Gastroenterology — MCQs

Gastroenterology Indian Medical PG Practice Questions and MCQs

Question 491: Which of the following is NOT included in the armamentarium of tests for malabsorption syndrome?

A. D-Xylose absorption test
B. 14C-triolein breath test
C. 13C-trioctanoin breath test
D. 13C-triclosan breath test (Correct Answer)

Explanation: ### Explanation The diagnosis of malabsorption syndrome involves identifying the specific nutrient being poorly absorbed (carbohydrates, fats, or proteins). [1] **Why Option D is Correct:** The **$^{13}$C-triclosan breath test** does not exist as a diagnostic tool for malabsorption. **Triclosan** is an antibacterial and antifungal agent commonly found in consumer products like toothpaste and soaps; it is not a substrate used to measure metabolic or absorptive functions of the gastrointestinal tract. **Analysis of Incorrect Options:** * **A. D-Xylose absorption test:** This is a classic test used to differentiate **mucosal causes** of malabsorption (e.g., Celiac disease) from **pancreatic insufficiency**. Since D-xylose is a pentose sugar that does not require pancreatic enzymes for absorption, low urinary excretion indicates proximal small intestinal mucosal disease. [1] * **B. $^{14}$C-triolein breath test:** This is a gold-standard screening test for **fat malabsorption**. Triolein is a triglyceride; if lipase activity and mucosal absorption are intact, it is metabolized, and labeled $CO_2$ is exhaled. [1] * **C. $^{13}$C-trioctanoin breath test:** This test utilizes medium-chain triglycerides (MCTs) to evaluate **pancreatic exocrine function** and lipid digestion. $^{13}$C is a non-radioactive isotope, making it safer than $^{14}$C for clinical use. [1] **Clinical Pearls for NEET-PG:** * **Best Initial Test for Steatorrhea:** Sudan III staining (qualitative). * **Gold Standard for Fat Malabsorption:** 72-hour fecal fat estimation (Quantitative; >7g/day is abnormal). * **Schilling Test:** Historically used for Vitamin B12 malabsorption (now largely replaced by anti-IF antibodies and MMA levels). * **Hydrogen Breath Test:** Used for diagnosing Carbohydrate malabsorption (Lactose intolerance) and Small Intestinal Bacterial Overgrowth (SIBO). [2]

Question 492: What is the treatment of choice for chronic ulcerative colitis?

A. 5-aminosalicylic acid (Correct Answer)
B. Azathioprine
C. Metronidazole
D. Salicylates

Explanation: **Explanation:** The mainstay of treatment for **Ulcerative Colitis (UC)** depends on the severity and extent of the disease [1]. For the induction and maintenance of remission in mild-to-moderate chronic UC, **5-Aminosalicylic acid (5-ASA)** compounds, such as Sulfasalazine or Mesalamine, are the **treatment of choice** [1]. * **Mechanism:** 5-ASA works topically on the colonic mucosa to inhibit cytokine production (IL-1, TNF-α) and modulate the inflammatory response. * **Why 5-ASA is correct:** It is the first-line agent for both inducing remission and preventing relapses in chronic stable disease [1]. **Analysis of Incorrect Options:** * **B. Azathioprine:** This is a thiopurine immunosuppressant used for **steroid-dependent** or refractory UC [1]. It is not the first-line choice for general chronic management due to its slow onset of action (3–6 months) and side-effect profile. * **C. Metronidazole:** While useful in Crohn’s disease (especially perianal disease) or Pouchitis, antibiotics have **no proven role** in the primary treatment of chronic UC. * **D. Salicylates:** This is a broad term that includes Aspirin. While 5-ASA is a salicylate derivative, "Salicylates" as a general category is imprecise. In medical exams, **5-ASA** is the specific pharmacological term required. **High-Yield Clinical Pearls for NEET-PG:** * **Sulfasalazine** consists of 5-ASA linked to sulfapyridine. The sulfapyridine moiety causes most side effects (e.g., hypersensitivity, oligospermia). * **Mesalamine** is the preferred 5-ASA as it lacks the sulfa component, leading to better tolerance. * **Distal Disease:** For proctitis or ulcerative proctosigmoiditis, **topical (rectal) 5-ASA** is more effective than oral therapy [1]. * **Surgery:** Total Proctocolectomy with Ileal Pouch-Anal Anastomosis (IPAA) is the **curative** procedure for UC [2].

