A 47-year-old woman presents with weakness, shortness of breath, and lightheadedness. She says her symptoms onset gradually 4 months ago and have progressively worsened. Past medical history is significant for a long history of menorrhagia secondary to uterine fibroids. Her vital signs include: temperature 36.9°C (98.4°F), blood pressure 135/82 mm Hg, and pulse 97/min. Physical examination is unremarkable. Laboratory test results are shown below:
Hemoglobin 9.2 g/dL
Mean corpuscular volume (MCV) 74 μm3
Mean corpuscular hemoglobin (MCH) 21 pg/cell
Reticulocyte count 0.4 %
Serum ferritin 10 ng/mL
Which of the following is a specific feature of this patient's condition?
Q62
A 32-year-old male patient presents to a medical office requesting screening for colorectal cancer. He currently has no symptoms and his main concern is that his father was diagnosed with colorectal cancer at 55 years of age. What screening strategy would be the most appropriate?
Q63
A 55-year-old female presents to clinic with recurrent episodes of abdominal discomfort and pain for the past month. She reports that the pain occurs 2-3 hours after meals, usually at midnight, and rates it as moderate to severe in intensity when it occurs. She also complains of being fatigued all the time. Past medical history is insignificant. She is an office secretary and says that the job has been very stressful recently. Her temperature is 98.6°F (37.0°C), respiratory rate is 15/min, pulse is 67/min, and blood pressure is 122/98 mm Hg. Her BMI is 34. A physical examination reveals conjunctival pallor and mild tenderness over her epigastric region. Blood tests show:
Hb%: 10 gm/dL
Total count (WBC): 11,000 /mm3
Differential count:
Neutrophils: 70%
Lymphocytes: 25%
Monocytes: 5%
ESR: 10 mm/hr
Which of the following is the most likely diagnosis?
Q64
A 72-year-old man presents to his primary care physician with the symptom of generalized malaise over the last month. He also has abdominal pain that has been persistent and not relieved by ibuprofen. He has unintentionally lost 22 pounds recently. During this time, the patient has experienced intermittent diarrhea when he eats large meals. The patient has a past medical history of alcohol use, obesity, diabetes mellitus, hypertension, IV drug use, and asthma. His current medications include disulfiram, metformin, insulin, atorvastatin, lisinopril, albuterol, and an inhaled corticosteroid. The patient attends weekly Alcoholics Anonymous meetings and was recently given his two week chip for not drinking. His temperature is 99.5°F (37.5°C), blood pressure is 100/57 mmHg, pulse is 88/min, respirations are 11/min, and oxygen saturation is 98% on room air. The patient's abdomen is tender to palpation, and the liver edge is palpable 2 cm inferior to the rib cage. Neurologic exam demonstrates gait that is not steady. Which of the following is the best initial diagnostic test for this patient?
Q65
A 44-year-old woman comes to the emergency department because of a 10-hour history of severe nausea and abdominal pain that began 30 minutes after eating dinner. The pain primarily is in her right upper quadrant and occasionally radiates to her back. She has a history of type 2 diabetes mellitus and hypercholesterolemia. Current medications include metformin and atorvastatin. She is 163 cm (5 ft 4 in) tall and weighs 91 kg (200 lb); BMI is 34 kg/m2. Her temperature is 38.8°C (101.8°F), pulse is 100/min, respirations are 14/min, and blood pressure is 150/76 mm Hg. Abdominal examination shows right upper quadrant tenderness with guarding. A bedside ultrasound shows a gall bladder wall measuring 6 mm, pericholecystic fluid, sloughing of the intraluminal membrane, and a 2 x 2-cm stone at the neck of the gallbladder. The common bile duct appears unremarkable. Laboratory studies show leukocytosis and normal liver function tests. Intravenous fluids are started, and she is given ketorolac for pain control. Which of the following is the most appropriate next step in management?
Q66
A 45-year-old man presents to the office for evaluation of pruritic skin lesions, which he has had for 1 month on his elbows and knees. He has been using over-the-counter ointments, but they have not helped. He has not seen a healthcare provider for many years. He has no known allergies. His blood pressure is 140/80 mm Hg, his pulse is 82 beats per minute, his respirations are 18 breaths per minute, and his temperature is 37.2°C (98.9°F). On examination, clustered vesicular lesions are noted on both elbows and knees. Cardiovascular and pulmonary exams are unremarkable. Which of the following would most likely be associated with this patient’s condition?
