Gastroenterology Practice Questions

Q: During a routine pre-employment physical examination, an apparently healthy 24-year-old man is found to have increased serum levels of unconjugated bilirubin. Conjugated bilirubin and transaminases are normal. Careful questioning reveals no evidence of recent illnesses. Which of the following is the most likely diagnosis?

Gilbert syndrome. ### Explanation **Gilbert Syndrome** is the most likely diagnosis in this scenario [1]. It is a common, benign autosomal recessive condition characterized by a **reduced activity of the enzyme bilirubin uridine diphosphate-glucuronosyltransferase (UGT1A1)** [1]. This leads to intermittent episodes of mild **unconjugated hyperbilirubinemia**, typically triggered by stress, fasting, illness, or strenuous exercise. **Why it is the correct answer:** The patient is an asymptomatic young adult with isolated unconjugated hyperbilirubinemia and normal liver enzymes (ALT/AST). This "incidental finding" during routine screening is the classic presentation of Gilbert syndrome. Bilirubin levels rarely exceed 4 mg/dL, and the liver architecture remains normal. **Analysis of Incorrect Options:** * **Crigler-Najjar Syndrome:** Type I involves a total absence of UGT1A1 activity, leading to severe, life-threatening jaundice in infancy [1]. Type II (Arias syndrome) involves a severe deficiency (<10% activity) but is still more symptomatic and presents with higher bilirubin levels than Gilbert syndrome. * **Dubin-Johnson Syndrome:** This is a defect in the MRP2 transporter, resulting in **conjugated** hyperbilirubinemia. A key feature is a "black liver" due to pigment deposition. * **Rotor Syndrome:** Similar to Dubin-Johnson, this presents with **conjugated** hyperbilirubinemia due to impaired hepatic storage/uptake of bilirubin, but without the black liver pigmentation. **NEET-PG High-Yield Pearls:** * **Enzyme involved:** UGT1A1 (reduced to ~30% of normal) [1]. * **Trigger factors:** Fasting (the "Fasting Test" was historically used for diagnosis), dehydration, menstruation, and surgery. * **Treatment:** No treatment is required; the prognosis is excellent [1]. * **Differential Diagnosis:** Always rule out hemolysis; however, in Gilbert syndrome, hemoglobin and reticulocyte counts are normal [2].

Q: A 32-year-old Caucasian woman with a 12 pack-year history of smoking presents with diarrhea and right lower quadrant colicky pain. Physical examination reveals tender, red nodules on her legs. Radiological examination shows a specific presentation. What is the most likely diagnosis?

Crohn's disease. ***Crohn's disease*** - **Right lower quadrant pain** and **diarrhea** in a young smoker strongly suggests **terminal ileum** involvement, which is characteristic of Crohn's disease. - The **tender red nodules** on legs represent **erythema nodosum**, a common extraintestinal manifestation of Crohn's disease, and **smoking** is a significant risk factor. *Ulcerative colitis* - Typically presents with **bloody diarrhea** and **left lower quadrant pain** due to **rectosigmoid** involvement, not right-sided symptoms. - **Smoking is protective** against ulcerative colitis, unlike in this patient who is a smoker. *Ulcerative tuberculosis* - Usually affects the **ileocecal region** but presents with **systemic symptoms** like **fever**, **night sweats**, and **weight loss**. - More common in **endemic areas** and **immunocompromised patients**, not typically associated with erythema nodosum. *Hirschsprung's disease* - A **congenital condition** presenting in **infancy** with **chronic constipation** and **abdominal distension**. - Caused by **absence of ganglion cells** in the colon, not associated with inflammatory symptoms or erythema nodosum.

Q: What is the most common cause of malignant portal vein thrombosis?