Question 493: Chylous ascites is caused by all of the following except?

A. Colloid carcinoma of stomach (Correct Answer)
B. Tuberculosis
C. Trauma
D. Nephrotic syndrome

Explanation: Chylous ascites is the accumulation of lipid-rich lymph (chyle) in the peritoneal cavity, characterized by a milky appearance and triglyceride levels typically >200 mg/dL. It results from the disruption of the lymphatic system due to obstruction or trauma. [1] **Why Colloid Carcinoma of the Stomach is the correct answer:** While malignancies are the leading cause of chylous ascites in adults (especially lymphomas), **Colloid (Mucinous) carcinoma of the stomach** typically causes **pseudomyxoma peritonei** or mucinous ascites rather than chylous ascites. In these cases, the fluid is gelatinous and contains mucin-secreting cells, not milky chyle. **Analysis of other options:** * **Tuberculosis:** This is the most common infectious cause of chylous ascites in developing countries. It causes obstruction of the lacteals and lymph nodes by granulomatous infiltration or direct rupture of lymphatics. * **Trauma:** Both surgical trauma (e.g., abdominal aortic aneurysm repair, retroperitoneal lymph node dissection) and blunt abdominal trauma can cause direct leakage of chyle into the peritoneum. * **Nephrotic Syndrome:** Though rare, it can cause chylous ascites due to increased lymphatic flow and bowel wall edema, leading to leakage, or associated hypoalbuminemia causing lymphatic dysfunction. **NEET-PG High-Yield Pearls:** * **Most common cause (Adults):** Lymphoma (Western world); Tuberculosis (Developing countries). * **Most common cause (Children):** Congenital lymphatic malformations. [1] * **Diagnostic Marker:** Triglyceride level >200 mg/dL (milky appearance is suggestive but not pathognomonic). * **Management:** High-protein, low-fat diet with **Medium Chain Triglycerides (MCTs)**, as MCTs are absorbed directly into the portal vein, bypassing the lymphatic system.

Question 494: What is the most common presenting symptom of Zollinger-Ellison syndrome?

A. Diarrhea
B. Abdominal pain (Correct Answer)
C. Esophageal symptoms
D. Flushing

Explanation: Zollinger-Ellison Syndrome (ZES) is caused by a gastrin-secreting neuroendocrine tumor (gastrinoma), leading to massive gastric acid hypersecretion [1]. **Why Abdominal Pain is Correct:** The hallmark of ZES is the development of severe, often refractory, peptic ulcer disease (PUD). **Abdominal pain**, resulting from these peptic ulcers, is the most common presenting symptom, occurring in **75% to 90%** of patients [1]. While these ulcers typically occur in the first part of the duodenum, their presence in atypical locations (e.g., distal duodenum or jejunum) is highly suggestive of ZES. **Analysis of Incorrect Options:** * **A. Diarrhea:** This is the second most common symptom (occurring in ~50% of cases). It is caused by the high acid volume damaging the intestinal mucosa and inactivating pancreatic enzymes (leading to steatorrhea). In 7-10% of patients, diarrhea may be the *only* symptom, but it is not the most common overall. * **C. Esophageal symptoms:** While gastroesophageal reflux disease (GERD) symptoms like heartburn are common due to hyperacidity, they are less frequent than primary ulcer-related abdominal pain. * **D. Flushing:** This is a characteristic feature of **Carcinoid Syndrome**, not ZES [1]. Gastrinomas do not typically produce the vasoactive substances (like serotonin) required to cause flushing. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most gastrinomas are found in the **"Gastrinoma Triangle"** (bounded by the cystic duct/common bile duct junction, the junction of the 2nd and 3rd parts of the duodenum, and the neck/body of the pancreas). * **Association:** Approximately 25% of ZES cases are associated with **Multiple Endocrine Neoplasia type 1 (MEN1)**. * **Diagnosis:** The best initial screening test is a **fasting serum gastrin level** (>1000 pg/mL is diagnostic). The confirmatory test is the **Secretin Stimulation Test** (gastrin levels rise >200 pg/mL after secretin injection).

