A 53-year-old man presents to your office with a 2 month history of abdominal bloating. He states that he feels full after eating only a small amount and has experienced bloating, diarrhea, and occasionally vomiting when he tries to eat large amounts. He states his diarrhea has now become more profuse and is altering the quality of his life. One week ago, the patient was given antibiotics for an ear infection. He states he is trying to eat more healthy and has replaced full fat with fat free dairy and is reducing his consumption of meat. His temperature is 99.0°F (37.2°C), blood pressure is 164/99 mmHg, pulse is 85/min, respirations are 14/min, and oxygen saturation is 98% on room air. Laboratory values from a previous office visit are notable for a hemoglobin A1c of 13%. Which of the following is the best treatment of this patient's diarrhea?
Q32
A 14-year-old boy comes to the physician because of an itchy rash on his right arm for 1 day. The rash started as small papules, then progressed into blisters with oozing. He has had atopic dermatitis at the age of 6 years. His vital signs are within normal limits. A photograph of the patient's arm is shown. There is no lymphadenopathy. Avoidance of contact with which of the following would most likely have prevented this patient's symptoms?
Q33
A 51-year-old white female presents to her primary care physician for a regular check-up. She endorses eating a healthy diet with a balance of meat and vegetables. She also states that she has a glass of wine each night with dinner. As part of the evaluation, a complete blood count and blood smear were performed and are remarkable for: Hemoglobin 8.7 g/dL, Hematocrit 27%, MCV 111 fL, and a smear showing macrocytes and several hypersegmented neutrophils. Suspecting an autoimmune condition with anti-intrinsic factor antibodies, what other finding might you expect in this patient?
Q34
Treatment with intravenous acyclovir is initiated. Three days later, the patient develops progressively worse fatigue, headache, and colicky pain in his right flank. His temperature is 36.7°C (98°F), pulse is 85/min, and blood pressure is 135/80 mm Hg. Examination shows no new lesions. Laboratory studies show:
Hemoglobin 11.3 g/dL
Serum
Na+ 140 mEq/L
Cl- 99 mEq/L
K+ 5.5 mEq/L
HCO3- 22 mEq/L
Urea nitrogen 56 mg/dL
Creatinine 3.2 mg/dL
Which of the following is the most likely finding on urinalysis?
Q35
A 28-year-old man comes to the physician for the evaluation of five episodes of painful oral ulcers over the past year. During this period, he has also had two painful genital ulcers that healed without treatment. He reports frequently having diffuse joint pain, malaise, and low-grade fever. There is no personal or family history of serious illness. He emigrated to the US from Syria with his family four years ago. He is sexually active with one female partner and they do not use condoms. He takes no medications. His temperature is 38°C (100.4°F), pulse is 90/min, and blood pressure is 130/80 mm Hg. Physical examination shows three painful ulcers on the oral buccal mucosa. Pelvic examination shows that the external genitalia has several healing scars. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?
Q36
A 67-year-old man presents to his primary care physician for abdominal pain. The patient states that he has had abdominal pain for the past month that has been steadily worsening. In addition, he endorses weight loss and general fatigue. The patient has a past medical history of obesity, diabetes, and hypertension. His current medications include metformin, insulin, and lisinopril. The patient is a current smoker and drinks roughly 3 drinks per day. His temperature is 99.5°F (37.5°C), blood pressure is 139/79 mmHg, pulse is 95/min, respirations are 17/min, and oxygen saturation is 98% on room air. The patient's cardiac and pulmonary exams are within normal limits. Examination of the patient's lower extremity reveals multiple tender palpable masses bilaterally that track linearly along the patient's lower extremity. Which of the following is the next best step in management?
Q37
A 44-year-old man presents to a clinic for the evaluation of difficulty swallowing for the past few days. He says that he has noticed progressively worsening chest pain when he attempts to swallow solids or liquids. He works from a home office, has not had any recent sick contacts, and is currently not sexually active. His medical history includes AIDS. His current medications include emtricitabine, rilpivirine, and tenofovir. His temperature is 38.1°C (100.6°F), pulse is 72/min, respirations are 18/min, and blood pressure is 136/84 mm Hg. A physical examination is notable for a dry mouth with red mucosa and no distinct plaques or patches, and a supple neck with no masses or cervical lymphadenopathy. An esophagogastroduodenoscopy shows small white patches within the esophageal lumen. A biopsy of one of the lesions is performed and the microscopic appearance of the finding is shown below. Which of the following is the most likely diagnosis?
