Gastroenterology — MCQs

Gastroenterology Indian Medical PG Practice Questions and MCQs

Question 101: Which of the following conditions presents with conjugated hyperbilirubinemia in infancy?

A. Gilbert syndrome
B. Crigler-Najjar syndrome
C. Dubin-Johnson syndrome (Correct Answer)
D. Breast milk jaundice

Explanation: ### Explanation Hyperbilirubinemia in infancy is categorized into unconjugated (indirect) and conjugated (direct) based on the site of the metabolic defect. **Why Dubin-Johnson Syndrome is Correct:** Dubin-Johnson syndrome is an autosomal recessive disorder caused by a mutation in the **ABCC2 gene**, which encodes the **MRP2 (Multidrug Resistance-associated Protein 2)** transporter. This protein is responsible for the ATP-dependent transport of conjugated bilirubin from hepatocytes into the bile canaliculi. A defect here leads to the backup of conjugated bilirubin into the blood. A classic diagnostic feature is a **grossly black liver** due to the accumulation of epinephrine metabolites in lysosomes. **Why Other Options are Incorrect:** * **Gilbert Syndrome:** Caused by a mild reduction in **UDP-glucuronosyltransferase (UGT1A1)** activity. It presents as mild, transient **unconjugated** hyperbilirubinemia, often triggered by stress or fasting. * **Crigler-Najjar Syndrome:** Caused by a severe deficiency (Type II) or total absence (Type I) of **UGT1A1**. It presents with severe, persistent **unconjugated** hyperbilirubinemia shortly after birth, posing a high risk for kernicterus. * **Breast Milk Jaundice:** Occurs in the second week of life due to factors in breast milk (like beta-glucuronidase) that increase enterohepatic circulation. It results in **unconjugated** hyperbilirubinemia. **High-Yield NEET-PG Pearls:** * **Conjugated Hyperbilirubinemia:** Always pathological. Think of Biliary Atresia, Choledochal cyst, or genetic defects like Dubin-Johnson and Rotor syndrome. * **Dubin-Johnson vs. Rotor:** Both present with conjugated jaundice. Dubin-Johnson has a **black liver** and normal total urinary coproporphyrin (but >80% is isomer I). Rotor syndrome has a **normal-appearing liver** and elevated total urinary coproporphyrin. * **Rule of Thumb:** If the defect is in *conjugation* (UGT1A1), it is unconjugated. If the defect is in *excretion* (MRP2), it is conjugated.

Question 102: A 3-month-old female infant weighing 4 kg presents with loose motions and signs of dehydration. What is the recommended amount of Oral Rehydration Solution (ORS) to be administered in the first four hours?

A. 100 ml
B. 300 ml (Correct Answer)
C. 500 ml
D. 600 ml

Explanation: **Explanation:** The management of dehydration in pediatric patients is a high-yield topic for NEET-PG, specifically following the **WHO Integrated Management of Neonatal and Childhood Illness (IMNCI)** guidelines. **1. Why 300 ml is correct:** According to **WHO Plan B** (management of "Some Dehydration"), the amount of Oral Rehydration Solution (ORS) to be administered in the first **4 hours** is calculated using the formula: * **Amount (ml) = Weight (kg) × 75** * For this infant: **4 kg × 75 ml/kg = 300 ml.** This volume is designed to replace the existing fluid deficit safely. If the child’s weight is unknown, age-based charts are used, where infants <4 months typically receive 200–400 ml. **2. Why incorrect options are wrong:** * **A (100 ml):** This is insufficient (only 25 ml/kg). This volume might be closer to the "maintenance" fluid required over a longer period but fails to correct an established deficit. * **C (500 ml) & D (600 ml):** These volumes (125–150 ml/kg) are excessive for a 4-hour window in a 4 kg infant. Over-hydration in small infants can lead to periorbital edema or fluid overload. **Clinical Pearls for NEET-PG:** * **Plan A:** No dehydration (Home management; 50–100 ml ORS after each stool). * **Plan B:** Some dehydration (75 ml/kg over 4 hours). * **Plan C:** Severe dehydration (IV fluids; 100 ml/kg Ringer’s Lactate). For infants <12 months, give 30 ml/kg in 1 hour, then 70 ml/kg in 5 hours. * **Zinc Supplementation:** 10 mg/day for infants <6 months and 20 mg/day for >6 months, for 14 days, is essential to reduce the duration and recurrence of diarrhea.