Q67
A 59-year-old man presents to the emergency department with a 6 day history of persistent fevers. In addition, he has noticed that he feels weak and sometimes short of breath. His past medical history is significant for congenital heart disease though he doesn't remember the specific details. He has been unemployed for the last 3 years and has been occasionally homeless. Physical exam reveals nailbed splinter hemorrhages and painful nodes on his fingers and toes. Blood cultures taken 12 hours apart grow out Streptococcus gallolyticus. Which of the following is most likely associated with this patient's disease?
Q68
A 23-year-old woman comes to the physician because of a 2-month history of diarrhea, flatulence, and fatigue. She reports having 3–5 episodes of loose stools daily that have an oily appearance. The symptoms are worse after eating. She also complains of an itchy rash on her elbows and knees. A photograph of the rash is shown. Further evaluation of this patient is most likely to show which of the following findings?
Q69
A 28-year-old male comes to the physician for worsening back pain. The pain began 10 months ago, is worse in the morning, and improves with activity. He has also had bilateral hip pain and difficulty bending forward during exercise for the past 3 months. He has celiac disease and eats a gluten-free diet. Examination shows a limited range of spinal flexion. Flexion, abduction, and external rotation of both hips produces pain. Further evaluation of this patient is most likely to show which of the following laboratory findings?
Q70
A 13-year-old girl is admitted to the hospital due to muscle weakness, pain, and arthralgia in her wrist joints. The patient says, "I am having trouble walking home after school, especially climbing steep hills." She also complains of malaise. On physical examination, a heliotrope rash is observed around her eyes, and multiple hyperkeratotic, flat, red papules with central atrophy are present on the back of the metacarpophalangeal and interphalangeal joints. Deposits of calcium are also noted on the pads of her fingers. Her serum creatine kinase levels are elevated. Which of the following antibodies is most likely to be found in this patient?
Gastroenterology US Medical PG Practice Questions and MCQs
Question 61: A 47-year-old woman presents with weakness, shortness of breath, and lightheadedness. She says her symptoms onset gradually 4 months ago and have progressively worsened. Past medical history is significant for a long history of menorrhagia secondary to uterine fibroids. Her vital signs include: temperature 36.9°C (98.4°F), blood pressure 135/82 mm Hg, and pulse 97/min. Physical examination is unremarkable. Laboratory test results are shown below:
Hemoglobin 9.2 g/dL
Mean corpuscular volume (MCV) 74 μm3
Mean corpuscular hemoglobin (MCH) 21 pg/cell
Reticulocyte count 0.4 %
Serum ferritin 10 ng/mL
Which of the following is a specific feature of this patient's condition?
A. Leg ulcers
B. Jaundice
C. Restless leg syndrome (Correct Answer)
D. Loss of proprioception
E. Bone deformities
Explanation: ***Restless leg syndrome***
- This patient has **iron deficiency anemia** due to chronic blood loss from menorrhagia, evidenced by **low hemoglobin**, **microcytic (low MCV, MCH)**, and **low serum ferritin**. **Restless leg syndrome (RLS)** is a common neurological complication of iron deficiency anemia, even in cases of mild iron deficiency without overt anemia.
- The exact mechanism is unclear but may involve **iron's role in dopamine synthesis** and function in the brain, with dopamine dysregulation being implicated in RLS symptoms.
*Leg ulcers*
- **Leg ulcers** are more commonly associated with **sickle cell anemia** or other hemolytic anemias, due to vaso-occlusion and tissue hypoxia, and are not a characteristic feature of iron deficiency anemia.
- They can also occur in severe venous insufficiency or peripheral artery disease, which are not suggested by the patient's presentation.
*Jaundice*
- **Jaundice** indicates **hemolysis** or liver dysfunction, neither of which is consistent with iron deficiency anemia.
- Iron deficiency anemia is typically **hypoproliferative**, meaning the bone marrow is not producing enough red blood cells, rather than premature destruction.