Q38
A 36-year-old Caucasian woman is referred to the outpatient clinic by a physician at a health camp for 6-months of foul-smelling diarrhea with bulky and floating stools as well as significant flatulence which makes her extremely uncomfortable at work and social events. She has concomitant weight loss and recently fractured her wrist in a seemingly insignificant fall from her own height. Vital signs are normal and a physical examination shows grouped, papulovesicular, pruritic skin lesions, as well as areas of hypoesthesia in the hands and feet. Which of the following would be most useful in this case?
Q39
A 73-year-old man presents to his primary care physician complaining of increased urinary frequency, nocturia, and incomplete emptying after void. He is otherwise healthy, with no active medical problems. On examination, a large, symmetric, firm, smooth prostate is palpated, but otherwise the exam is normal. Which of the following is a potential complication of the patient's present condition?
Q40
A 52-year-old woman with HIV infection is brought to the emergency department 20 minutes after she had a generalized tonic-clonic seizure. She appears lethargic and confused. Laboratory studies show a CD4+ count of 89 cells/μL (N > 500). A CT scan of the head with contrast shows multiple ring-enhancing lesions in the basal ganglia and subcortical white matter. An India ink preparation of cerebrospinal fluid is negative. Which of the following is the most likely diagnosis?
Gastroenterology US Medical PG Practice Questions and MCQs
Question 31: A 53-year-old man presents to your office with a 2 month history of abdominal bloating. He states that he feels full after eating only a small amount and has experienced bloating, diarrhea, and occasionally vomiting when he tries to eat large amounts. He states his diarrhea has now become more profuse and is altering the quality of his life. One week ago, the patient was given antibiotics for an ear infection. He states he is trying to eat more healthy and has replaced full fat with fat free dairy and is reducing his consumption of meat. His temperature is 99.0°F (37.2°C), blood pressure is 164/99 mmHg, pulse is 85/min, respirations are 14/min, and oxygen saturation is 98% on room air. Laboratory values from a previous office visit are notable for a hemoglobin A1c of 13%. Which of the following is the best treatment of this patient's diarrhea?
A. Metoclopramide
B. Vancomycin
C. Elimination of dairy from the diet
D. Better glycemic control
E. Rifaximin (Correct Answer)
Explanation: ***Rifaximin***
- The patient's history of bloating, early satiety, diarrhea, and vomiting, especially with a high HbA1c of 13%, suggests **diabetic gastroparesis** complicated by **small intestinal bacterial overgrowth (SIBO)**.
- Poorly controlled diabetes leads to gastroparesis, which causes stasis and creates an environment conducive to bacterial overgrowth. The recent antibiotic use may have further disrupted the gut microbiome, exacerbating SIBO.
- **Rifaximin** is a non-absorbable antibiotic that is first-line therapy for SIBO, reducing bacterial load in the small intestine and directly addressing the profuse diarrhea and bloating.
*Metoclopramide*
- This is a prokinetic agent that would primarily address **gastroparesis** by improving gastric emptying, but it would not directly treat the diarrhea associated with SIBO.
- While gastroparesis is likely contributing to the patient's symptoms, treating the bacterial overgrowth is the more direct approach for the chief complaint of profuse, life-altering diarrhea.
*Vancomycin*
- This antibiotic is typically used to treat **Clostridioides difficile infection (CDI)**, especially after recent antibiotic use.
- Although the patient recently took antibiotics, the clinical picture of chronic bloating, early satiety over 2 months, and the context of poorly controlled diabetes points more toward SIBO than acute CDI, which typically presents with more acute onset watery diarrhea.
*Elimination of dairy from the diet*
- Though the patient has switched to fat-free dairy, there is no direct evidence for **lactose intolerance** as the primary cause of his severe diarrhea and other symptoms.
- While lactose intolerance can cause bloating and diarrhea, it doesn't explain the full symptom complex, particularly early satiety and vomiting in the context of poorly controlled diabetes.
*Better glycemic control*
- **Improved glycemic control** is crucial for preventing and managing diabetic complications, including gastroparesis and SIBO in the long term.
- However, for acute symptom relief of severe, life-altering diarrhea, a more immediate intervention directed at the likely underlying cause (SIBO) is needed, rather than waiting for improved glycemic control to take effect over weeks to months.
