Gastroenterology — MCQs

Gastroenterology Indian Medical PG Practice Questions and MCQs

Question 121: A 6-year-old boy presents with a palpable abdominal mass in the epigastrium. There is no bile in the vomitus. What is the clinical diagnosis?

A. Duodenal Atresia
B. Choledochal cyst
C. Pyloric stenosis (Correct Answer)
D. Oesophageal Atresia

Explanation: **Explanation:** The clinical presentation of a **palpable epigastric mass** combined with **non-bilious vomiting** is the classic hallmark of **Infantile Hypertrophic Pyloric Stenosis (IHPS)**. 1. **Why Pyloric Stenosis is correct:** In IHPS, hypertrophy of the pyloric sphincter muscle causes a functional gastric outlet obstruction. Because the obstruction is proximal to the Ampulla of Vater (where bile enters the duodenum), the vomitus is strictly **non-bilious**. The hypertrophied muscle is often palpable in the epigastrium or right upper quadrant as an **"olive-shaped mass."** While typically seen at 3–6 weeks of age, late presentations can occur. 2. **Why other options are incorrect:** * **Duodenal Atresia:** Characterized by **bilious vomiting** (as the block is usually distal to the bile duct) and the "double bubble" sign on X-ray. No palpable mass is typically present. * **Choledochal Cyst:** While it presents with a palpable mass in the right hypochondrium and jaundice (Todani’s triad), it does not typically cause gastric outlet obstruction or projectile vomiting. * **Oesophageal Atresia:** Presents immediately after birth with drooling, choking, and cyanosis during feeding. It does not present with an abdominal mass. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolic Abnormality:** Hypochloremic, hypokalemic, metabolic alkalosis with paradoxical aciduria. * **Investigation of Choice:** Ultrasonography (Criteria: Pyloric muscle thickness >4mm or length >14mm). * **Radiology Sign:** "String sign" or "Beak sign" on Barium swallow. * **Management:** Initial resuscitation with Normal Saline (0.9%) followed by **Ramstedt’s Pyloromyotomy**.

Question 122: What is the investigation of choice to diagnose Hirschsprung's disease?

A. Rectal manometry
B. Barium enema
C. Rectal biopsy (Correct Answer)
D. Laparotomy

Explanation: **Explanation:** Hirschsprung’s disease (Congenital Aganglionic Megacolon) is characterized by the absence of ganglion cells in the Meissner’s and Auerbach’s plexuses, typically starting from the internal anal sphincter and extending proximally. **Why Rectal Biopsy is the Correct Answer:** Full-thickness or suction **rectal biopsy** is the **Gold Standard** and investigation of choice. Diagnosis is confirmed by the histological demonstration of the **absence of ganglion cells** and the presence of hypertrophied nerve bundles. Additionally, Acetylcholinesterase (AChE) staining shows increased nerve fiber activity in the lamina propria/muscularis mucosa, which is highly diagnostic. **Analysis of Incorrect Options:** * **Rectal Manometry (Option A):** This is the most sensitive **screening test**. It shows the absence of the Recto-Anal Inhibitory Reflex (RAIR)—failure of the internal sphincter to relax upon rectal distension. It is useful in older children but can yield false results in neonates. * **Barium Enema (Option B):** This is the initial imaging modality. It classically shows a **"transition zone"** (dilated proximal colon and narrow distal aganglionic segment) and delayed evacuation of contrast. However, it is not definitive as the transition zone may not be apparent in the first few weeks of life. * **Laparotomy (Option C):** This is an invasive surgical procedure and is not used for primary diagnosis. It may be used intraoperatively to determine the level of aganglionosis via frozen section. **NEET-PG High-Yield Pearls:** * **Most common site:** Rectosigmoid (80% of cases). * **Clinical presentation:** Failure to pass meconium within the first 48 hours, abdominal distension, and "blast sign" (explosive passage of stool on digital rectal exam). * **Associated condition:** Down Syndrome (Trisomy 21) is seen in ~10% of cases. * **Gold Standard:** Rectal Biopsy (Suction biopsy is preferred as it doesn't require anesthesia).