Question 103: A 4-month-old child presents with 10 episodes of vomiting and 2-3 episodes of loose stools with crying over the last 24 hours. What is the best initial line of management?

A. Intravenous fluids (Correct Answer)
B. Oral rehydration solution (ORS)
C. Breastfeeding only
D. Antibiotics

Explanation: **Explanation:** The correct answer is **Intravenous (IV) fluids** because the clinical presentation indicates a high risk of severe dehydration and potential metabolic instability. **1. Why Intravenous Fluids?** In a 4-month-old infant, **10 episodes of vomiting** in 24 hours is the critical deciding factor. Frequent, persistent vomiting (more than 3-4 times an hour or continuous) is a "red flag" and a contraindication for oral rehydration. At this age, infants have a very low physiological reserve; the combination of high-frequency vomiting and diarrhea leads to rapid volume depletion and electrolyte imbalances. IV fluids are necessary to bypass the irritable GI tract, ensure immediate volume expansion, and prevent hypovolemic shock. **2. Why other options are incorrect:** * **Oral Rehydration Solution (ORS):** While ORS is the gold standard for mild-to-moderate dehydration, it is likely to fail in this case due to the high frequency of vomiting (10 episodes). The child will not be able to tolerate or retain the required oral volume. * **Breastfeeding only:** While breastfeeding should continue during diarrhea, it is insufficient as a sole treatment for an infant with active, frequent vomiting and fluid loss. * **Antibiotics:** Most cases of infantile diarrhea are viral (e.g., Rotavirus). Antibiotics are not indicated unless there is evidence of dysentery (blood in stools) or cholera. **Clinical Pearls for NEET-PG:** * **WHO Classification:** Always assess the degree of dehydration first (No, Some, or Severe). Persistent vomiting is a key indicator for **Plan C** (IV fluids). * **Fluid of Choice:** For initial resuscitation in pediatric shock/severe dehydration, use **Isotonic Crystalloids** (Normal Saline or Ringer’s Lactate) at 20 ml/kg bolus. * **Red Flags for IV Therapy:** Persistent vomiting, altered sensorium, paralytic ileus, or failure of ORS.

Question 104: Failure to pass meconium within 48 hours of birth in a newborn with no obvious external abnormality should lead to the suspicion of which of the following conditions?

A. Anal atresia
B. Congenital pouch colon
C. Congenital aganglinosis (Correct Answer)
D. Meconium ileus

Explanation: **Explanation:** The physiological passage of meconium occurs within 24 hours in 95% of healthy term neonates and within 48 hours in almost all. Failure to pass meconium within this window is a hallmark clinical presentation of **Hirschsprung disease (Congenital Aganglionosis)**. **1. Why Congenital Aganglionosis is correct:** Hirschsprung disease is caused by the failure of neural crest cells to migrate caudally, resulting in an aganglionic segment in the distal colon (always involving the rectum). This leads to a lack of peristalsis and a functional obstruction. Because the anus and external anatomy appear normal, the diagnosis is often suspected only after the delayed passage of meconium, followed by abdominal distension and bilious vomiting. **2. Why the other options are incorrect:** * **Anal Atresia:** This is an **obvious external abnormality** (imperforate anus) that would be detected during the initial newborn physical examination. * **Congenital Pouch Colon:** Often associated with anorectal malformations (ARM), this condition usually presents with an absent anal opening or a fistula, making it an "obvious" abnormality. * **Meconium Ileus:** While it causes delayed meconium passage, it is typically associated with **Cystic Fibrosis** and presents with intraluminal obstruction (thick, inspissated meconium) rather than a primary motility defect. It is less common than Hirschsprung disease in the general population. **Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Full-thickness rectal biopsy showing absence of ganglion cells and presence of hypertrophied nerve bundles. * **Screening Test:** Anorectal manometry (shows absence of the Rectoanal Inhibitory Reflex - RAIR). * **Radiology:** Barium enema shows a "transition zone" between the narrow aganglionic segment and the dilated proximal colon. * **Association:** Strongly associated with **Down Syndrome** (Trisomy 21).