Question 32: A 14-year-old boy comes to the physician because of an itchy rash on his right arm for 1 day. The rash started as small papules, then progressed into blisters with oozing. He has had atopic dermatitis at the age of 6 years. His vital signs are within normal limits. A photograph of the patient's arm is shown. There is no lymphadenopathy. Avoidance of contact with which of the following would most likely have prevented this patient's symptoms?
A. Plants (Correct Answer)
B. Bees
C. Sun
D. Antibiotics
E. Gluten
Explanation: ***Plants***
- The rash described (small papules progressing to **blisters with oozing**) and the image depicting **linear or streaky vesicles** are classic for **allergic contact dermatitis**, particularly due to **poison ivy, oak, or sumac**.
- These plants contain **urushiol oil**, which causes a delayed type IV hypersensitivity reaction, leading to an intensely itchy, vesicular rash.
*Bees*
- A bee sting typically causes an immediate, localized reaction with a **wheal and flare**, pain, and swelling at the site of the sting.
- It does not usually present as widespread papules and oozing blisters in a linear pattern as seen in the image.
*Sun*
- Sun exposure can cause **sunburn** (erythema, pain, blistering in severe cases) or **photosensitivity reactions**, which usually affect sun-exposed areas diffusely.
- The rash in the image is not typical for a sunburn and lacks the diffuse distribution of most photosensitivity reactions.
*Antibiotics*
- Dermatological reactions to antibiotics can range from **maculopapular rashes** to severe conditions like **Stevens-Johnson syndrome**.
- They typically do not present as an acute, localized, intensely pruritic, vesicular, and oozing rash in a linear pattern.
*Gluten*
- **Dermatitis herpetiformis**, associated with **celiac disease** (gluten sensitivity), presents with intensely itchy papules and vesicles, often symmetrically distributed on extensor surfaces.
- However, the rash in the image appears to be an acute, unilateral, linear eruption, which is not characteristic of dermatitis herpetiformis.
Question 33: A 51-year-old white female presents to her primary care physician for a regular check-up. She endorses eating a healthy diet with a balance of meat and vegetables. She also states that she has a glass of wine each night with dinner. As part of the evaluation, a complete blood count and blood smear were performed and are remarkable for: Hemoglobin 8.7 g/dL, Hematocrit 27%, MCV 111 fL, and a smear showing macrocytes and several hypersegmented neutrophils. Suspecting an autoimmune condition with anti-intrinsic factor antibodies, what other finding might you expect in this patient?
A. Cheilosis
B. Bleeding gums
C. Abdominal colic
D. High serum TSH (Correct Answer)
E. Psoriasis
Explanation: ***High serum TSH***
- **Pernicious anemia** (due to anti-intrinsic factor antibodies) is an **autoimmune condition** frequently associated with other autoimmune diseases, particularly **autoimmune thyroiditis**, which would present with elevated TSH.
- The combination of **macrocytic anemia** (MCV 111 fL) with **hypersegmented neutrophils** strongly suggests vitamin B12 deficiency, often caused by pernicious anemia.
*Cheilosis*
- **Cheilosis** is typically associated with **iron deficiency anemia** or **riboflavin deficiency**, not vitamin B12 deficiency or pernicious anemia.
- The patient's **macrocytic anemia** points away from iron deficiency.
*Bleeding gums*
- **Bleeding gums** can be a sign of **vitamin C deficiency** (scurvy) or a bleeding disorder, neither of which is indicated by the provided blood work or clinical picture.
- It is not a characteristic finding in pernicious anemia.
*Abdominal colic*
- **Abdominal colic** can be a symptom of **lead poisoning** or certain gastrointestinal issues, but it is not typically associated with pernicious anemia or vitamin B12 deficiency.
- While some GI symptoms can occur with B12 deficiency, severe colic is less common.
*Psoriasis*
- **Psoriasis** is an autoimmune skin condition that is not specifically linked to pernicious anemia, despite both being autoimmune.
- There is no direct causal or common strong associative relationship between the two conditions like there is with pernicious anemia and autoimmune thyroid disease.