*Loss of proprioception*
- **Loss of proprioception** (along with vibratory sensation) is a hallmark of **vitamin B12 deficiency (pernicious anemia)** due to demyelination of posterior columns of the spinal cord.
- This patient presents with microcytic, hypochromic anemia and low ferritin, indicative of iron deficiency, not macrocytic anemia or B12 deficiency.
*Bone deformities*
- **Bone deformities** are characteristic of chronic, severe anemias where the bone marrow expands to compensate for erythropoiesis, such as **thalassemia major** or severe **sickle cell disease**.
- These are not typically seen in iron deficiency anemia, which rarely causes such extreme bone marrow expansion.
Question 62: A 32-year-old male patient presents to a medical office requesting screening for colorectal cancer. He currently has no symptoms and his main concern is that his father was diagnosed with colorectal cancer at 55 years of age. What screening strategy would be the most appropriate?
A. Perform a colonoscopy at the age of 40 and repeat every 3 years
B. Perform a colonoscopy at the age of 50 and repeat every 5 years
C. Perform a colonoscopy at the age of 40 and repeat every 5 years (Correct Answer)
D. Perform a colonoscopy at the age of 50 and repeat every 10 years
E. Perform a colonoscopy now and repeat every 10 years
Explanation: ***Perform a colonoscopy at the age of 40 and repeat every 5 years***
- For individuals with a **first-degree relative** diagnosed with colorectal cancer before age 60, screening should begin **10 years earlier than the youngest diagnosis in the family, OR at age 40, whichever comes first**.
- In this case, 10 years before the father's diagnosis (age 55) would be age 45, but many guidelines recommend starting at **age 40 as a standard minimum** for those with first-degree relative history, making this the most appropriate choice.
- Due to the increased risk, the recommended interval for repeat colonoscopy in this high-risk group is typically **every 5 years**, assuming no significant polyps are found.
*Perform a colonoscopy at the age of 40 and repeat every 3 years*
- While starting at age 40 is appropriate given the family history, repeating every 3 years for a patient with no current symptoms and a single affected first-degree relative is generally **more frequent** than standard guidelines recommend.
- A 3-year interval is usually reserved for individuals with **multiple adenomas** found on previous colonoscopy or more significant risk factors such as hereditary cancer syndromes.
*Perform a colonoscopy at the age of 50 and repeat every 5 years*
- Starting at age 50 is the recommendation for individuals with **average risk** for colorectal cancer, which does not apply to this patient due to his father's early diagnosis (before age 60).
- The 5-year repeat interval is sometimes used in high-risk groups, but the **initial screening age** is incorrect for this patient with increased familial risk.
*Perform a colonoscopy at the age of 50 and repeat every 10 years*
- Starting at age 50 and repeating every 10 years is the standard guideline for **average-risk** individuals who have a normal colonoscopy.
- This option does not account for the patient's **increased risk** due to family history, making both the starting age and interval inappropriate.
*Perform a colonoscopy now and repeat every 10 years*
- Performing a colonoscopy at age 32 is generally **too early** given that guidelines recommend starting 10 years earlier than the youngest affected relative or at age 40, whichever comes first.
- A 10-year repeat interval is only appropriate for **average-risk** individuals with a normal initial colonoscopy, not for those with significant family history.
Question 63: A 55-year-old female presents to clinic with recurrent episodes of abdominal discomfort and pain for the past month. She reports that the pain occurs 2-3 hours after meals, usually at midnight, and rates it as moderate to severe in intensity when it occurs. She also complains of being fatigued all the time. Past medical history is insignificant. She is an office secretary and says that the job has been very stressful recently. Her temperature is 98.6°F (37.0°C), respiratory rate is 15/min, pulse is 67/min, and blood pressure is 122/98 mm Hg. Her BMI is 34. A physical examination reveals conjunctival pallor and mild tenderness over her epigastric region. Blood tests show:
Hb%: 10 gm/dL
Total count (WBC): 11,000 /mm3
Differential count:
Neutrophils: 70%
Lymphocytes: 25%
Monocytes: 5%
ESR: 10 mm/hr
Which of the following is the most likely diagnosis?