Question 495: Which of the following is not a malabsorption syndrome?

A. Whipple's disease
B. Coeliac disease
C. Tropical sprue
D. Tangier's disease (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Tangier’s disease**. **Why Tangier’s disease is the correct answer:** Tangier’s disease is an autosomal recessive **lipid metabolism disorder**, not a malabsorption syndrome. It is caused by a mutation in the **ABCA1 gene**, which leads to a deficiency in High-Density Lipoprotein (HDL). This results in the accumulation of cholesterol esters in reticuloendothelial tissues. Clinical hallmarks include **orange-colored tonsils**, hepatosplenomegaly, and peripheral neuropathy. It does not involve the malabsorption of nutrients in the small intestine. **Why the other options are incorrect:** * **Whipple’s Disease:** A systemic infectious malabsorption syndrome caused by *Tropheryma whipplei* [1]. It typically presents with diarrhea, weight loss, arthralgia, and lymphadenopathy [1], [2]. * **Coeliac Disease:** An immune-mediated enteropathy triggered by gluten ingestion in genetically susceptible individuals (HLA-DQ2/DQ8) [3], [4]. It causes villous atrophy leading to global malabsorption [2]. * **Tropical Sprue:** A chronic diarrheal illness seen in tropical regions, characterized by malabsorption of nutrients (especially Vitamin B12 and Folate) due to structural damage to the small intestinal mucosa [2]. **NEET-PG High-Yield Pearls:** * **Tangier’s Disease Key Sign:** Enlarged, orange-colored tonsils (pathognomonic). * **Whipple’s Disease Diagnosis:** PAS-positive macrophages in the lamina propria of the small intestine [1]. * **Coeliac Disease Screening:** Anti-tissue transglutaminase (anti-tTG) IgA is the best initial test. * **D-Xylose Test:** Used to differentiate mucosal malabsorption (e.g., Celiac) from pancreatic insufficiency. In mucosal disease, D-xylose levels in urine/blood will be low.

Question 496: Which of the following is true about Crohn's disease?

A. Continuous involvement
B. Sinus tracts and fistulas (Correct Answer)
C. Mesenteric lymphadenitis
D. Strawberry ulcers

Explanation: **Explanation:** **Crohn’s Disease (CD)** is a chronic inflammatory bowel disease characterized by **transmural inflammation**, meaning it affects all layers of the bowel wall (mucosa to serosa) [1]. 1. **Why Option B is Correct:** Because the inflammation is transmural, it leads to deep linear ulcerations that can penetrate through the bowel wall. This process results in the formation of **sinus tracts** (blind-ended tracks) and **fistulas** (communications between two epithelial-lined surfaces, e.g., entero-enteric, entero-vesical, or perianal fistulas) [1]. This is a hallmark feature that distinguishes CD from Ulcerative Colitis (UC). 2. **Why Other Options are Incorrect:** * **Option A:** CD is characterized by **"skip lesions"** (discontinuous involvement). Continuous involvement from the rectum upwards is a classic feature of **Ulcerative Colitis** [1]. * **Option C:** While lymphadenopathy can occur, **Mesenteric lymphadenitis** is specifically the primary clinical mimic of acute appendicitis or Yersinia enterocolitica infection, rather than a defining diagnostic feature of CD. * **Option D:** **"Strawberry mucosa"** is a classic endoscopic description for **Cholesterolosis** of the gallbladder. CD is instead associated with **"Cobblestone appearance"** due to intersecting longitudinal and transverse ulcers. **High-Yield NEET-PG Pearls:** * **Pathology:** Non-caseating granulomas (pathognomonic but only seen in ~50%), creeping fat, and string sign of Kantor (on barium swallow) [1]. * **Site:** Most common site is the **terminal ileum** [1]. * **Serology:** ASCA (Anti-Saccharomyces cerevisiae antibodies) is positive in CD, whereas p-ANCA is positive in UC. * **Smoking:** Smoking is a risk factor for CD but is protective in UC.

Question 497: Zollinger-Ellison syndrome is characterized by all of the following except?