Question 34: Treatment with intravenous acyclovir is initiated. Three days later, the patient develops progressively worse fatigue, headache, and colicky pain in his right flank. His temperature is 36.7°C (98°F), pulse is 85/min, and blood pressure is 135/80 mm Hg. Examination shows no new lesions. Laboratory studies show:
Hemoglobin 11.3 g/dL
Serum
Na+ 140 mEq/L
Cl- 99 mEq/L
K+ 5.5 mEq/L
HCO3- 22 mEq/L
Urea nitrogen 56 mg/dL
Creatinine 3.2 mg/dL
Which of the following is the most likely finding on urinalysis?
A. Eosinophils and red blood cells
B. Gram-negative rods and white blood cell casts
C. Crystals and white blood cells (Correct Answer)
D. Fatty casts and proteinuria
E. Red blood cell casts and acanthocytes
Explanation: ***Crystals and white blood cells***
- The patient's symptoms (flank pain, fatigue, headache) and lab findings (elevated urea nitrogen, creatinine, and hyperkalemia) three days after starting IV acyclovir are highly suggestive of **acute kidney injury (AKI)** due to **acyclovir-induced nephrotoxicity**.
- **Acyclovir crystal nephropathy** occurs when the drug precipitates in the renal tubules, forming **crystals** that obstruct flow and cause inflammation. The presence of **white blood cells** would indicate this inflammatory response.
*Eosinophils and red blood cells*
- **Eosinophils** in urine are characteristic of **acute interstitial nephritis (AIN)**, which is typically a hypersensitivity reaction to drugs, but less common with acyclovir than crystal nephropathy and often presents with a rash and fever.
- While **red blood cells** might be present in AKI, **eosinophils** are a less likely primary finding for acyclovir nephropathy.
*Gram-negative rods and white blood cell casts*
- **Gram-negative rods** and **white blood cell casts** indicate an acute **pyelonephritis** (kidney infection).
- The clinical picture (no fever, recent acyclovir use, flank pain) is more consistent with drug-induced AKI rather than an ascending urinary tract infection.
*Fatty casts and proteinuria*
- **Fatty casts** and significant **proteinuria** are hallmarks of **nephrotic syndrome** (e.g., focal segmental glomerulosclerosis, membranous nephropathy).
- This patient's presentation with acute kidney injury after acyclovir initiation does not align with the typical features of nephrotic syndrome.
*Red blood cell casts and acanthocytes*
- **Red blood cell casts** and **acanthocytes** (dysmorphic red blood cells) are characteristic findings in **glomerulonephritis**, indicating glomerular bleeding.
- The patient's symptoms and rapid onset of kidney injury after acyclovir are not typical of glomerulonephritis.
Question 35: A 28-year-old man comes to the physician for the evaluation of five episodes of painful oral ulcers over the past year. During this period, he has also had two painful genital ulcers that healed without treatment. He reports frequently having diffuse joint pain, malaise, and low-grade fever. There is no personal or family history of serious illness. He emigrated to the US from Syria with his family four years ago. He is sexually active with one female partner and they do not use condoms. He takes no medications. His temperature is 38°C (100.4°F), pulse is 90/min, and blood pressure is 130/80 mm Hg. Physical examination shows three painful ulcers on the oral buccal mucosa. Pelvic examination shows that the external genitalia has several healing scars. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?
A. Chancroid
B. Behcet disease (Correct Answer)
C. Herpes simplex virus infection
D. Ankylosing spondylitis
E. Systemic lupus erythematosus
Explanation: ***Behcet disease***
- The recurrent episodes of **oral and genital ulcers**, along with **arthralgias**, **malaise**, and **fever**, are characteristic features of **Behcet disease**.
- His **Middle Eastern origin (Syria)** is a known predisposing factor for this condition.
*Chancroid*
- **Chancroid** typically presents with a **single, painful genital ulcer** and often associated **inguinal lymphadenopathy**.
- It does not explain the recurrent oral ulcers, diffuse joint pain, malaise, or fever.
*Herpes simplex virus infection*
- **HSV infection** can cause recurrent oral and genital ulcers, but these are typically **vesicular lesions** that then ulcerate.
- While it could cause recurrent ulcers, it does not typically explain the prominent and recurrent **arthralgias, malaise, or fever** in this pattern.
*Ankylosing spondylitis*
- Primarily affects the **axial skeleton**, causing **inflammatory back pain** and stiffness, particularly in young men.
- It is not associated with recurrent oral or genital ulcers.
*Systemic lupus erythematosus*
- While it can present with **oral ulcers** and **arthralgias**, it typically involves multiple organ systems and is associated with a wide range of other symptoms.
