years. Colonoscopy shows sigmoid colon inflammation, and the patient complains of joint pain in her knees and ankles. You suspect inflammatory bowel disease. Which of the following would suggest a diagnosis of Crohn disease:

A. Jaundice
B. Mucosal and submucosal ulcerations
C. Perianal fistula (Correct Answer)
D. Loss of large bowel haustra
E. Left lower quadrant pain

Explanation: ***Perianal fistula*** - The presence of a **perianal fistula** is highly characteristic of **Crohn disease** due to its **transmural inflammation**, which can extend through the bowel wall and form tracts to the skin. - While other inflammatory bowel disease (IBD) symptoms like bloody diarrhea and joint pain are present, a fistula specifically points towards Crohn disease rather than ulcerative colitis. *Jaundice* - **Jaundice** is not a typical manifestation of Crohn disease itself, though it can occur as a complication if there is associated **primary sclerosing cholangitis (PSC)**, which is more commonly linked with **ulcerative colitis**. - It would suggest a primary liver issue or biliary obstruction, rather than directly supporting a diagnosis of Crohn disease. *Mucosal and submucosal ulcerations* - While **ulcerations** are a feature of both ulcerative colitis and Crohn disease, the description of **mucosal and submucosal ulcerations** is not specific enough to differentiate between them. - In Crohn disease, ulcers tend to be **scattered** and **deep ("cobblestoning")**, potentially extending transmurally, whereas in ulcerative colitis, they are typically more **superficial** and **continuous**. *Loss of large bowel haustra* - **Loss of haustra**, also known as **"lead pipe" appearance**, is a characteristic finding in chronic **ulcerative colitis** due to continuous inflammation and fibrosis, leading to a straightened appearance of the colon. - This finding is less typical for Crohn disease, which often has **skip lesions** and can involve any part of the gastrointestinal tract. *Left lower quadrant pain* - **Left lower quadrant pain** can be associated with inflammation in the **descending or sigmoid colon**, which can occur in both Crohn disease and ulcerative colitis. - Therefore, this symptom is **non-specific** and does not help to differentiate between the two conditions.

Question 33: An 18-year-old man presents with bloody diarrhea and weight loss. He undergoes endoscopic biopsy which shows pseudopolyps. Biopsies taken during the endoscopy show inflammation only involving the mucosa and submucosa. He is diagnosed with an inflammatory bowel disease. Which of the following characteristics was most likely present?

A. Cobblestone mucosa
B. Skip lesions
C. Fistulas and strictures
D. Noncaseating granuloma
E. Rectal involvement (Correct Answer)

Explanation: **_Rectal involvement_** - The description of **bloody diarrhea** and **pseudopolyps** on endoscopy, along with inflammation limited to the **mucosa and submucosa**, is highly characteristic of **ulcerative colitis (UC)**. UC invariably involves the rectum and extends proximally in a continuous fashion. - The presence of **pseudopolyps** is common in UC due to cycles of mucosal ulceration and regeneration. *Cobblestone mucosa* - **Cobblestone mucosa** is a classic endoscopic finding in **Crohn's disease**, resulting from deep ulcerations interspersed with islands of edematous, non-ulcerated mucosa. - This feature points to a transmural pattern of inflammation, which is inconsistent with the superficial inflammation confined to the **mucosa and submucosa** described. *Skip lesions* - **Skip lesions** refer to discontinuous areas of inflammation separated by healthy tissue, a hallmark feature of **Crohn's disease**. - **Ulcerative colitis** (implied by the superficial inflammation) is characterized by continuous inflammation extending proximally from the rectum without skipped areas. *Fistulas and strictures* - **Fistulas** (abnormal connections between organs or to the skin) and **strictures** (narrowing of the intestinal lumen) are complications typically associated with **Crohn's disease**, due to its **transmural inflammation**. - These are rare in **ulcerative colitis**, which primarily affects the superficial layers of the colon. *Noncaseating granuloma* - The presence of **noncaseating granulomas** on biopsy is a key histological feature distinguishing **Crohn's disease** from ulcerative colitis. - The inflammation described as restricted to the **mucosa and submucosa** makes granulomas less likely, as they often imply a transmural process.