A. Post bulbar ulcer
B. Recurrent duodenal ulcer
C. Severe diarrhea
D. Massive HCl secretion in response to histamine injection (Correct Answer)

Explanation: **Explanation:** Zollinger-Ellison Syndrome (ZES) is caused by a gastrin-secreting tumor (gastrinoma), leading to hypergastrinemia and autonomous, maximal stimulation of gastric parietal cells [1]. **Why Option D is the Correct Answer (The "Except"):** In ZES, the parietal cells are already being stimulated to their **maximal capacity** by the extremely high levels of endogenous gastrin. Therefore, the administration of exogenous stimulants like histamine or pentagastrin fails to produce a significant further increase in acid output. The **Basal Acid Output (BAO)** is already very high (often >15 mEq/hr), making the BAO to MAO (Maximal Acid Output) ratio >0.6. **Analysis of Incorrect Options:** * **A & B (Post-bulbar and Recurrent Ulcers):** While 75% of ZES ulcers occur in the first part of the duodenum, ulcers in the **post-bulbar region** (distal duodenum or jejunum) are highly suggestive of ZES. These ulcers are often refractory to standard therapy and recur frequently. * **C (Severe Diarrhea):** Diarrhea occurs in ~50% of patients. It is caused by the massive volume of acid entering the small intestine, which inactivates pancreatic enzymes (leading to steatorrhea) and damages the intestinal mucosa. **NEET-PG High-Yield Pearls:** * **Location:** Most gastrinomas are found in the **"Gastrinoma Triangle"** (confluence of cystic/common bile duct, junction of 2nd/3rd parts of duodenum, and neck/body of pancreas). * **Association:** 25% of cases are associated with **MEN-1 syndrome** (3Ps: Parathyroid, Pancreas, Pituitary). * **Best Screening Test:** Fasting Serum Gastrin (>1000 pg/mL is diagnostic). * **Confirmatory Test:** **Secretin Stimulation Test** (Secretin paradoxically increases gastrin levels in ZES, whereas it inhibits it in normal individuals).

Question 498: Which of the following is false regarding spontaneous bacterial peritonitis?

A. Commonly seen in cirrhosis of the liver
B. The most important diagnostic test is abdominal paracentesis
C. The most common manifestation is fever
D. The most common pathogen is anaerobic bacteria (Correct Answer)

Explanation: Explanation: Spontaneous Bacterial Peritonitis (SBP) is an acute bacterial infection of ascitic fluid without an identifiable intra-abdominal surgical source. **Why Option D is the correct (False) statement:** The most common pathogens in SBP are **aerobic Gram-negative bacilli**, specifically ***Escherichia coli*** (most common), followed by *Klebsiella pneumoniae*. Gram-positive cocci like *Streptococcus pneumoniae* are also seen [1]. **Anaerobic bacteria are rare** in SBP because the oxygen tension of ascitic fluid in cirrhosis is typically high enough to inhibit their growth. If anaerobes are isolated, one should suspect Secondary Peritonitis (e.g., gut perforation). **Analysis of other options:** * **Option A:** SBP is a classic complication of **cirrhosis** with ascites, occurring in up to 30% of patients. It results from bacterial translocation from the gut into the mesenteric lymph nodes and then the bloodstream. * **Option B:** **Abdominal paracentesis** is the gold standard diagnostic test. A diagnosis is confirmed when the ascitic fluid **Absolute Neutrophil Count (ANC) is ≥250 cells/mm³** [2]. * **Option C:** **Fever** is the most frequent clinical manifestation (present in ~80% of cases), followed by abdominal pain and altered mental status (hepatic encephalopathy). **High-Yield Clinical Pearls for NEET-PG:** * **Treatment of choice:** Third-generation cephalosporins (e.g., **Cefotaxime**). * **Albumin Therapy:** Administering IV albumin (1.5g/kg on day 1, 1g/kg on day 3) reduces the risk of hepatorenal syndrome and mortality. * **Prophylaxis:** Indicated for patients with low ascitic protein (<1.5 g/dL) or prior SBP episodes; **Norfloxacin** or Rifaximin are commonly used. * **Culture-Negative Neutrocytic Ascites (CNNA):** ANC ≥250 but culture is negative; it is treated identically to SBP.

Question 499: What is the earliest symptom of primary biliary cirrhosis?