- **Genital ulcers** are not a common or characteristic feature of **SLE** in the way they are in Behcet's disease.
Question 36: A 67-year-old man presents to his primary care physician for abdominal pain. The patient states that he has had abdominal pain for the past month that has been steadily worsening. In addition, he endorses weight loss and general fatigue. The patient has a past medical history of obesity, diabetes, and hypertension. His current medications include metformin, insulin, and lisinopril. The patient is a current smoker and drinks roughly 3 drinks per day. His temperature is 99.5°F (37.5°C), blood pressure is 139/79 mmHg, pulse is 95/min, respirations are 17/min, and oxygen saturation is 98% on room air. The patient's cardiac and pulmonary exams are within normal limits. Examination of the patient's lower extremity reveals multiple tender palpable masses bilaterally that track linearly along the patient's lower extremity. Which of the following is the next best step in management?
A. Colonoscopy
B. CT scan of the abdomen (Correct Answer)
C. Upper GI endoscopy
D. Lower extremity ultrasound
E. CT scan of the chest
Explanation: ***CT scan of the abdomen***
- The patient's **worsening abdominal pain**, **weight loss**, and **smoking history** are highly concerning for a gastrointestinal malignancy, making a CT scan the most appropriate initial diagnostic step to evaluate for a mass or other abdominal pathology.
- The presence of **tender palpable masses bilaterally in the lower extremities that track linearly** is suggestive of **superficial thrombophlebitis** (Trousseau sign), which is often a paraneoplastic manifestation of an **abdominal adenocarcinoma**, further increasing the suspicion for an abdominal malignancy that can be visualized on CT.
*Colonoscopy*
- While **colonoscopy** is essential for diagnosing colorectal cancer, the abdominal pain, weight loss, and especially the **Trousseau sign** suggest a broader abdominal malignancy, which a CT scan can detect more comprehensively before a targeted endoscopic procedure.
- A CT scan can help identify the **location and extent** of any potential tumor, guiding subsequent investigations like colonoscopy if a colonic mass is suspected.
*Upper GI endoscopy*
- **Upper GI endoscopy** is indicated for symptoms localized to the upper gastrointestinal tract, such as dysphagia, acid reflux unresponsive to treatment, or upper GI bleeding.
- The patient's symptoms are vague abdominal pain and weight loss, and the **Trousseau sign** points towards a general abdominal malignancy rather than one specifically in the upper GI tract.
*Lower extremity ultrasound*
- A **lower extremity ultrasound** would be indicated if deep vein thrombosis (DVT) or other vascular abnormalities in the legs were the primary concern.
- Although the patient has palpable masses, the context of generalized abdominal symptoms and weight loss suggests these are more likely a **paraneoplastic phenomenon** (Trousseau sign) related to an underlying malignancy rather than isolated vascular clots.
*CT scan of the chest*
- A **CT scan of the chest** is primarily used to evaluate pulmonary or mediastinal pathology.
- While lung cancer can cause weight loss and fatigue, the primary symptom is **abdominal pain**, and the **Trousseau sign** directs attention toward an abdominal malignancy, making an abdominal CT the initial priority.
Question 37: A 44-year-old man presents to a clinic for the evaluation of difficulty swallowing for the past few days. He says that he has noticed progressively worsening chest pain when he attempts to swallow solids or liquids. He works from a home office, has not had any recent sick contacts, and is currently not sexually active. His medical history includes AIDS. His current medications include emtricitabine, rilpivirine, and tenofovir. His temperature is 38.1°C (100.6°F), pulse is 72/min, respirations are 18/min, and blood pressure is 136/84 mm Hg. A physical examination is notable for a dry mouth with red mucosa and no distinct plaques or patches, and a supple neck with no masses or cervical lymphadenopathy. An esophagogastroduodenoscopy shows small white patches within the esophageal lumen. A biopsy of one of the lesions is performed and the microscopic appearance of the finding is shown below. Which of the following is the most likely diagnosis?
A. Medication-induced esophagitis
B. Cytomegalovirus esophagitis
C. Eosinophilic esophagitis
D. Esophageal candidiasis (Correct Answer)
E. Herpes esophagitis
Explanation: ### ***Esophageal candidiasis***
- **Esophageal candidiasis** is strongly suggested by the patient's **AIDS diagnosis**, **dysphagia**, **odynophagia**, and endoscopic findings of **small white patches** in the esophagus. The microscopic image would likely show yeast, pseudohyphae, and budding cells.
