Gastroenterology Practice Questions

Q: Which is the test of choice for assessment of mucosal function of the GIT?

D-xylose test. **Explanation:** The **D-xylose test** is the gold standard for assessing the **functional integrity of the proximal small intestinal mucosa**. D-xylose is a pentose sugar that is absorbed via passive diffusion in the proximal small bowel without requiring pancreatic enzymes. If the intestinal mucosa is damaged (e.g., in Celiac disease or Tropical sprue), absorption decreases, leading to low levels in the blood and urine. It is primarily used to differentiate **malabsorption** (mucosal disease) from **maldigestion** (pancreatic insufficiency). **Analysis of Incorrect Options:** * **A. Biopsy:** While a biopsy is the "gold standard" for providing a **histological diagnosis** (e.g., identifying villous atrophy), it assesses structure rather than overall mucosal function [1]. * **B. Schilling test:** This test specifically assesses **Vitamin B12 absorption**. It helps localize the cause of B12 deficiency (e.g., Pernicious anemia, ileal disease, or bacterial overgrowth) rather than general mucosal function. * **C. Small bowel study:** Imaging (like Barium follow-through) evaluates the **anatomy and transit time** of the GIT but cannot quantify the absorptive capacity of the mucosa. **NEET-PG High-Yield Pearls:** * **Normal Values:** After a 25g oral dose, a 5-hour urinary excretion of **>4.5g** is considered normal. * **False Positives:** Low urinary D-xylose can occur in **renal failure**, ascites, or **Small Intestinal Bacterial Overgrowth (SIBO)** (bacteria metabolize the sugar before absorption). * **Clinical Use:** It is the best initial test to distinguish between chronic pancreatitis (normal D-xylose) and Celiac disease (abnormal D-xylose).

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.

Question 1

Which is the test of choice for assessment of mucosal function of the GIT?

Accepted Answer

D-xylose test

Answer

Biopsy

Answer

Schilling test

Answer

Small bowel study

Question 2

Which of the following is FALSE regarding Primary Sclerosing Cholangitis (PSC)?

Accepted Answer

PSC in Ulcerative Colitis (UC) is associated in 30% of cases.

Answer

There is a low incidence of cholangitis.

Answer

There is an increased incidence of colonic carcinoma in PSC patients with UC.

Answer

Despite the presence of diffuse disease, the hepatic duct bifurcation is the most severely structured segment.

Question 3

What is the first-line treatment for Wilson disease with neurologic or psychiatric manifestations?

Accepted Answer

Tetrathiomolybdate and Zinc

Answer

Trientine and Zinc

Answer

Zinc alone

Answer

d-Penicillamine alone

Question 4

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 5

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 6

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 7

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 8

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 9

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 10

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

Gastroenterology — MCQs

Gastroenterology — MCQs

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