Gastroenterology Practice Questions

Q: Convulsions in a child with dehydration and vomiting can only be due to:

Decreased serum sodium. **Explanation:** In a child presenting with dehydration and vomiting, electrolyte imbalances are common. The occurrence of **convulsions** is most characteristically associated with **Hyponatremia (Decreased serum sodium)**. **1. Why Hyponatremia is the correct answer:** Sodium is the primary extracellular osmolite. When serum sodium levels drop rapidly (often due to loss of sodium in vomitus/diarrhea or replacement with hypotonic fluids), an osmotic gradient is created. Water moves from the extracellular space into the brain cells (intracellular space) to equalize osmolality, leading to **cerebral edema**. This increased intracranial pressure and neuronal swelling trigger seizures. **2. Why the other options are incorrect:** * **Decreased serum magnesium (Hypomagnesemia):** While it can cause seizures, it is rarely the primary consequence of simple dehydration and vomiting; it is more common in malabsorption syndromes or specific renal losses. * **Decreased serum potassium (Hypokalemia):** This is very common in vomiting/dehydration, but it typically manifests as **muscle weakness, paralytic ileus, and ECG changes** (U waves), not convulsions. * **Decreased serum chloride (Hypochloremia):** This leads to metabolic alkalosis (contraction alkalosis), which may cause tetany due to decreased ionized calcium, but it is not a direct cause of seizures. **Clinical Pearls for NEET-PG:** * **Hyponatremic Dehydration:** Defined as Serum $Na^+ < 130$ mEq/L. It is the most dangerous form of dehydration because of the risk of seizures. * **Hypernatremic Dehydration:** Can also cause seizures, but these occur due to **cerebral shrinkage** and subarachnoid hemorrhage rather than edema. * **Management Tip:** Rapid correction of chronic hyponatremia can lead to **Central Pontine Myelinolysis**, whereas rapid correction of hypernatremia can lead to **Cerebral Edema**.

Q: Fecal soiling in children is most commonly due to?

Chronic constipation. ### Explanation **Correct Answer: B. Chronic constipation** **Mechanism of Fecal Soiling (Encopresis):** The most common cause of fecal soiling in children is **functional chronic constipation** (accounting for >90% of cases). When a child chronically withholds stool, the rectum becomes distended, leading to a "megarectum." Over time, the rectal wall loses its sensitivity and contractile strength. Eventually, liquid or semi-formed stool from higher up in the colon leaks around the hard, impacted fecal mass and escapes through the anal sphincter involuntarily. This is known as **overflow incontinence** or encopresis. **Why other options are incorrect:** * **A. Hirschsprung's Disease:** While this involves severe constipation, fecal soiling is **extremely rare** in Hirschsprung’s. This is because the aganglionic segment (usually the distal rectum) remains tonically contracted, preventing the passage of even liquid stool. The absence of soiling is a key clinical feature used to differentiate Hirschsprung’s from functional constipation. * **C. Rectal Atresia:** This is a structural congenital anomaly presenting in the neonatal period with intestinal obstruction. It does not typically present as chronic soiling in an older child. **Clinical Pearls for NEET-PG:** * **Functional Constipation:** Usually starts after 2 years of age (often during toilet training); fecal soiling is common; dilated rectum filled with stool on PR exam. * **Hirschsprung’s Disease:** Usually presents in the neonatal period (delayed passage of meconium >48 hours); empty rectum on PR exam; "blast sign" (explosive release of gas/stool) upon finger withdrawal. * **Gold Standard Diagnosis for Hirschsprung’s:** Rectal suction biopsy (showing absence of ganglion cells and hypertrophied nerve bundles).

Q: A newborn presenting with intestinal obstruction and constipation showed, on abdominal X ray, multiple air fluid levels. Which of the following is NOT a likely diagnosis?

Pyloric obstruction. **Explanation:** The presence of **multiple air-fluid levels** on an abdominal X-ray indicates a **low intestinal obstruction** (distal to the duodenum). In such cases, air and fluid accumulate in multiple dilated loops of the small and/or large bowel. **1. Why Pyloric Obstruction is the correct answer:** Congenital Hypertrophic Pyloric Stenosis (CHPS) or pyloric atresia causes a **high gastric outlet obstruction**. Since the blockage is at the level of the stomach, air cannot pass into the distal intestines. An X-ray typically shows a single large gastric air bubble with a "gasless abdomen" distally. Therefore, multiple air-fluid levels are never seen in pyloric obstruction. **2. Analysis of Incorrect Options:** * **Duodenal Atresia:** While classically associated with the "double bubble" sign, if there is a partial obstruction or distal communication, some air can pass, though it typically shows limited fluid levels. However, in the context of this question, it is a more distal site than the pylorus. * **Ileal Atresia:** This is a classic cause of low intestinal obstruction. It presents with numerous dilated loops of small bowel and multiple air-fluid levels on an erect film. * **Ladd’s Bands:** Associated with malrotation, these bands can compress the duodenum or lead to midgut volvulus. This results in varying degrees of intestinal obstruction and can certainly present with multiple air-fluid levels if the obstruction is mid-jejunal or ileal. **Clinical Pearls for NEET-PG:** * **Double Bubble Sign:** Duodenal Atresia (associated with Down Syndrome). * **Triple Bubble Sign:** Jejunal Atresia. * **Ground Glass Appearance/Neuhauser Sign:** Meconium Ileus (Cystic Fibrosis). * **Egg-on-string Appearance:** Transposition of Great Arteries (Radiology overlap). * **Step-ladder pattern:** Characteristic of mechanical small bowel obstruction on X-ray.