A. Pancreatitis
B. Acute cholecystitis
C. Duodenal peptic ulcer (Correct Answer)
D. Gallbladder cancer
E. Choledocholithiasis
Explanation: ***Duodenal peptic ulcer***
- The patient's symptoms, including **abdominal pain 2-3 hours after meals** and **midnight pain**, are classic for a duodenal ulcer. This pain pattern is due to the buffering effect of food wearing off, allowing acid to irritate the ulcer.
- The presence of **conjunctival pallor** and **anemia (Hb% 10 gm/dL)** suggests **chronic blood loss**, which is a common complication of peptic ulcers.
*Pancreatitis*
- Pancreatitis typically presents with **severe, epigastric pain radiating to the back**, often exacerbated by fatty meals.
- Lab findings would usually show **elevated amylase and lipase**, which are not mentioned here.
*Acute cholecystitis*
- Characterized by **right upper quadrant pain** that is often constant and severe, sometimes radiating to the right shoulder or back.
- This condition is usually associated with **fever**, **leukocytosis**, and **Murphy's sign**, which are absent in this presentation.
*Gallbladder cancer*
- While it can cause abdominal pain and weight loss, the classic cyclical pain pattern linked to meals is not characteristic.
- It often presents with **jaundice** in advanced stages, which is not noted in this patient.
*Choledocholithiasis*
- Typically presents with **biliary colic**, which is episodic, severe right upper quadrant or epigastric pain, often radiating to the back.
- It can lead to **obstructive jaundice** and **cholangitis**, symptoms not reported by the patient.
Question 64: A 72-year-old man presents to his primary care physician with the symptom of generalized malaise over the last month. He also has abdominal pain that has been persistent and not relieved by ibuprofen. He has unintentionally lost 22 pounds recently. During this time, the patient has experienced intermittent diarrhea when he eats large meals. The patient has a past medical history of alcohol use, obesity, diabetes mellitus, hypertension, IV drug use, and asthma. His current medications include disulfiram, metformin, insulin, atorvastatin, lisinopril, albuterol, and an inhaled corticosteroid. The patient attends weekly Alcoholics Anonymous meetings and was recently given his two week chip for not drinking. His temperature is 99.5°F (37.5°C), blood pressure is 100/57 mmHg, pulse is 88/min, respirations are 11/min, and oxygen saturation is 98% on room air. The patient's abdomen is tender to palpation, and the liver edge is palpable 2 cm inferior to the rib cage. Neurologic exam demonstrates gait that is not steady. Which of the following is the best initial diagnostic test for this patient?
A. Sudan black stain of the stool
B. Ultrasound of the abdomen
C. CT scan of the abdomen (Correct Answer)
D. Liver function tests including bilirubin levels
E. Stool guaiac test and culture
Explanation: ***CT scan of the abdomen***
- This patient presents with **generalized malaise, persistent abdominal pain, significant unintentional weight loss**, and **intermittent diarrhea**, pointing towards a serious underlying condition such as **pancreatic cancer**.
- A **CT scan of the abdomen** is the best initial diagnostic test for evaluating the pancreas and surrounding structures for masses, inflammation, or other abnormalities given these alarming symptoms.
*Sudan black stain of the stool*
- A Sudan black stain is used to detect **fat malabsorption (steatorrhea)**, which might explain the diarrhea.
- While steatorrhea can be present, it does not address the primary concern of **weight loss** and **persistent abdominal pain**, which could indicate a mass or malignancy.
*Ultrasound of the abdomen*
- An ultrasound can be useful for evaluating the liver and gallbladder, especially if **biliary obstruction** is suspected.
- However, ultrasound is often limited in its ability to visualize the entire pancreas due to overlying bowel gas and its retroperitoneal location, making it less sensitive for pancreatic masses compared to CT.
*Liver function tests including bilirubin levels*
- Liver function tests (LFTs) and bilirubin levels help assess liver health and detect **biliary obstruction**, which could be a complication of pancreatic disease.
- While important for comprehensive evaluation, LFTs alone do not directly identify the underlying cause of the abdominal pain and weight loss, and they are not the best initial test to look for a mass.
