Gastroenterology Practice Questions

Q: Which substance is most often incriminated in the pathogenesis of hepatic encephalopathy?

Ammonia. **Explanation:** **Pathogenesis of Hepatic Encephalopathy (HE):** The correct answer is **Ammonia (NH₃)** [1]. In a healthy individual, ammonia is produced by the breakdown of proteins by intestinal bacteria and the metabolism of amino acids [2]. It is then transported via the portal vein to the liver, where it is converted into urea via the **Urea Cycle**. In patients with cirrhosis or portosystemic shunting, the liver fails to detoxify ammonia [1]. Elevated systemic ammonia crosses the **blood-brain barrier**, where it is taken up by **astrocytes**. Here, ammonia is converted into **glutamine** by the enzyme glutamine synthetase. The osmotic effect of excess glutamine leads to astrocyte swelling and cerebral edema, which are central to the pathogenesis of HE [2]. **Analysis of Incorrect Options:** * **A. Urea:** Urea is the non-toxic end product of ammonia metabolism [2]. While urea levels may be low in end-stage liver disease, it does not cause neurotoxicity. * **C. Uric Acid:** This is the end product of purine metabolism. Elevated levels cause gout or urate nephropathy, not encephalopathy. * **D. Creatinine:** This is a marker of renal function (muscle metabolism byproduct). While it rises in Hepatorenal Syndrome [3], it is not the causative agent of HE. **NEET-PG High-Yield Pearls:** * **Astrocyte Swelling:** The hallmark pathological change in HE. * **Alzheimer Type II Astrocytes:** Characteristically seen on brain histopathology in chronic HE. * **Precipitating Factors:** GI bleed (increases protein load), infections (SBP), hypokalemia, and constipation. * **Treatment Gold Standard:** **Lactulose** (converts NH₃ to non-absorbable NH₄⁺) and **Rifaximin** (reduces ammonia-producing gut flora).

Q: Which of the following statements regarding capsule endoscopy is false?

It is suitable for patients with bowel strictures.. The correct answer is **D**. Capsule endoscopy is **contraindicated** in patients with known or suspected bowel strictures, obstructions, or extensive Crohn’s disease with narrowing. This is because the non-dissolvable capsule (roughly the size of a large vitamin pill) can become trapped at the site of the stricture, leading to **capsule retention**, which may necessitate surgical or endoscopic retrieval. **Analysis of Options:** * **A & B:** These are true. Capsule endoscopy is non-invasive. The patient swallows the device with water; it requires **no sedation** and is **painless**, as it moves naturally through the GI tract via peristalsis [1]. * **C:** This is true. One of the primary clinical advantages of capsule endoscopy is its ability to visualize the **entire small bowel** (duodenum, jejunum, and ileum), areas that are often beyond the reach of conventional upper GI endoscopy and colonoscopy [1]. **Clinical Pearls for NEET-PG:** * **Primary Indication:** Obscure Gastrointestinal Bleeding (OGIB) is the most common indication. * **Gold Standard:** It is the gold standard for diagnosing mucosal lesions in the small intestine (e.g., Angiodysplasia, early Crohn’s). * **Patency Capsule:** If a stricture is suspected, a "Patency Capsule" (a dissolvable dummy capsule) is administered first. If it passes intact, the procedure is safe. * **Contraindications:** Besides strictures, other contraindications include pregnancy and implanted electromedical devices like pacemakers (though the latter is now considered a relative contraindication).

Q: Which one of the following is least expected to precipitate hepatic encephalopathy in a liver cirrhosis patient?