Question 123: In children, the presence of increased fecal fat excretion and increased fecal nitrogen levels is a feature of all the following conditions except?

A. Pancreatic insufficiency
B. Bacterial overgrowth syndrome
C. Celiac disease
D. Ulcerative colitis (Correct Answer)

Explanation: **Explanation:** The presence of both **increased fecal fat (steatorrhea)** and **increased fecal nitrogen (azotorrhea)** indicates a state of generalized malabsorption or maldigestion. **1. Why Ulcerative Colitis (UC) is the correct answer:** Ulcerative colitis is an inflammatory bowel disease primarily confined to the **mucosa of the colon**. Since the digestion and absorption of fats and proteins occur almost entirely in the small intestine, UC does not typically cause malabsorption of these nutrients. Patients with UC present with bloody diarrhea and tenesmus rather than steatorrhea. **2. Analysis of incorrect options:** * **Pancreatic Insufficiency (e.g., Cystic Fibrosis):** This is the classic cause of both steatorrhea and azotorrhea. The lack of lipase leads to fat maldigestion, while the lack of proteases (trypsin, chymotrypsin) leads to undigested proteins in the stool (increased fecal nitrogen). * **Bacterial Overgrowth Syndrome (SIBO):** Excess bacteria deconjugate bile salts (causing fat malabsorption) and compete for nutrients. They also cause mucosal damage and proteolysis of brush border enzymes, leading to increased fecal nitrogen. * **Celiac Disease:** This is a malabsorption syndrome caused by gluten-sensitive enteropathy. The destruction of small intestinal villi reduces the surface area for the absorption of all macronutrients, including fats and amino acids. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Steatorrhea:** 72-hour fecal fat estimation (>7g/day is abnormal). * **Azotorrhea:** Defined as fecal nitrogen excretion >2g/day. * **D-Xylose Test:** Used to differentiate mucosal causes (e.g., Celiac) from pancreatic causes of malabsorption. It is normal in pancreatic insufficiency but abnormal in mucosal diseases. * **Protein-Losing Enteropathy:** Associated with conditions like Menetrier’s disease or Lymphangiectasia; characterized by low serum albumin but not necessarily high fecal fat.

Question 124: What percentage of weight loss in infants constitutes severe dehydration?

A. >10% loss of body weight (Correct Answer)
B. >6% loss of body weight
C. 5% loss of body weight
D. 7% loss of body weight

Explanation: Dehydration in infants is classified based on the percentage of body weight lost, as infants have a higher proportion of total body water and are more susceptible to rapid fluid depletion. **Explanation of the Correct Answer:** * **Option A (>10% loss):** In infants, **severe dehydration** is defined as a loss of **>10%** of their body weight. At this stage, clinical signs include sunken fontanelles, very slow skin pinch (>2 seconds), lethargy or unconsciousness, and signs of hypovolemic shock (tachycardia, hypotension, and feeble pulses). Immediate IV fluid resuscitation (Plan C) is required. **Explanation of Incorrect Options:** * **Option C (5% loss):** This constitutes **Mild Dehydration** (or "No Dehydration" according to WHO IMNCI classification if clinical signs are absent). The infant is usually alert, thirsty, and has moist mucous membranes. * **Options B & D (6-9% loss):** These fall into the category of **Moderate Dehydration** (Some Dehydration). This is typically defined as a **6–9%** weight loss. Clinical features include irritability, sunken eyes, and a skin pinch that goes back slowly. **High-Yield Clinical Pearls for NEET-PG:** * **Classification Shift:** While traditional textbooks use Mild (5%), Moderate (10%), and Severe (15%) for older children, for **infants**, the threshold for severe is **>10%**. * **WHO IMNCI Classification:** * **No Dehydration:** <5% weight loss. * **Some Dehydration:** 5–10% weight loss. * **Severe Dehydration:** >10% weight loss. * **Gold Standard:** The most accurate way to assess the degree of dehydration is the **pre-illness weight minus the current weight**. * **Best Clinical Sign:** In clinical practice, **prolonged capillary refill time**, abnormal skin turgor, and abnormal respiratory patterns are the most reliable predictors of dehydration >5%.

Question 125: All of the following are true about Reye's syndrome, EXCEPT?