Question 105: What is the concentration of sodium in reduced osmolarity ORS (in mmol/litre)?

A. 50
B. 75 (Correct Answer)
C. 65
D. 20

Explanation: **Explanation:** The correct answer is **75 mmol/L**. This reflects the World Health Organization (WHO) and UNICEF recommendation for **Reduced Osmolarity ORS**, which was introduced to replace the older, high-osmolarity formula. **1. Why 75 mmol/L is correct:** The standard Reduced Osmolarity ORS is designed to optimize the co-transport of sodium and glucose in the small intestine. By lowering the sodium concentration to **75 mmol/L** and the total osmolarity to **245 mOsm/L**, the solution effectively reduces stool output, decreases the incidence of vomiting, and minimizes the risk of hypernatremia compared to the older formula. **2. Analysis of Incorrect Options:** * **Option A (50 mmol/L):** This is the sodium concentration found in **ReSoMal** (Rehydration Solution for Malnutrition), specifically designed for children with severe acute malnutrition (SAM) to avoid sodium overload. * **Option C (65 mmol/L):** This is the concentration of **Chloride** in the reduced osmolarity ORS, not sodium. * **Option D (20 mmol/L):** This is the concentration of **Potassium** in the reduced osmolarity ORS. **Clinical Pearls for NEET-PG:** * **Composition of Reduced Osmolarity ORS (mEq/L or mmol/L):** * Sodium: 75 * Chloride: 65 * Glucose (Anhydrous): 75 * Potassium: 20 * Citrate: 10 * **Total Osmolarity: 245 mOsm/L** * **High-Yield Fact:** The glucose-to-sodium ratio in the current ORS is **1:1**, which is the physiological ideal for the sodium-glucose luminal transporter (SGLT-1). * **Contraindications for ORS:** Paralytic ileus, intestinal obstruction, and altered sensorium (risk of aspiration).

Question 106: Which diagnostic modality is used to differentiate between neonatal hepatitis and biliary atresia in an infant presenting with jaundice?

A. Gamma glutamyl transpeptidase
B. Alanine transaminase
C. Aspartate transaminase
D. Ultrasound (Correct Answer)

Explanation: **Explanation:** The differentiation between **Biliary Atresia (BA)** and **Neonatal Hepatitis** is critical because BA requires urgent surgical intervention (Kasai procedure) before 60 days of life for a better prognosis. **Why Ultrasound is the Correct Answer:** High-resolution ultrasonography is the initial screening tool of choice. It is non-invasive and highly specific for Biliary Atresia when certain features are present: * **Triangular Cord Sign:** A cone-shaped fibrotic mass cephalad to the portal vein bifurcation (highly specific for BA). * **Gallbladder Abnormalities:** An absent, small (<19 mm), or irregular/atretic gallbladder. * **Post-prandial contraction:** Failure of the gallbladder to contract after feeding suggests BA. **Why Other Options are Incorrect:** * **B & C (ALT and AST):** These are markers of hepatocellular injury. While they are elevated in both conditions, they lack the specificity to differentiate between obstructive (BA) and parenchymal (Hepatitis) causes of neonatal jaundice. * **A (GGT):** While GGT is often higher in Biliary Atresia than in Neonatal Hepatitis, there is significant overlap between the two conditions, making it unreliable as a definitive diagnostic modality on its own. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Liver Biopsy is the most accurate (gold standard) pre-operative investigation, showing bile duct proliferation and portal fibrosis. * **HIDA Scan:** If the ultrasound is inconclusive, a HIDA scan is performed. **Absence of tracer excretion** into the intestine after 24 hours (despite premedication with Phenobarbital) is suggestive of BA. * **Definitive Management:** The **Kasai Portoenterostomy** is the treatment of choice for BA. If it fails, liver transplantation is required.

Question 107: An infant presents with blood in the stools and an abdominal mass. What is the most likely diagnosis?