- This infection is a common **opportunistic infection** in immunocompromised individuals, particularly those with HIV/AIDS, when CD4 counts are low.
### *Medication-induced esophagitis*
- **Medication-induced esophagitis** typically presents with **linear ulcers** or erosions, often at points of narrowing, and can be caused by drugs like tetracyclines, bisphosphonates, or NSAIDs.
- The **white patches** seen on endoscopy and the patient's HIV status make Candida infection a more likely cause than medication side effects.
### *Cytomegalovirus esophagitis*
- **Cytomegalovirus (CMV) esophagitis** is characterized by **large, shallow, linear ulcers** on endoscopy and would show **intranuclear and intracytoplasmic inclusions** on biopsy.
- While CMV esophagitis can occur in AIDS patients, the endoscopic appearance of **white patches** points away from CMV.
### *Eosinophilic esophagitis*
- **Eosinophilic esophagitis** is often associated with **atopic conditions** and manifests with **dysphagia**, **food impaction**, and endoscopic findings such as **trachealization** (rings) or **exudates**.
- The biopsy would show a high density of **eosinophils**, which is not consistent with the reported microscopic findings for this patient.
### *Herpes esophagitis*
- **Herpes esophagitis** typically presents with **multiple, small, deep ulcers** with a characteristic "volcano-like" appearance on endoscopy.
- Biopsy would reveal **multinucleated giant cells** and **Cowdry type A intranuclear inclusions**, findings inconsistent with the description of **white patches**.
Question 38: A 36-year-old Caucasian woman is referred to the outpatient clinic by a physician at a health camp for 6-months of foul-smelling diarrhea with bulky and floating stools as well as significant flatulence which makes her extremely uncomfortable at work and social events. She has concomitant weight loss and recently fractured her wrist in a seemingly insignificant fall from her own height. Vital signs are normal and a physical examination shows grouped, papulovesicular, pruritic skin lesions, as well as areas of hypoesthesia in the hands and feet. Which of the following would be most useful in this case?
A. Hydrogen breath test
B. D-xylose test
C. Urine levels 5-hydroxyindoleacetic acid
D. Anti-Saccharomyces cerevisiae antibodies (ASCAs)
E. Anti-tissue transglutaminase antibodies (Correct Answer)
Explanation: ***Anti-tissue transglutaminase antibodies***
- The patient presents with **foul-smelling, bulky, floating stools** (steatorrhea), **weight loss**, and **osteoporosis** (wrist fracture from minimal trauma), suggesting malabsorption.
- The presence of **dermatitis herpetiformis** (**grouped, papulovesicular, pruritic skin lesions**) and **neuropathy** (**hypoesthesia in hands and feet**) in a patient with malabsorption is highly suggestive of **celiac disease**, which is confirmed by anti-transglutaminase antibodies.
*Hydrogen breath test*
- This test is primarily used to diagnose **lactose intolerance** or **small intestinal bacterial overgrowth (SIBO)**.
- While SIBO can cause malabsorption, the constellation of symptoms including dermatitis herpetiformis and neuropathy strongly points away from SIBO as the primary diagnosis.
*D-xylose test*
- The D-xylose test assesses the **absorptive function of the small intestine**. A low urinary excretion of D-xylose indicates impaired absorption, suggesting mucosal damage.
- While it aids in diagnosing malabsorption, it is not specific for celiac disease and does not provide an etiological diagnosis. It would not be the "most useful" initial diagnostic step given the highly suggestive specific symptoms.
*Urine levels 5-hydroxyindoleacetic acid*
- **Elevated urine 5-HIAA** is a diagnostic marker for **carcinoid tumors**, which can cause diarrhea.
- However, the patient's presentation with malabsorption, dermatitis herpetiformis, and neuropathy is not consistent with carcinoid syndrome.
*Anti-Saccharomyces cerevisiae antibodies (ASCAs)*
- ASCAs are serological markers primarily used in the diagnosis and differentiation of **inflammatory bowel disease (IBD)**, particularly Crohn's disease.
- The patient's symptoms are more indicative of malabsorption syndrome rather than IBD.