Peritoneal tap. Explanation: Hepatic Encephalopathy (HE) is a reversible neuropsychiatric syndrome caused by the accumulation of neurotoxins (primarily ammonia) due to portosystemic shunting and liver failure [1]. Why Peritoneal Tap is the correct answer: A diagnostic peritoneal tap (paracentesis) is a safe procedure used to rule out Spontaneous Bacterial Peritonitis (SBP). It does not precipitate HE. In fact, a large-volume therapeutic paracentesis is also safe, provided it is accompanied by albumin infusion to prevent post-paracentesis circulatory dysfunction. Unlike the other options, it does not increase ammonia production or cross the blood-brain barrier. Analysis of Incorrect Options: * Antibiotics (Option B): While antibiotics like Rifaximin are used to treat HE, certain nephrotoxic antibiotics (e.g., Aminoglycosides) can cause acute kidney injury (AKI). Renal failure reduces ammonia clearance, thereby precipitating HE. * Variceal Bleed (Option C): This is a classic precipitant. Blood in the GI tract is a massive protein load. Bacteria break down this hemoglobin into ammonia, which is then absorbed into the systemic circulation [1]. * Hypokalemia (Option D): Low potassium levels induce intracellular acidosis. To compensate, the kidneys increase ammonia production (ammoniagenesis) and exchange H+ for K+, leading to increased systemic ammonia levels. High-Yield Clinical Pearls for NEET-PG: * Most common precipitant of HE: Infections (SBP, UTI, Pneumonia) and Dehydration/Diuretics. * Metabolic triggers: Hypokalemia, Hyponatremia, and Metabolic Alkalosis (alkalosis favors the conversion of NH4+ to NH3, which crosses the blood-brain barrier more easily). * Drug triggers: Benzodiazepines, Narcotics, and Diuretics. * First-line treatment: Lactulose (converts NH3 to non-absorbable NH4+) and Rifaximin (reduces ammonia-producing gut flora).

Q: All of the following are features of Wilson's disease, except?

Testicular atrophy. **Explanation:** Wilson’s disease (Hepatolenticular degeneration) is an autosomal recessive disorder caused by a mutation in the **ATP7B gene** on chromosome 13. This leads to impaired biliary copper excretion and toxic accumulation in various organs, primarily the liver and brain [1]. **Why Testicular Atrophy is the Correct Answer:** Testicular atrophy is **not** a characteristic feature of Wilson’s disease. While Wilson’s can cause endocrine issues like delayed puberty or secondary amenorrhea due to chronic liver disease, direct gonadal involvement is rare. In contrast, testicular atrophy is a classic hallmark of **Hemochromatosis** (iron overload), which is a common distractor in NEET-PG questions. **Analysis of Other Options:** * **Hemolytic Anemia:** Wilson’s can present with Coombs-negative hemolytic anemia [1]. This occurs when sudden releases of copper from necrotic hepatocytes cause oxidative damage to red blood cell membranes. * **Chorea:** Copper deposition in the basal ganglia (specifically the putamen) leads to extrapyramidal symptoms [1]. While "wing-beating" tremors are classic, chorea, athetosis, and parkinsonism are frequently observed [1]. * **Chronic Active Hepatitis:** Liver involvement is the most common initial presentation in children. It can range from asymptomatic transaminitis to chronic active hepatitis, cirrhosis, or fulminant hepatic failure [1]. **NEET-PG High-Yield Pearls:** * **Diagnosis:** Low serum Ceruloplasmin ( 100 μg), and the presence of **Kayser-Fleischer (KF) rings** (copper in Descemet’s membrane). * **Ocular Sign:** "Sunflower cataract" is also seen. * **Treatment:** Drug of choice is **Penicillamine** (chelator). Trientine is an alternative. Oral Zinc is used for maintenance or in asymptomatic patients to prevent copper absorption.

Q: A 32-year-old man presents with abdominal pain. On examination, he is noted to have pigmented spots in the buccal region. He is diagnosed to have Peutz-Jeghers syndrome. What is a characteristic finding associated with this condition?