*Stool guaiac test and culture*
- A stool guaiac test detects **occult blood in the stool**, indicating gastrointestinal bleeding, while a stool culture identifies infectious causes of diarrhea.
- Although diarrhea is present, the predominant symptoms of **unexplained weight loss** and **persistent abdominal pain** make a bleeding or infectious cause less likely to be the primary diagnosis; these tests would not identify a solid mass.
Question 65: A 44-year-old woman comes to the emergency department because of a 10-hour history of severe nausea and abdominal pain that began 30 minutes after eating dinner. The pain primarily is in her right upper quadrant and occasionally radiates to her back. She has a history of type 2 diabetes mellitus and hypercholesterolemia. Current medications include metformin and atorvastatin. She is 163 cm (5 ft 4 in) tall and weighs 91 kg (200 lb); BMI is 34 kg/m2. Her temperature is 38.8°C (101.8°F), pulse is 100/min, respirations are 14/min, and blood pressure is 150/76 mm Hg. Abdominal examination shows right upper quadrant tenderness with guarding. A bedside ultrasound shows a gall bladder wall measuring 6 mm, pericholecystic fluid, sloughing of the intraluminal membrane, and a 2 x 2-cm stone at the neck of the gallbladder. The common bile duct appears unremarkable. Laboratory studies show leukocytosis and normal liver function tests. Intravenous fluids are started, and she is given ketorolac for pain control. Which of the following is the most appropriate next step in management?
A. Endoscopic retrograde cholangiopancreatography
B. CT scan of the abdomen with contrast
C. Elective laparoscopic cholecystectomy in 6 weeks
D. Emergent open cholecystectomy (Correct Answer)
E. Antibiotic therapy
Explanation: ***Emergent open cholecystectomy***
- This patient presents with **severe acute cholecystitis** with signs of gangrenous changes: fever (38.8°C), leukocytosis, gallbladder wall thickening (6 mm), pericholecystic fluid, and **sloughing of intraluminal membrane** (indicating necrosis).
- The stone obstructing the gallbladder neck and signs of gangrenous cholecystitis require **urgent surgical intervention** to prevent perforation, empyema, or sepsis.
- Her comorbidities (diabetes, obesity) further increase the risk of complications from delayed surgery.
- **Note on surgical approach:** In current practice, laparoscopic cholecystectomy is typically attempted first even in severe cases, with conversion to open if necessary. Among the given options, this is the only choice representing urgent surgical management, which is the critical decision point. The emphasis here is on **emergent timing** rather than elective delay.
*Endoscopic retrograde cholangiopancreatography*
- ERCP is indicated for **choledocholithiasis** (common bile duct stones causing obstruction, jaundice, or cholangitis).
- This patient has **normal liver function tests** and an **unremarkable common bile duct** on ultrasound, making ERCP unnecessary.
*CT scan of the abdomen with contrast*
- The bedside ultrasound has already established the diagnosis of severe acute cholecystitis with adequate detail for surgical planning.
- CT scan would **delay definitive treatment** without providing additional actionable information in this clear-cut case.
*Elective laparoscopic cholecystectomy in 6 weeks*
- Delayed elective surgery is appropriate for **uncomplicated symptomatic cholelithiasis** or after conservative management of mild cholecystitis.
- This patient has **severe/gangrenous cholecystitis** with high risk of perforation or sepsis, requiring immediate intervention, not delayed surgery.
*Antibiotic therapy*
- Antibiotics are an important **adjunct** in managing acute cholecystitis to prevent septic complications and should be initiated.
- However, antibiotics alone are **not definitive treatment** for obstructive cholecystitis; the inflamed gallbladder must be removed surgically.
Question 66: A 45-year-old man presents to the office for evaluation of pruritic skin lesions, which he has had for 1 month on his elbows and knees. He has been using over-the-counter ointments, but they have not helped. He has not seen a healthcare provider for many years. He has no known allergies. His blood pressure is 140/80 mm Hg, his pulse is 82 beats per minute, his respirations are 18 breaths per minute, and his temperature is 37.2°C (98.9°F). On examination, clustered vesicular lesions are noted on both elbows and knees. Cardiovascular and pulmonary exams are unremarkable. Which of the following would most likely be associated with this patient’s condition?