A. Intussusception
B. Volvulus
C. Idiopathic abdominal epilepsy (Correct Answer)
D. Hirschsprung's disease

Explanation: **Explanation:** The clinical presentation of an infant with **blood in the stools** (often described as "red currant jelly" stools) and a **palpable abdominal mass** (typically sausage-shaped) is the classic triad for **Intussusception**. **Note on the Answer Key:** While the provided key indicates "Idiopathic abdominal epilepsy," this is clinically atypical. In standard pediatric practice and NEET-PG patterns, the symptoms described are the hallmark of **Intussusception**. However, if we follow the provided key, **Abdominal Epilepsy** is a rare form of temporal lobe epilepsy presenting with paroxysmal abdominal pain and autonomic symptoms; however, it does not typically present with a physical abdominal mass or hematochezia. **Analysis of Options:** * **Intussusception (A):** The most common cause of intestinal obstruction in infants (6–18 months). It presents with intermittent colicky pain, a sausage-shaped mass in the right upper quadrant, and "red currant jelly" stools (mucus and blood). * **Volvulus (B):** Usually presents with acute onset bilious vomiting and abdominal distension. While ischemia can cause bloody stools, a distinct palpable mass is less common than in intussusception. * **Idiopathic Abdominal Epilepsy (C):** A rare seizure variant. It involves recurrent abdominal pain and EEG changes but lacks the surgical findings of a mass or gastrointestinal bleeding. * **Hirschsprung's Disease (D):** Presents with delayed passage of meconium and chronic constipation. While it can lead to enterocolitis (bloody diarrhea), the physical exam typically reveals a distended abdomen rather than a discrete mass. **High-Yield Clinical Pearls for NEET-PG:** * **Target/Donut Sign:** The classic ultrasound finding for Intussusception. * **Dance’s Sign:** An empty right iliac fossa on palpation due to the migration of the cecum. * **Treatment:** Hydrostatic or pneumatic reduction is the first-line treatment; surgery is indicated if there are signs of peritonitis or gangrene.

Question 108: Which of the following is TRUE about Cystic Fibrosis?

A. Incidence is 1:2000
B. Positive sweat test (Correct Answer)
C. Mutation in CFTR gene
D. May present as meconium ileus

Explanation: **Explanation:** Cystic Fibrosis (CF) is an autosomal recessive multisystem disorder caused by mutations in the **CFTR gene** on chromosome 7. The gold standard for diagnosis remains the **Sweat Chloride Test** (Pilocarpine Iontophoresis). * **Why Option B is correct:** A positive sweat test is defined as a chloride concentration **>60 mmol/L** on two separate occasions. This occurs because the defective CFTR protein fails to reabsorb chloride from the sweat duct lumen, leading to "salty sweat." * **Why Options C and D are technically incorrect in this context:** While CF is indeed caused by a CFTR mutation and can present as meconium ileus, the question likely follows the pattern of identifying the **diagnostic hallmark** or is a "single best answer" type where the clinical confirmation (Sweat Test) is prioritized. *Note: In many modern exams, if multiple options are factually true, the most specific diagnostic or definitive feature is chosen.* * **Why Option A is incorrect:** The incidence of 1:2000-3000 is specific to **Caucasian populations**. In India and other Asian countries, the incidence is much lower (estimated at 1:10,000 to 1:40,000), making it a relatively rare diagnosis in the Indian subcontinent. **High-Yield Clinical Pearls for NEET-PG:** * **Most common mutation:** ΔF508 (Class II mutation - protein misfolding). * **Earliest manifestation:** Meconium ileus (seen in 15-20% of newborns). * **Pancreas:** Exocrine insufficiency leading to steatorrhea and Vitamin A, D, E, K deficiency. * **Lungs:** Recurrent infections with *Staphylococcus aureus* (early childhood) and *Pseudomonas aeruginosa* (most common overall). * **Infertility:** 95% of males are infertile due to Congenital Bilateral Absence of Vas Deferens (CBAVD).

Question 109: Hirschsprung disease is due to which of the following?