A. Follows viral infection
B. Associated with salicylate use
C. Should be treated as for hepatic failure
D. Good prognosis (Correct Answer)

Explanation: **Explanation:** Reye’s syndrome is a rare but life-threatening condition characterized by **acute non-inflammatory encephalopathy** and **fatty degeneration of the liver**. **Why "Good prognosis" is the correct (False) statement:** The prognosis of Reye’s syndrome is generally **poor**, especially if not diagnosed early. It carries a high mortality rate (approximately 20–40%), and survivors often suffer from permanent neurological sequelae due to severe cerebral edema and increased intracranial pressure. **Analysis of other options:** * **Option A (Follows viral infection):** It typically occurs following a prodromal viral illness, most commonly **Influenza B** or **Varicella**. * **Option B (Associated with salicylate use):** There is a strong epidemiological link between the administration of **aspirin (salicylates)** during a viral illness and the development of Reye’s syndrome. This has led to the recommendation of using Acetaminophen/Ibuprofen instead for pediatric fever. * **Option C (Treated as for hepatic failure):** Management is supportive and mirrors that of acute liver failure, focusing on maintaining glucose levels (to prevent hypoglycemia) and aggressive management of **cerebral edema** (using mannitol, hyperventilation, or fluid restriction). **High-Yield Clinical Pearls for NEET-PG:** * **Pathophysiology:** Mitochondrial dysfunction leading to impaired fatty acid oxidation. * **Liver Biopsy Findings:** Characterized by **microvesicular steatosis** (small fat droplets) without significant inflammation or necrosis. * **Biochemical markers:** Elevated serum ammonia, prolonged PT/INR, and elevated AST/ALT, but notably, **bilirubin levels are usually normal or only mildly elevated** (unlike typical hepatitis). * **Drug of Choice for Fever in Children:** Paracetamol (to avoid Reye's).

Question 126: What is the most likely diagnosis in a 26-day-old infant presenting with recurrent non-bilious vomiting, constipation, and weight loss?

A. Esophageal atresia
B. Annular pancreas
C. Ileal atresia
D. Pyloric stenosis (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Pyloric stenosis** **Why it is correct:** Infantile Hypertrophic Pyloric Stenosis (IHPS) typically presents between **3 to 6 weeks of life** (average 21–30 days). The hallmark clinical feature is **recurrent, non-bilious, projectile vomiting** occurring immediately after feeds. The infant remains hungry ("hungry vomiter"), leading to poor weight gain, dehydration, and constipation (due to lack of bolus reaching the lower GI tract). The underlying pathology is hypertrophy of the pyloric sphincter muscles, causing gastric outlet obstruction. **Why the other options are incorrect:** * **A. Esophageal atresia:** Usually presents in the **first hours of life** with excessive salivation, drooling, and choking/cyanosis during the very first feed. * **B. Annular pancreas:** This causes duodenal obstruction. Since the obstruction is typically distal to the ampulla of Vater, it usually presents with **bilious vomiting** shortly after birth. * **C. Ileal atresia:** This is a distal small bowel obstruction presenting within the **first 24–48 hours** of life with abdominal distension and **bilious vomiting**. **NEET-PG High-Yield Pearls:** * **Metabolic Profile:** Hypochloremic, hypokalemic, metabolic alkalosis with paradoxical aciduria. * **Physical Exam:** A palpable, olive-shaped mass in the epigastrium and visible gastric peristalsis. * **Diagnosis:** Ultrasound is the investigation of choice (Pyloric muscle thickness >4mm or length >14mm). * **Management:** Initial step is fluid resuscitation (Normal Saline); definitive treatment is **Ramstedt’s Pyloromyotomy**.

Question 127: What is the characteristic finding of sweat chloride levels in patients with cystic fibrosis?