Question 39: A 73-year-old man presents to his primary care physician complaining of increased urinary frequency, nocturia, and incomplete emptying after void. He is otherwise healthy, with no active medical problems. On examination, a large, symmetric, firm, smooth prostate is palpated, but otherwise the exam is normal. Which of the following is a potential complication of the patient's present condition?
A. Hydronephrosis (Correct Answer)
B. Renal cancer
C. Prostatitis
D. Prostate cancer
E. Bladder cancer
Explanation: ***Hydronephrosis***
- The symptoms of **urinary frequency, nocturia, and incomplete emptying** coupled with a **large, symmetric, firm, smooth prostate** are classic for **Benign Prostatic Hyperplasia (BPH)**.
- As BPH obstructs the urethra, the bladder works harder, and over time, the increased pressure can lead to **urine reflux** into the ureters and kidneys, causing **hydronephrosis** (swelling of the kidneys due to urine buildup) and potentially **renal damage**.
*Renal cancer*
- **Renal cancer** is not a direct complication of BPH; its development is typically insidious and not causally linked to bladder outlet obstruction.
- Risk factors for renal cancer include smoking, obesity, and hypertension, which are not mentioned here as present or directly related to BPH.
*Prostatitis*
- **Prostatitis** is an inflammation of the prostate gland, often presenting with pain, fever, and dysuria, which are not described in this patient's presentation.
- While BPH can increase the risk of urinary tract infections, it does not directly cause prostatitis.
*Prostate cancer*
- While both BPH and **prostate cancer** affect the prostate, they are distinct conditions; BPH does not *transform* into prostate cancer.
- **Prostate cancer** often presents with an **asymmetric, hard, nodular prostate** on examination, which is different from the described smooth, firm enlargement of BPH.
*Bladder cancer*
- **Bladder cancer** is not a direct complication of BPH, though chronic irritation from urinary stasis could theoretically increase risk, it's not a primary or direct complication.
- The most common symptom of bladder cancer is **painless hematuria**, which is not reported in this patient.
Question 40: A 52-year-old woman with HIV infection is brought to the emergency department 20 minutes after she had a generalized tonic-clonic seizure. She appears lethargic and confused. Laboratory studies show a CD4+ count of 89 cells/μL (N > 500). A CT scan of the head with contrast shows multiple ring-enhancing lesions in the basal ganglia and subcortical white matter. An India ink preparation of cerebrospinal fluid is negative. Which of the following is the most likely diagnosis?
A. Primary CNS lymphoma
B. HIV encephalopathy
C. Cryptococcal encephalitis
D. Cerebral toxoplasmosis (Correct Answer)
E. Progressive multifocal leukoencephalopathy
Explanation: ***Correct: Cerebral toxoplasmosis***
- The combination of **multiple ring-enhancing lesions** in the basal ganglia and subcortical white matter, severe **immunocompromise (CD4+ count <100 cells/μL)**, and neurological symptoms like seizures in an HIV-positive patient is highly suggestive of cerebral toxoplasmosis.
- Toxoplasmosis is the **most common cause of focal brain lesions** in HIV-infected patients, particularly when the CD4+ count is severely low.
*Incorrect: Primary CNS lymphoma*
- While primary CNS lymphoma also presents with **ring-enhancing lesions** and can occur in HIV-positive patients, it typically presents as a **single lesion or periventricular lesions**, rather than multiple basal ganglia lesions.
- It would be considered if toxoplasmosis treatment failed or if there was no response to antitoxoplasma therapy.
*Incorrect: HIV encephalopathy*
- This condition presents with **diffuse cerebral atrophy** and **white matter changes** on CT, not distinct ring-enhancing lesions.
- It is characterized by **cognitive decline** and motor dysfunction, typically without focal neurological deficits like seizures at onset.
*Incorrect: Cryptococcal encephalitis*
- Cryptococcal encephalitis usually presents with **meningeal symptoms** and **diffuse leptomeningeal enhancement** or hydrocephalus on imaging, rather than discrete ring-enhancing lesions in the basal ganglia.
- A **positive India ink stain** or cryptococcal antigen in CSF would be expected, which was negative in this case.
*Incorrect: Progressive multifocal leukoencephalopathy*
- This is caused by the **JC virus** and presents with **non-enhancing white matter lesions** that do not typically show mass effect or ring enhancement.
- It usually manifests as **subacute neurological deficits** such as hemiparesis or cognitive changes, rather than acute seizures from a mass lesion.