A. Jaundice
B. Pruritus (Correct Answer)
C. Melanosis
D. Vomiting

Explanation: **Explanation:** Primary Biliary Cholangitis (formerly known as Primary Biliary Cirrhosis) is a chronic, autoimmune cholestatic liver disease characterized by the destruction of small intrahepatic bile ducts [1]. **Why Pruritus is the Correct Answer:** **Pruritus (itching)** is classically the **earliest and most common symptom**, often preceding the onset of jaundice by months or even years [1]. It is typically worse at night and is thought to be caused by the accumulation of endogenous opioids or bile salts that stimulate peripheral nerve endings. Fatigue is another very early symptom, but among the options provided, pruritus is the hallmark initial presentation [1]. **Analysis of Incorrect Options:** * **A. Jaundice:** This is a late-stage finding in PBC [1]. Its appearance usually signifies significant ductal destruction and indicates a poorer prognosis or progression toward liver failure. * **C. Melanosis:** Hyperpigmentation (melanosis) of exposed skin areas can occur due to increased melanin deposition, but it occurs much later in the disease course than pruritus [1]. * **D. Vomiting:** This is a non-specific gastrointestinal symptom and is not a characteristic or early feature of the cholestatic process in PBC. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Classically affects middle-aged women (9:1 female-to-male ratio) [2]. * **Serology:** **Anti-Mitochondrial Antibody (AMA)** is the highly specific hallmark (positive in >95% of cases) [2]. * **Biochemical Marker:** Characterized by a disproportionate rise in **Alkaline Phosphatase (ALP)**. * **Associated Conditions:** Frequently associated with other autoimmune diseases like Sjögren’s syndrome, CREST syndrome, and Thyroiditis [2]. * **Treatment:** **Ursodeoxycholic acid (UDCA)** is the first-line treatment to slow disease progression.

Question 500: Which of the following organs is NOT involved in Whipple's disease?

A. Heart
B. CNS
C. Lungs (Correct Answer)
D. GI tract

Explanation: Whipple’s disease is a rare, multisystemic infectious disease caused by the gram-positive bacterium **Tropheryma whipplei** [1]. It primarily affects middle-aged Caucasian males and is characterized by its ability to infiltrate various organ systems via infected macrophages [1]. 1. **Why Lungs is the correct answer:** While Whipple’s disease is a systemic condition, the **lungs are typically spared**. Although rare pleuropulmonary symptoms like pleuritis or chronic cough can occur, the lungs are not considered a classic or primary site of involvement compared to the heart, brain, and joints [1]. 2. **Why other options are incorrect:** * **GI Tract (Option D):** This is the most common site. It causes malabsorption, diarrhea, and weight loss [1]. Histology shows PAS-positive macrophages in the lamina propria with "foamy" appearance. * **CNS (Option B):** Involved in about 10–40% of cases [1]. It can present with dementia, ataxia, or the pathognomonic **oculomasticatory myorhythmia** (pendular eye movements with synchronous jaw contractions). * **Heart (Option A):** Cardiac involvement is common, most frequently presenting as **culture-negative endocarditis** or pericarditis [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Causative Agent:** *Tropheryma whipplei* [1]. * **Classic Triad:** Diarrhea/Malabsorption, Weight loss, and Migratory large-joint Arthralgia (often the earliest symptom) [1]. * **Diagnosis:** Small bowel biopsy showing **PAS-positive, Acid-fast negative** macrophages containing rod-shaped bacilli. * **Electron Microscopy:** Shows "trilaminar" cell wall. * **Treatment:** Initial IV Ceftriaxone for 2 weeks, followed by oral **Trimethoprim-Sulfamethoxazole (TMP-SMX)** for 1 year to prevent CNS relapse.

Practice by Chapter

Esophageal Disorders

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Peptic Ulcer Disease

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Inflammatory Bowel Disease

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Irritable Bowel Syndrome

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Malabsorption Syndromes

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Pancreatitis (Acute and Chronic)

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Gastrointestinal Bleeding

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Liver Diseases and Cirrhosis

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Viral Hepatitis

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Biliary Tract Disorders

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Gastrointestinal Motility Disorders

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Gastrointestinal Malignancies

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