Q: 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?

300 ml. **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 6 months, for 14 days, is essential to reduce the duration and recurrence of diarrhea.

Q: 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?

Intravenous fluids. **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.

Q: A 2-hour-old male infant was diagnosed in utero with polyhydramnios. He is vomiting stomach contents and bile, a condition that has continued for 2 days. Radiographic examination reveals a "double bubble" sign on ultrasound scan. The child cries consistently and is constantly hungry but has lost 300 g in weight. Which of the following conditions will most likely explain the symptoms?

Duodenal atresia. ### Explanation **Correct Answer: B. Duodenal atresia** **1. Why it is correct:** The clinical triad of **polyhydramnios** (due to inability to swallow/absorb amniotic fluid), **bilious vomiting** shortly after birth, and the pathognomonic **"double bubble" sign** on imaging is classic for duodenal atresia. The "double bubble" represents air in the dilated stomach and the proximal duodenum, with no distal gas. Since the obstruction is distal to the ampulla of Vater, the vomitus is typically bilious. The weight loss and hunger are expected consequences of complete intestinal obstruction. **2. Why the other options are incorrect:** * **A. Duodenal stenosis:** While it presents similarly, stenosis is a partial obstruction. It usually presents later in life (not at 2 hours) and often shows some distal gas on X-ray, unlike the complete obstruction seen here. * **C. Hypertrophied pyloric sphincter (IHPS):** This typically presents at **3–6 weeks** of age with **non-bilious** projectile vomiting. The "double bubble" sign is not seen; instead, a "string sign" or "olive-shaped mass" is characteristic. * **D. Atrophied gastric antrum:** This is not a standard clinical entity causing neonatal intestinal obstruction or the "double bubble" sign. **3. High-Yield Clinical Pearls for NEET-PG:** * **Association:** Approximately 30% of infants with duodenal atresia have **Down Syndrome (Trisomy 21)**. * **Embryology:** Caused by a failure of **recanalization** of the duodenum during the 8th–10th week of gestation. * **Management:** Initial management involves nasogastric decompression and IV fluids. The definitive surgical treatment is **Duodenoduodenostomy** (Diamond-shaped anastomosis). * **Differential for Double Bubble:** Duodenal atresia, Annular pancreas, and Malrotation with Midgut Volvulus (though volvulus is a surgical emergency requiring immediate Doppler USG).

Q: 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?

Congenital aganglinosis. **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).

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

Ultrasound. **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 1

Convulsions in a child with dehydration and vomiting can only be due to:

Accepted Answer

Decreased serum sodium

Answer

Decreased serum magnesium

Answer

Decreased serum potassium

Answer

Decreased serum chloride

Question 2

Fecal soiling in children is most commonly due to?

Accepted Answer

Chronic constipation

Answer

Hirschsprung's disease

Answer

Rectal atresia

Answer

None of the above

Question 3

A newborn presenting with intestinal obstruction and constipation showed, on abdominal X ray, multiple air fluid levels. Which of the following is NOT a likely diagnosis?

Accepted Answer

Pyloric obstruction

Answer

Duodenal atresia

Answer

Ileal atresia

Answer

Ladd's bands

Question 4

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

Accepted Answer

Dubin-Johnson syndrome

Answer

Gilbert syndrome

Answer

Crigler-Najjar syndrome

Answer

Breast milk jaundice

Question 5

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?

Accepted Answer

300 ml

Answer

100 ml

Answer

500 ml

Answer

600 ml

Question 6

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?

Accepted Answer

Intravenous fluids

Answer

Oral rehydration solution (ORS)

Answer

Breastfeeding only

Answer

Antibiotics

Question 7

A 2-hour-old male infant was diagnosed in utero with polyhydramnios. He is vomiting stomach contents and bile, a condition that has continued for 2 days. Radiographic examination reveals a "double bubble" sign on ultrasound scan. The child cries consistently and is constantly hungry but has lost 300 g in weight. Which of the following conditions will most likely explain the symptoms?

Accepted Answer

Duodenal atresia

Answer

Duodenal stenosis

Answer

Hypertrophied pyloric sphincter

Answer

Atrophied gastric antrum

Question 8

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?

Accepted Answer

Congenital aganglinosis

Answer

Anal atresia

Answer

Congenital pouch colon

Answer

Meconium ileus

Question 9

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

Accepted Answer

Ultrasound

Answer

Gamma glutamyl transpeptidase

Answer

Alanine transaminase

Answer

Aspartate transaminase

Question 10

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

Accepted Answer

Idiopathic abdominal epilepsy

Answer

Intussusception

Answer

Volvulus

Answer

Hirschsprung's disease

Gastroenterology — MCQs

Gastroenterology — MCQs

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