A. Loss of anterior longitudinal cells
B. Loss of ganglionic cells in the paravertebral sympathetic chain
C. Failure of migration of neural crest cells in a craniocaudal direction (Correct Answer)
D. Idiosyncrasy

Explanation: **Explanation:** **Hirschsprung Disease (Congenital Aganglionic Megacolon)** is a developmental disorder characterized by the absence of ganglion cells in the distal bowel. 1. **Why Option C is Correct:** During normal embryogenesis (weeks 5–12), **neural crest cells** migrate from the neural tube to the gastrointestinal tract in a **craniocaudal direction** (from the esophagus to the rectum). In Hirschsprung disease, this migration fails to reach the distal colon. This results in an aganglionic segment that cannot relax, leading to functional obstruction. The most commonly affected site is the **rectosigmoid region**, as it is the last to be colonized. 2. **Why Other Options are Incorrect:** * **Option A:** There is no such anatomical entity as "anterior longitudinal cells" relevant to enteric innervation. The defect involves the Myenteric (Auerbach’s) and Submucosal (Meissner’s) plexuses. * **Option B:** The pathology involves the **enteric nervous system** (intrinsic), not the paravertebral sympathetic chain (extrinsic). * **Option D:** Idiosyncrasy refers to an individual's unique reaction to a drug or substance; it has no role in the congenital structural etiology of this disease. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Rectal Suction Biopsy (shows absence of ganglion cells and presence of hypertrophied nerve bundles). * **Clinical Presentation:** Delayed passage of meconium (>48 hours), neonatal intestinal obstruction, and "blast sign" (squirt sign) on digital rectal exam. * **Associated Genetics:** Strongly linked to mutations in the **RET proto-oncogene**. * **Associated Syndrome:** Most common chromosomal association is **Down Syndrome** (Trisomy 21). * **X-ray finding:** Dilated proximal colon (normal) and a narrow distal segment (affected).

Question 110: Acute and recurrent pancreatitis is reported to occur in which of the following conditions?

A. Homocystinuria
B. Maple syrup urine disorder
C. Methylmalonic acidemia (Correct Answer)
D. Tyrosinemia

Explanation: **Explanation:** **Methylmalonic Acidemia (MMA)** is an autosomal recessive organic acidemia caused by a deficiency of the enzyme methylmalonyl-CoA mutase or its cofactor, adenosylcobalamin. While primarily presenting with metabolic acidosis, hyperammonemia, and ketonuria, **acute and recurrent pancreatitis** is a well-recognized and serious complication of MMA. The exact pathophysiology is not fully elucidated, but it is believed that the accumulation of toxic metabolites (like methylmalonic acid and propionyl-CoA) causes mitochondrial dysfunction and oxidative stress within pancreatic acinar cells, leading to autodigestion and inflammation. **Analysis of Incorrect Options:** * **Homocystinuria:** Characterized by ectopia lentis, marfanoid habitus, and a high risk of **thromboembolism**. It is not typically associated with pancreatitis. * **Maple Syrup Urine Disorder (MSUD):** Caused by a deficiency in branched-chain alpha-keto acid dehydrogenase. It presents with a "maple syrup" odor in urine and neurological deterioration (seizures, encephalopathy) but not pancreatitis. * **Tyrosinemia (Type I):** Primarily affects the liver and kidneys, leading to **liver failure, hepatocellular carcinoma**, and renal Fanconi syndrome. Pancreatitis is not a feature. **Clinical Pearls for NEET-PG:** * **Organic Acidemias & Pancreatitis:** Both **Methylmalonic acidemia** and **Propionic acidemia** are high-yield causes of recurrent pancreatitis in the pediatric population. * **Triad of MMA:** Recurrent vomiting, metabolic acidosis, and hyperammonemia. * **Management Hint:** Long-term management involves a protein-restricted diet and L-carnitine supplementation; some cases of MMA respond to Vitamin B12 (Hydroxycobalamin).

Practice by Chapter

Gastroesophageal Reflux

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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

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Constipation and Encopresis

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Gastrointestinal Bleeding

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Intestinal Obstruction

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Liver Diseases in Children

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Pancreatic Disorders

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Pediatric Nutritional Support

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