Hamartomatous polyps in the small intestine. **Explanation:** **Peutz-Jeghers Syndrome (PJS)** is an autosomal dominant condition characterized by the mutation of the **STK11 (LKB1)** gene on chromosome 19. The clinical hallmark of this syndrome is the presence of multiple **hamartomatous polyps** throughout the gastrointestinal tract, most commonly found in the **small intestine** (jejunum > ileum > duodenum), followed by the colon and stomach [1]. These polyps are histologically distinct, showing a "Christmas tree" branching pattern of smooth muscle. The patient in the question also exhibits the second classic feature: **mucocutaneous hyperpigmentation** (melanotic macules) on the lips, buccal mucosa, and digits. **Analysis of Options:** * **Option D (Correct):** Hamartomatous polyps in the small intestine are the defining gastrointestinal feature. They often lead to complications like intussusception (lead point) or occult GI bleeding. * **Option A & C (Incorrect):** Optic neuroma and cerebellar dysfunction (specifically Lhermitte-Duclos disease) are associated with **Cowden Syndrome**, another PTEN-related hamartoma tumor syndrome, not PJS. * **Option B (Incorrect):** Constricted pupils (miosis) are not a feature of PJS. This may be seen in Horner’s syndrome or opioid overdose, which have no association with this polyposis syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Cancer Risk:** PJS carries a significantly increased risk of both GI and extra-GI malignancies (Pancreas, Breast, Ovary, Lung, and Sertoli cell tumors of the testis) [1]. * **Screening:** Regular surveillance with upper GI endoscopy, colonoscopy, and capsule endoscopy/MR enterography is mandatory. * **Classic Triad:** 1. STK11 mutation, 2. Mucocutaneous pigmentation, 3. Hamartomatous polyps.

Question 1

Which substance is most often incriminated in the pathogenesis of hepatic encephalopathy?

Accepted Answer

Ammonia

Answer

Urea

Answer

Uric acid

Answer

Creatinine

Question 2

Which of the following statements regarding capsule endoscopy is false?

Accepted Answer

It is suitable for patients with bowel strictures.

Answer

Sedation is not required.

Answer

It is a painless procedure.

Answer

It can visualize the entire small bowel.

Question 3

Which one of the following is least expected to precipitate hepatic encephalopathy in a liver cirrhosis patient?

Accepted Answer

Peritoneal tap

Answer

Antibodies treatment

Answer

Variceal bleed

Answer

Hypokalemia

Question 4

A 51-year-old man presents with sudden onset of massive hematemesis of bright red blood. On physical examination, his temperature is 36.9°C, pulse is 103/min, respirations are 23/min, and blood pressure is 85/50 mm Hg. His spleen tip is palpable. Laboratory studies show a hematocrit of 21%. The serologic test result for HBsAg is positive. He has had no prior episodes of hematemesis. What is the most likely cause of his hematemesis?

Accepted Answer

Esophageal varices

Answer

Barrett esophagus

Answer

Candida albicans infection

Answer

Reflux esophagitis

Question 5

What is the commonest cause of Budd-Chiari syndrome?

Accepted Answer

Paroxysmal nocturnal hemoglobinuria

Answer

Valve in the inferior vena cava

Answer

Hepatocellular carcinoma

Answer

Renal cell carcinoma

Question 6

A 50-year-old male presents with pain in the upper abdomen, pruritus, jaundice, and weight loss. He has an elevated ANA. What is the likely diagnosis?

Accepted Answer

Primary sclerosing cholangitis

Answer

Klatskin tumor

Answer

Secondary sclerosing cholangitis

Answer

Choledocholithiasis

Question 7

All of the following are true about spontaneous bacterial peritonitis EXCEPT:

Accepted Answer

High ascitic fluid protein increases the risk.

Answer

Escherichia coli is the commonest organism.

Answer

It is due to bacterial translocation from normal gut flora.

Answer

A neutrophil count >250/mL in an ascitic fluid sample is diagnostic.

Question 8

All of the following are features of Wilson's disease, except?

Accepted Answer

Testicular atrophy

Answer

Hemolytic anemia

Answer

Chorea

Answer

Chronic active hepatitis

Question 9

An 88-year-old woman with osteoarthritis has noticed mild epigastric discomfort for several weeks. Naproxen has helped her joint symptoms. She has emesis that resembles coffee grounds on three occasions. What is the most likely cause of gastrointestinal blood loss?

Accepted Answer

Gastric ulcer

Answer

Mallory-Weiss tear

Answer

Aortoenteric fistula

Answer

Esophageal varices

Question 10

A 32-year-old man presents with abdominal pain. On examination, he is noted to have pigmented spots in the buccal region. He is diagnosed to have Peutz-Jeghers syndrome. What is a characteristic finding associated with this condition?

Accepted Answer

Hamartomatous polyps in the small intestine

Answer

Optic neuroma

Answer

Constricted pupil

Answer

Cerebellar dysfunction

Gastroenterology — MCQs

Gastroenterology — MCQs

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