A. Acanthosis nigricans
B. Malabsorption (Correct Answer)
C. Transmural inflammation of the colon
D. Double bubble on X-ray
E. Erythema nodosum
Explanation: ***Malabsorption***
- The patient's presentation of **pruritic, clustered vesicular lesions** on the elbows and knees is highly characteristic of **dermatitis herpetiformis**.
- Dermatitis herpetiformis is strongly associated with **celiac disease**, an autoimmune condition leading to **malabsorption** due to gluten-induced damage to the small intestinal villi.
*Acanthosis nigricans*
- This condition presents as **dark, velvety patches of skin**, typically in body folds like the neck and armpits, and is not characterized by vesicular lesions.
- It is frequently associated with **insulin resistance**, obesity, and certain malignancies (e.g., gastric adenocarcinoma), not primarily with gluten sensitivity.
*Transmural inflammation of the colon*
- **Transmural inflammation of the colon** is a hallmark of **Crohn's disease**, a type of inflammatory bowel disease.
- While celiac disease and other autoimmune conditions can coexist, the skin lesions described (dermatitis herpetiformis) are not a primary manifestation of Crohn's disease.
*Double bubble on X-ray*
- The **"double bubble" sign on X-ray** is indicative of **duodenal obstruction**, typically seen in conditions like duodenal atresia or annular pancreas in neonates.
- This finding is unrelated to the skin condition and its associated systemic disease presented in the adult patient.
*Erythema nodosum*
- **Erythema nodosum** presents as **tender, red nodules** typically on the shins, reflecting inflammation of subcutaneous fat.
- It is often a reaction to various systemic illnesses (e.g., infections, inflammatory bowel disease, sarcoidosis) but is not associated with vesicular skin lesions or celiac disease.
Question 67: A 59-year-old man presents to the emergency department with a 6 day history of persistent fevers. In addition, he has noticed that he feels weak and sometimes short of breath. His past medical history is significant for congenital heart disease though he doesn't remember the specific details. He has been unemployed for the last 3 years and has been occasionally homeless. Physical exam reveals nailbed splinter hemorrhages and painful nodes on his fingers and toes. Blood cultures taken 12 hours apart grow out Streptococcus gallolyticus. Which of the following is most likely associated with this patient's disease?
A. Intravenous drug abuse
B. Left-sided colon cancer (Correct Answer)
C. Genitourinary procedures
D. Dental procedures due to poor hygiene
E. Prosthetic heart valves
Explanation: ***Left-sided colon cancer***
- The isolation of **Streptococcus gallolyticus** (formerly *S. bovis*) in blood cultures is strongly associated with **colorectal malignancy**, particularly left-sided colon cancer.
- This association is so significant that it warrants a **colonoscopy** in affected patients, even in the absence of typical GI symptoms.
*Intravenous drug abuse*
- While intravenous drug abuse is a risk factor for infective endocarditis, it is typically associated with **tricuspid valve involvement** and virulent organisms like **Staphylococcus aureus**.
- The patient's symptoms and *S. gallolyticus* infection are not classic for IV drug use-related endocarditis.
*Genitourinary procedures*
- Genitourinary procedures can lead to bacteremia and endocarditis, often involving organisms like **Enterococcus faecalis**.
- There is no indication of recent genitourinary procedures or *Enterococcus* infection in this patient.
*Dental procedures due to poor hygiene*
- Poor dental hygiene and dental procedures are risk factors for endocarditis involving **viridans group streptococci** (e.g., *S. sanguinis, S. mitis*).
- The identified organism, *Streptococcus gallolyticus*, is not typically linked to oral flora or dental procedures.
*Prosthetic heart valves*
- Prosthetic heart valves are a significant risk factor for infective endocarditis, which can be caused by a variety of organisms including **Staphylococcus species**, **coagulase-negative staphylococci**, and **streptococci**.
- While the patient has underlying congenital heart disease, the specific pathogen *S. gallolyticus* points predominantly towards an underlying **gastrointestinal pathology**.