Hepatocellular carcinoma. **Explanation:** **Hepatocellular Carcinoma (HCC)** is the most common cause of malignant portal vein thrombosis (PVT). This occurs due to the unique biological propensity of HCC for **angioinvasion**. HCC cells frequently invade the small branches of the portal vein, eventually extending into the main portal vein trunk. On imaging (Triphasic CT/MRI), malignant thrombus is characterized by expansion of the vessel lumen and "neovascularity" (the **"Thread and Streaks" sign**), where the thrombus itself shows arterial phase enhancement, mimicking the primary tumor. **Analysis of Incorrect Options:** * **Renal Cell Carcinoma (RCC):** While RCC is notorious for venous invasion, it characteristically involves the **Renal Vein** and extends into the **Inferior Vena Cava (IVC)**, rather than the portal system. * **Carcinoma of the Prostate:** This typically spreads via the Batson venous plexus to the spine or via lymphatics; it does not have a primary association with portal vein invasion. * **Carcinoma of the Colon:** While colorectal cancer frequently metastasizes to the liver via the portal vein, it rarely causes a direct malignant thrombus within the vein itself. It is more commonly associated with *bland* (non-malignant) thrombosis due to hypercoagulability. **High-Yield Clinical Pearls for NEET-PG:** * **Imaging Gold Standard:** Contrast-enhanced CT/MRI. A malignant thrombus will show **enhancement** (matching the HCC), whereas a bland thrombus will not. * **Doppler Ultrasound:** Malignant thrombi often show **pulsatile flow** (arterialization) within the thrombus. * **Bland vs. Malignant:** Bland thrombus is common in cirrhosis/portal hypertension; malignant thrombus is a hallmark of advanced HCC and significantly worsens the prognosis (BCLC Stage C).

Q: The presence of anti-Saccharomyces cerevisiae antibody is a surrogate marker of which of the following conditions?

Crohn's disease. The presence of **Anti-Saccharomyces cerevisiae antibodies (ASCA)** is a highly specific serological marker for **Crohn’s Disease (CD)**. ASCA are directed against mannan, a component of the cell wall of the yeast *Saccharomyces cerevisiae*. In patients with Crohn’s disease, increased intestinal permeability and an aberrant immune response lead to the formation of these antibodies. * **Crohn’s Disease (Option B):** ASCA is positive in approximately 60-70% of CD cases [2]. When combined with p-ANCA (which is typically negative in CD), it has a high positive predictive value for the diagnosis. * **Ulcerative Colitis (Option C):** The characteristic marker for UC is **p-ANCA** (Perinuclear Anti-Neutrophil Cytoplasmic Antibodies), seen in 60-80% of patients. ASCA is usually negative in UC [1]. * **Celiac Disease (Option A):** This is an autoimmune response to gluten [3]. Key markers include **Anti-tissue Transglutaminase (tTG) IgA** (the screening test of choice) and **Anti-Endomysial antibodies (EMA)** [3]. * **Tropical Sprue (Option D):** This is a malabsorption syndrome caused by chronic small bowel infection; it does not have specific diagnostic autoantibodies and is diagnosed via clinical history and biopsy. **High-Yield Clinical Pearls for NEET-PG:** * **ASCA (+) / p-ANCA (-):** Highly suggestive of Crohn’s Disease. * **ASCA (-) / p-ANCA (+):** Highly suggestive of Ulcerative Colitis. * ASCA levels in Crohn’s disease are often associated with a more aggressive phenotype, including ileal involvement and fibrostenosing disease. * Remember the "Rule of C": **C**rohn's = AS**C**A; **U**lcerative Colitis = p-ANCA (often associated with **U**veitis/P-ANCA).

Question 1

Which of the following statements is FALSE about Blind loop syndrome?

Accepted Answer

Broad-spectrum antibiotics are sufficient treatment for anatomic stasis

Answer

Also called Bacterial overgrowth syndrome

Answer

Macrocytic anemia due to Cobalamin deficiency

Answer

Malabsorption of fat-soluble vitamins

Question 2

A 56-year-old woman with a history of chronic viral hepatitis B and cirrhosis presents with light-headedness upon standing and dark black stools for 3 days. On examination, her blood pressure is 90/60 mm Hg supine and 76/60 mm Hg standing. Abdominal examination reveals distension with ascites, and multiple bruises are noted on her legs. Her laboratory findings include hemoglobin 9.0 g/dL, platelets 90,000/mL, albumin 3 g/dL, bilirubin 1.3 mg/dL, and an international normalized ratio (INR) of 2.5 (prothrombin time 25 seconds). Which of the following coagulation factors are most likely deficient in this patient?