A. Decreased
B. Increased (Correct Answer)
C. No change
D. May increase or decrease

Explanation: **Explanation:** The correct answer is **B. Increased**. **Underlying Medical Concept:** Cystic Fibrosis (CF) is caused by a mutation in the **CFTR (Cystic Fibrosis Transmembrane Conductance Regulator)** gene. In the sweat glands, the normal function of the CFTR protein is to **reabsorb** chloride (and secondarily sodium) from the primary secretion as it moves through the duct toward the skin surface. In CF patients, this protein is defective or absent, preventing the reabsorption of chloride. Consequently, chloride remains in the sweat, leading to the characteristic "salty sweat" and elevated sweat chloride levels. **Analysis of Options:** * **A. Decreased:** This is incorrect because the defect lies in the inability to reabsorb chloride from the lumen; thus, levels cannot be lower than normal. * **C. No change:** This is incorrect as sweat chloride is the "gold standard" diagnostic marker for CF due to its consistent elevation. * **D. May increase or decrease:** This is incorrect because the pathophysiology of CFTR in sweat glands leads specifically to a failure of reabsorption, resulting in a predictable increase. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Threshold:** A sweat chloride concentration **≥ 60 mmol/L** on two separate occasions (using Pilocarpine Iontophoresis) is diagnostic for CF. * **Borderline values:** 30–59 mmol/L in infants <6 months or 40–59 mmol/L in older individuals warrant further genetic testing. * **Contrast with Lungs:** In the respiratory epithelium, CFTR normally *secretes* chloride. Therefore, CF leads to thick, dehydrated mucus in the lungs but salty sweat on the skin. * **False Positives:** Conditions like untreated adrenal insufficiency, nephrogenic diabetes insipidus, and malnutrition can sometimes cause elevated sweat chloride.

Question 128: A 3-month-old baby refuses breast milk since the 2nd day of birth, accepts glucose-water, develops vomiting and severe jaundice by the 5th day. Benedict's test was positive for urine and blood glucose was low. What is the most likely cause due to deficiency of?

A. Galactose-1-phosphate uridyl transferase (Correct Answer)
B. Beta galactosidase
C. Glucose-6-phosphatase
D. Galactokinase

Explanation: ### Explanation The clinical presentation describes a classic case of **Classic Galactosemia**, caused by a deficiency of the enzyme **Galactose-1-phosphate uridyl transferase (GALT)**. **1. Why Option A is Correct:** In Classic Galactosemia, the inability to metabolize galactose leads to the accumulation of **Galactose-1-phosphate** in tissues (liver, brain, kidneys). * **Symptoms:** Onset occurs shortly after starting milk (lactose = glucose + galactose). Symptoms include vomiting, jaundice (conjugated/unconjugated), hepatomegaly, and hypoglycemia. * **Diagnostic Clue:** The **Benedict’s test** detects reducing substances in urine. Since galactose is a reducing sugar but not glucose (as confirmed by low blood glucose), a positive Benedict’s test in the presence of hypoglycemia is a hallmark of this condition. **2. Why Other Options are Incorrect:** * **Beta-galactosidase (B):** Deficiency causes GM1 gangliosidosis or Morquio syndrome type B, not acute neonatal jaundice and hypoglycemia. * **Glucose-6-phosphatase (C):** Deficiency causes **Von Gierke Disease** (GSD Type I). While it presents with severe hypoglycemia and hepatomegaly, it typically appears around 3–6 months of age (when feeding intervals lengthen) and does not cause a positive Benedict's test for galactose. * **Galactokinase (D):** Deficiency leads to **Galactokinase deficiency**, a milder form of galactosemia. It presents primarily with **cataracts** (due to galactitol) but lacks the severe systemic toxicity (jaundice, liver failure, hypoglycemia) seen in GALT deficiency. **3. NEET-PG High-Yield Pearls:** * **Most common enzyme deficiency:** GALT (Classic Galactosemia). * **Early Sign:** Oil-drop cataracts (due to accumulation of galactitol in the lens). * **Infection Risk:** These infants are at high risk for **E. coli neonatal sepsis**. * **Management:** Immediate withdrawal of breast milk and initiation of a **soy-based (lactose-free) formula**. * **Screening:** Benedict’s test is positive, but the **Glucose Oxidase test (dipstick)** is negative (specific for glucose).

Question 129: Which of the following cereals is an exception and can be consumed by patients with celiac disease?