Question 68: A 23-year-old woman comes to the physician because of a 2-month history of diarrhea, flatulence, and fatigue. She reports having 3–5 episodes of loose stools daily that have an oily appearance. The symptoms are worse after eating. She also complains of an itchy rash on her elbows and knees. A photograph of the rash is shown. Further evaluation of this patient is most likely to show which of the following findings?
A. Elevated exhaled hydrogen concentration
B. Microcytic, hypochromic red blood cells
C. Elevated urine tryptophan levels
D. PAS-positive intestinal macrophages
E. HLA-DQ2 serotype (Correct Answer)
Explanation: ***HLA-DQ2 serotype***
- The patient's symptoms of **diarrhea, flatulence, fatigue, and oily stools** (steatorrhea) are highly suggestive of **malabsorption**. The itchy rash on the elbows and knees, known as **dermatitis herpetiformis**, is pathognomonic for **celiac disease**.
- **Celiac disease** is strongly associated with the **HLA-DQ2** (and less commonly HLA-DQ8) serotypes. Testing for these HLA alleles can help confirm genetic susceptibility to the condition.
*Elevated exhaled hydrogen concentration*
- An **elevated exhaled hydrogen concentration** is indicative of **small intestinal bacterial overgrowth (SIBO)** or **lactose intolerance**.
- While these can cause symptoms similar to malabsorption (diarrhea, flatulence), they do not typically present with **dermatitis herpetiformis**.
*Microcytic, hypochromic red blood cells*
- **Microcytic, hypochromic red blood cells** are characteristic of **iron deficiency anemia**, which commonly occurs in **celiac disease** due to malabsorption in the proximal small intestine (duodenum and jejunum).
- While iron deficiency can be seen in celiac disease, it is not specific to this condition and does not explain the pathognomonic **dermatitis herpetiformis** rash.
*Elevated urine tryptophan levels*
- **Elevated urine tryptophan levels** are associated with **Hartnup disease**, a rare inherited disorder affecting neutral amino acid transport.
- This finding is not directly related to the common manifestations of malabsorption or dermatitis herpetiformis seen in celiac disease.
*PAS-positive intestinal macrophages*
- **PAS-positive intestinal macrophages** are a characteristic histological finding in **Whipple's disease**, caused by the bacterium *Tropheryma whipplei*.
- While Whipple's disease can cause malabsorption, it is a much rarer condition and does not typically present with **dermatitis herpetiformis**.
Question 69: A 28-year-old male comes to the physician for worsening back pain. The pain began 10 months ago, is worse in the morning, and improves with activity. He has also had bilateral hip pain and difficulty bending forward during exercise for the past 3 months. He has celiac disease and eats a gluten-free diet. Examination shows a limited range of spinal flexion. Flexion, abduction, and external rotation of both hips produces pain. Further evaluation of this patient is most likely to show which of the following laboratory findings?
A. Presence of anti-Ro and anti-La antibodies
B. HLA-DR3-positive genotype
C. HLA-B27 positive genotype (Correct Answer)
D. Presence of anti-dsDNA antibodies
E. High levels of rheumatoid factor
Explanation: ***HLA-B27 positive genotype***
* The patient's symptoms of **inflammatory back pain** (worse in the morning, improves with activity, chronic) and **bilateral hip pain** are highly suggestive of a **spondyloarthropathy**, particularly **ankylosing spondylitis**.
* **HLA-B27** is strongly associated with ankylosing spondylitis and other spondyloarthropathies, making its presence a likely finding.
*Presence of anti-Ro and anti-La antibodies*
* These antibodies are primarily associated with **Sjögren's syndrome** but can also be seen in systemic lupus erythematosus (SLE) and neonatal lupus.
* The patient's clinical presentation does not align with Sjögren's syndrome, which typically involves sicca symptoms (dry eyes, dry mouth).
*HLA-DR3-positive genotype*
* **HLA-DR3** is associated with various autoimmune conditions, including specific types of **celiac disease**, **Type 1 diabetes**, and **systemic lupus erythematosus**.
* While the patient has celiac disease, his primary symptoms point towards a spondyloarthropathy, which is not directly linked to HLA-DR3.
*Presence of anti-dsDNA antibodies*
* **Anti-dsDNA antibodies** are highly specific for **systemic lupus erythematosus (SLE)**, particularly active lupus nephritis.