Question 34: A 27-year-old male presents to his primary care physician complaining of pain with urination and eye redness. He reports that he developed these symptoms approximately one week ago. He also has noticed left knee and right heel pain that started a few days ago. He denies any recent trauma. He had an episode of abdominal pain and diarrhea ten days ago that resolved. He has otherwise felt well. On exam, he walks with a limp and his conjunctivae are erythematous. Laboratory findings are notable for an elevated erythrocyte sedimentation rate (ESR) and elevated C-reactive protein (CRP). Which of the following is most likely associated with this patient’s condition?

A. Anti-centromere antibody
B. HLA-B27 haplotype (Correct Answer)
C. Anti-cyclic citrullinated peptide (anti-CCP) antibody
D. HLA-DR4 haplotype
E. Rheumatoid factor

Explanation: ***HLA-B27 haplotype*** - The patient presents with symptoms of **urethritis** (pain with urination), **conjunctivitis** (eye redness), and **arthritis** (knee and heel pain), which is the classic triad of **Reactive Arthritis** - **Reactive arthritis** is strongly associated with the presence of the **HLA-B27 haplotype**, especially following gastrointestinal or genitourinary infections. *Anti-centromere antibody* - This antibody is associated with **limited cutaneous systemic sclerosis** (CREST syndrome) characterized by calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasias. - The patient's symptoms do not align with systemic sclerosis. *Anti-cyclic citrullinated peptide (anti-CCP) antibody* - **Anti-CCP antibodies** are highly specific for **rheumatoid arthritis**, which primarily affects the small joints of the hands and feet symmetrically and does not typically present with conjunctivitis or urethritis. - The patient's presentation with an acute, asymmetric arthritis following an infection is not consistent with rheumatoid arthritis. *HLA-DR4 haplotype* - The **HLA-DR4 haplotype** is primarily associated with **rheumatoid arthritis**, a chronic inflammatory autoimmune disease that differs significantly in presentation from the patient's acute symptoms. - This patient's symptoms are more indicative of a seronegative spondyloarthropathy, not rheumatoid arthritis. *Rheumatoid factor* - **Rheumatoid factor (RF)** is an autoantibody found in many patients with **rheumatoid arthritis**, but it is also present in other conditions and can be negative in some RA cases. - While it indicates systemic inflammation, it is not specific to the patient's constellation of symptoms, which point more directly to a reactive process.

Question 35: A 34-year-old man presents to his dermatologist with white scaly papules and plaques on his extensor arms, elbows, knees, and shins. Scaly and flaky eruptions are also present on his ears, eyebrows, and scalp. He describes the lesions as being itchy and irritating. When the scales are scraped away, pinpoint bleeding is noted. His vital signs are unremarkable, and physical examination is otherwise within normal limits. Which of the following is the best initial test for this patient’s condition?

A. No tests are necessary (Correct Answer)
B. Serum autoantibodies
C. Plain film X-rays of the hands and feet
D. Skin biopsy
E. Wood’s lamp

Explanation: **No tests are necessary** - The patient's presentation with **white scaly papules and plaques** on extensor surfaces (elbows, knees, shins), along with involvement of the ears, eyebrows, and scalp, are classic signs of **psoriasis**. - The phenomenon of **pinpoint bleeding** upon scraping the scales (Auspitz sign) is highly distinctive for psoriasis, making additional diagnostic tests initially unnecessary. *Serum autoantibodies* - This test is typically used to diagnose **autoimmune connective tissue diseases** like lupus or rheumatoid arthritis, which have different clinical presentations. - Psoriasis is a T-cell mediated autoimmune disease, but specific serum autoantibodies are not used for its primary diagnosis. *Plain film X-rays of the hands and feet* - X-rays are used to assess **joint damage** in conditions like psoriatic arthritis, which is a complication of psoriasis. - However, the patient's current presentation describes only skin lesions, so joint imaging is not the best initial diagnostic step. *Skin biopsy* - While a **skin biopsy** can confirm psoriasis, the clinical picture here is so characteristic that a biopsy is generally reserved for **atypical presentations** or when the diagnosis is uncertain. - It is not the *best initial test* when the diagnosis is clear clinically. *Wood’s lamp* - A **Wood's lamp** (UV light) is primarily used to detect **fungal infections** (e.g., tinea) or pigmentation disorders. - It does not aid in the diagnosis of psoriasis, which has a distinct morphology visible to the naked eye.

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