A. Wheat
B. Barley
C. Maize (Correct Answer)
D. Rye

Explanation: **Explanation:** Celiac disease (Gluten-sensitive enteropathy) is an autoimmune-mediated inflammatory disorder of the small intestine triggered by the ingestion of **prolamins** (gluten proteins) in genetically susceptible individuals (HLA-DQ2/DQ8). The mainstay of treatment is a lifelong, strict gluten-free diet. **Why Maize is the Correct Answer:** Maize (corn) and Rice are safe for celiac patients because they do not contain the specific toxic prolamin fractions that trigger the immune response. While maize does contain a protein called "zein," it lacks the specific amino acid sequences found in wheat, barley, and rye that cause intestinal villous atrophy. **Why Other Options are Incorrect:** The "toxic" cereals that must be strictly avoided can be remembered by the mnemonic **BROW**: * **B - Barley:** Contains the prolamin **Hordein**. * **R - Rye:** Contains the prolamin **Secalin**. * **O - Oats:** Historically avoided due to cross-contamination with wheat; however, pure oats (Avenin) are tolerated by most, though still controversial in some guidelines. * **W - Wheat:** Contains the prolamin **Gliadin**, which is the most potent trigger for celiac disease. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Endoscopic small bowel biopsy showing **Villous atrophy**, Crypt hyperplasia, and increased Intraepithelial lymphocytes (Marsh Criteria). * **Best Screening Test:** Anti-tissue Transglutaminase (anti-tTG) IgA antibodies. * **Associated Conditions:** Dermatitis herpetiformis (itchy vesicles on elbows/knees), Type 1 Diabetes, and Down Syndrome. * **Safe Alternatives:** Rice, Maize (Corn), Millets (Jowar, Bajra), Soy, and Potato.

Question 130: Which of the following is NOT a gastrointestinal disturbance seen in cystic fibrosis?

A. Spleen infarct (Correct Answer)
B. Biliary cirrhosis
C. Malabsorption
D. Gall stones

Explanation: **Explanation:** Cystic Fibrosis (CF) is a multisystem disorder caused by a mutation in the **CFTR gene**, leading to thick, viscid secretions that obstruct various organ ducts. While it primarily affects the lungs and the gastrointestinal tract, **splenic infarction is NOT a typical feature of CF.** **Why Spleen Infarct is the Correct Answer:** Splenic infarction is commonly associated with hematological conditions like Sickle Cell Anemia or embolic events (e.g., infective endocarditis). In CF, the spleen is usually affected secondary to **portal hypertension** (due to biliary cirrhosis), which leads to **splenomegaly** (enlargement) rather than infarction. **Analysis of Incorrect Options:** * **Biliary Cirrhosis:** Thickened bile (gallbladder sludge) causes obstruction of the intrahepatic bile ducts, leading to focal biliary cirrhosis. Over time, this can progress to multinodular cirrhosis and portal hypertension. * **Malabsorption:** This is the most common GI manifestation. Viscous secretions block pancreatic ducts, causing **exocrine pancreatic insufficiency**. This leads to fat malabsorption, steatorrhea, and deficiencies of fat-soluble vitamins (A, D, E, K). * **Gallstones:** Dehydration of bile and altered bile acid metabolism significantly increase the incidence of cholelithiasis (gallstones) in CF patients. **High-Yield Clinical Pearls for NEET-PG:** * **Meconium Ileus:** The earliest GI manifestation of CF (seen in 15-20% of newborns). * **DIOS (Distal Intestinal Obstruction Syndrome):** A unique form of constipation/obstruction seen in older CF patients. * **Rectal Prolapse:** A classic clinical sign in undiagnosed CF children due to bulky stools and poor muscle tone. * **Diagnosis:** Sweat Chloride test (>60 mEq/L) remains the gold standard.

Practice by Chapter

Gastroesophageal Reflux

Practice Questions

Peptic Ulcer Disease

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Inflammatory Bowel Disease

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Celiac Disease

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Malabsorption Syndromes

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Acute and Chronic Diarrhea

Practice Questions

Constipation and Encopresis

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Gastrointestinal Bleeding

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Intestinal Obstruction

Practice Questions

Liver Diseases in Children

Practice Questions

Pancreatic Disorders

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Pediatric Nutritional Support

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