* The patient's presentation of inflammatory back pain and hip involvement is not typical for SLE, which would usually present with systemic symptoms like rash, serositis, or hematologic abnormalities.
*High levels of rheumatoid factor*
* **Rheumatoid factor (RF)** is primarily associated with **rheumatoid arthritis (RA)**, which typically presents with symmetric, inflammatory arthritis of small joints, often in the hands and feet.
* RA usually spares the axial spine (except for the cervical spine), and the patient's symptoms of significant back and hip pain are not characteristic of RA.
Question 70: A 13-year-old girl is admitted to the hospital due to muscle weakness, pain, and arthralgia in her wrist joints. The patient says, "I am having trouble walking home after school, especially climbing steep hills." She also complains of malaise. On physical examination, a heliotrope rash is observed around her eyes, and multiple hyperkeratotic, flat, red papules with central atrophy are present on the back of the metacarpophalangeal and interphalangeal joints. Deposits of calcium are also noted on the pads of her fingers. Her serum creatine kinase levels are elevated. Which of the following antibodies is most likely to be found in this patient?
A. Anti-centromere
B. Anti-histone
C. Anti-Jo-1 (Correct Answer)
D. Anti-Scl-70
E. Anti-Sm
Explanation: ***Anti-Jo-1***
- This patient presents with classic signs and symptoms of **juvenile dermatomyositis**, including **proximal muscle weakness**, **arthralgia**, elevated **creatine kinase**, **heliotrope rash** (periorbital violaceous rash), **Gottron's papules** (hyperkeratotic papules over MCP/IP joints), and **calcinosis**.
- Among the given options, **anti-Jo-1** is the most appropriate antibody, though it should be noted that anti-Jo-1 antibodies are **relatively uncommon in juvenile dermatomyositis** (found in <5% of pediatric cases) compared to adult dermatomyositis/polymyositis (20-30% of cases).
- **Anti-Jo-1** (anti-histidyl-tRNA synthetase) is an **anti-synthetase antibody** associated with myositis, particularly when accompanied by **interstitial lung disease, Raynaud's phenomenon, arthritis, and "mechanic's hands"** (anti-synthetase syndrome).
- The most common antibodies in **juvenile dermatomyositis** are actually **anti-Mi-2, anti-TIF1-gamma (p155/140), and anti-NXP2**, which are more specific for the pediatric form and associated with calcinosis.
*Anti-centromere*
- **Anti-centromere antibodies** are characteristic of **limited cutaneous systemic sclerosis (CREST syndrome)**, which includes **C**alcinosis, **R**aynaud's phenomenon, **E**sophageal dysmotility, **S**clerodactyly, and **T**elangiectasias.
- While calcinosis is present in this patient, the other key features of CREST syndrome (sclerodactyly, telangiectasias, esophageal symptoms) are absent, and the **heliotrope rash and Gottron's papules are pathognomonic for dermatomyositis**, not scleroderma.
*Anti-histone*
- **Anti-histone antibodies** are primarily associated with **drug-induced lupus erythematosus** (DILE), commonly caused by medications like procainamide, hydralazine, isoniazid, or quinidine.
- This patient's presentation with **proximal muscle weakness, markedly elevated creatine kinase, heliotrope rash, and Gottron's papules** is characteristic of inflammatory myopathy, not drug-induced lupus.
*Anti-Scl-70*
- **Anti-Scl-70 antibodies** (anti-topoisomerase I) are highly specific for **diffuse cutaneous systemic sclerosis**, which presents with widespread skin thickening, Raynaud's phenomenon, and internal organ involvement.
- While systemic sclerosis can involve muscle weakness, the **heliotrope rash and Gottron's papules are pathognomonic for dermatomyositis**, not scleroderma, making this diagnosis unlikely.
*Anti-Sm*
- **Anti-Sm antibodies** (anti-Smith) are highly specific for **systemic lupus erythematosus (SLE)** and are one of the diagnostic criteria.
- While SLE can cause myalgia, arthralgia, and various rashes, the **markedly elevated creatine kinase** (indicating true myositis), along with the **pathognomonic heliotrope rash and Gottron's papules**, clearly point to dermatomyositis rather than SLE.