Accepted Answer

II, V, VII, IX, X, and XI

Answer

V and VIII

Answer

VIII, IX, XI, and XII

Answer

XIII

Question 3

During a routine pre-employment physical examination, an apparently healthy 24-year-old man is found to have increased serum levels of unconjugated bilirubin. Conjugated bilirubin and transaminases are normal. Careful questioning reveals no evidence of recent illnesses. Which of the following is the most likely diagnosis?

Accepted Answer

Gilbert syndrome

Answer

Crigler-Najjar syndrome

Answer

Dubin-Johnson syndrome

Answer

Rotor syndrome

Question 4

A 50-year-old chronic alcoholic and smoker presents with intermittent episodes of epigastric pain, nausea, and vomiting, along with features of malabsorption for the past 6 months. The patient has lost 12 kg over the last year and was hospitalized for acute abdominal pain 3 years ago. Serum amylase and lipase levels are only mildly elevated. A CT scan of the abdomen and MRCP were performed. What is the most likely diagnosis?

Accepted Answer

Chronic pancreatitis

Answer

Acute pancreatitis

Answer

Pancreatic cancer

Answer

Pancreatic pseudocyst

Question 5

A 50-year-old man presented with one episode of hematemesis. On vital examination, HR was 110/min with BP of 110/80 mmHg. Systemic examination shows an enlarged spleen with dilated tortuous veins around the umbilicus. What is the first differential diagnosis?

Accepted Answer

Non-cirrhotic portal fibrosis

Answer

Kala Azar

Answer

Fatty liver

Answer

Non-alcoholic fatty liver disease

Question 6

Heyde's syndrome is characterized by which of the following triad?

Accepted Answer

Aortic stenosis, gastrointestinal bleeding, and angiodysplasia of the colon

Answer

Mitral stenosis, arthritis, and biliary cirrhosis

Answer

Mitral regurgitation, hiatus hernia, and cirrhosis

Answer

Pulmonary arterial hypertension, tricuspid regurgitation, and cirrhosis

Question 7

A 32-year-old Caucasian woman with a 12 pack-year history of smoking presents with diarrhea and right lower quadrant colicky pain. Physical examination reveals tender, red nodules on her legs. Radiological examination shows a specific presentation. What is the most likely diagnosis?

Accepted Answer

Crohn's disease

Answer

Ulcerative colitis

Answer

Ulcerative tuberculosis

Answer

Hirschsprung's disease

Question 8

A 30-year-old man presents with increasing difficulty swallowing both solids and liquids. Physical examination is noncontributory. Barium swallow study and esophageal manometry findings are as follows: Barium swallow shows abnormal esophageal motility. Esophageal manometry shows incomplete relaxation of the lower esophageal sphincter in response to swallowing, high resting lower esophageal pressure, and absent esophageal peristalsis. What is the most likely diagnosis?

Accepted Answer

Achalasia

Answer

Adenocarcinoma

Answer

Barrett esophagus

Answer

Squamous cell carcinoma

Question 9

What is the most common cause of malignant portal vein thrombosis?

Accepted Answer

Hepatocellular carcinoma

Answer

Renal cell carcinoma

Answer

Carcinoma of the prostate

Answer

Carcinoma of the colon

Question 10

The presence of anti-Saccharomyces cerevisiae antibody is a surrogate marker of which of the following conditions?

Accepted Answer

Crohn's disease

Answer

Celiac disease

Answer

Ulcerative colitis

Answer

Tropical sprue

Gastroenterology — MCQs

Gastroenterology — MCQs

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