Gastroenterology Practice Questions

Q: A 23-year-old woman, G2, P1, gave birth at term to a boy of normal weight and length following an uncomplicated pregnancy. The infant initially did well, but at 6 weeks, he began feeding poorly for 1 week, and his mother noticed that much of the milk he ingested was forcefully vomited within 1 hour. Now, on physical examination, the infant is afebrile, and there are no external anomalies. A midabdominal mass is palpable. Bowel sounds are active. The medical history indicates that both the mother and her first child had the same illness during infancy. Which of the following conditions is most likely to explain these findings?

Pyloric stenosis. ### Explanation **Correct Option: D. Pyloric Stenosis** The clinical presentation is classic for **Infantile Hypertrophic Pyloric Stenosis (IHPS)**. The key diagnostic features in this case include: 1. **Age of onset:** Symptoms typically appear between **3 to 6 weeks** of life. 2. **Clinical feature:** **Non-bilious, projectile (forceful) vomiting** occurring shortly after feeds. 3. **Physical Exam:** A palpable "olive-shaped" midabdominal mass (hypertrophied pylorus) and visible gastric peristalsis. 4. **Genetics:** There is a known familial predisposition; if a mother had IHPS, the risk for her offspring is significantly higher (up to 20% for sons). **Why Incorrect Options are Wrong:** * **A. Annular Pancreas:** Usually presents in the early neonatal period with signs of duodenal obstruction. While it can cause non-bilious vomiting, it rarely presents as late as 6 weeks with a palpable mass. * **B. Diaphragmatic Hernia:** Typically presents at **birth** with respiratory distress, a scaphoid abdomen, and absent breath sounds on the affected side. It does not present with a palpable abdominal mass. * **C. Duodenal Atresia:** Presents within the **first 24–48 hours** of life with **bilious vomiting** (as the obstruction is distal to the ampulla of Vater). It is strongly associated with Down Syndrome and "double-bubble" sign on X-ray. **NEET-PG High-Yield Pearls:** * **Metabolic Abnormality:** The classic triad is **Hypochloremic, Hypokalemic, Metabolic Alkalosis** with paradoxical aciduria. * **Diagnosis:** Ultrasound is the investigation of choice (Pyloric muscle thickness >4mm or length >14mm). * **Barium Swallow:** Shows the "String sign," "Beak sign," or "Mushroom sign." * **Management:** Initial step is **fluid resuscitation** (Normal Saline); definitive treatment is **Ramstedt’s Pyloromyotomy**.

Q: A 6-year-old girl presents with constipation, abdominal distention, and vomiting. She is diagnosed with Hirschsprung disease (aganglionic megacolon), a congenital condition leading to colon dilation. This condition is caused by the absence of which of the following kinds of neural cell bodies?

Parasympathetic postganglionic neuron cell bodies. ### Explanation **Hirschsprung Disease (Congenital Aganglionic Megacolon)** is characterized by the failure of neural crest cells to migrate caudally during the 5th to 12th week of gestation. This results in the absence of the **enteric nervous system** (Auerbach’s and Meissner’s plexuses) in the distal colon. **1. Why Option D is Correct:** The enteric nervous system consists of **parasympathetic postganglionic neuron cell bodies**. These neurons are responsible for coordinating peristalsis and relaxing the internal anal sphincter. In their absence, the affected segment remains in a state of tonic contraction (aperistalsis), leading to functional obstruction and proximal dilation (megacolon). **2. Why Other Options are Incorrect:** * **Options A & C (Preganglionic Neurons):** The cell bodies for preganglionic neurons are located in the Central Nervous System (spinal cord/brainstem), not within the walls of the gastrointestinal tract. * **Option B (Sympathetic Postganglionic Neurons):** These cell bodies are located in the prevertebral ganglia (e.g., superior/inferior mesenteric ganglia) outside the bowel wall. While sympathetic fibers are present in the colon, their absence is not the cause of Hirschsprung disease. **3. NEET-PG High-Yield Clinical Pearls:** * **Gold Standard Diagnosis:** Rectal Suction Biopsy (shows absence of ganglion cells and presence of hypertrophied nerve bundles). * **Histochemistry:** Increased **Acetylcholinesterase (AChE)** activity is a key diagnostic marker. * **Clinical Presentation:** Delayed passage of meconium (>48 hours), "blast sign" (explosive release of gas/stool on digital rectal exam). * **Associated Condition:** Strongly associated with **Down Syndrome** (Trisomy 21) and mutations in the **RET proto-oncogene**. * **Site:** Most commonly involves the **rectosigmoid** region (Short-segment disease).

Q: A 6-month-old baby presents with a history of bloody diarrhea for 2 days and abdominal distension. On examination, the baby screams. What is the most likely diagnosis?

Intussusception. ### Explanation **Correct Answer: A. Intussusception** Intussusception is the most common cause of intestinal obstruction in infants aged 6 to 36 months. It occurs when one segment of the intestine (the intussusceptum) telescopes into an adjacent segment (the intussuscipiens). The classic clinical triad includes **intermittent colicky abdominal pain** (causing the baby to scream and draw up their legs), a **palpable sausage-shaped mass**, and **"red currant jelly" stools** (bloody diarrhea mixed with mucus). Abdominal distension and vomiting are late signs of obstruction. In this case, the combination of age, screaming (pain), and bloody diarrhea strongly points to this diagnosis. **Why other options are incorrect:** * **B. Hemolytic Uremic Syndrome (HUS):** While HUS presents with bloody diarrhea (usually post-*E. coli* O157:H7), it is characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. It typically lacks the acute screaming episodes associated with mechanical obstruction. * **C. Appendicitis:** Rare in infants under 2 years. It usually presents with fever and localized tenderness rather than gross bloody diarrhea. * **D. Acute Enterocolitis:** While it causes bloody diarrhea and distension, the "screaming" episodes (paroxysmal colicky pain) are more characteristic of the mechanical "telescoping" seen in intussusception. **NEET-PG High-Yield Pearls:** * **Most common site:** Ileocolic. * **Lead point:** Usually idiopathic in infants (hypertrophied Peyer’s patches post-viral infection); in older children, consider Meckel’s diverticulum. * **Investigation of Choice (IOC):** Ultrasonography (shows the **"Target" or "Donut" sign**). * **Gold Standard Treatment:** Non-operative reduction using **Air or Hydrostatic Enema**. Surgery is indicated if there are signs of peritonitis or perforation.

Q: A 12-year-old boy presented with abdominal pain. What is the most likely diagnosis?

Peutz-Jeghers syndrome. ***Peutz-Jeghers syndrome*** - **Hamartomatous polyps** in the gastrointestinal tract commonly cause **intussusception** and abdominal pain in children, making this the most likely diagnosis. - Characterized by **perioral melanotic pigmentation** (dark spots around the lips and mouth) which is pathognomonic for this condition. *Cowden syndrome* - Primarily presents with **multiple hamartomas** affecting skin, thyroid, breast, and endometrium, not typically causing abdominal pain in children. - Associated with **PTEN gene mutations** and increased risk of **breast and thyroid cancers** in adulthood. *Cronkhite-Canada syndrome* - A **non-hereditary** polyposis syndrome that typically affects **adults over 50 years**, making it unlikely in a 12-year-old. - Characterized by **alopecia**, **nail dystrophy**, and **hyperpigmentation** along with GI polyps. *Osler-Weber-Rendu syndrome* - Also known as **hereditary hemorrhagic telangiectasia (HHT)**, primarily causes **recurrent nosebleeds** and **telangiectasias**. - Does not typically present with **abdominal pain** as the primary symptom in children.

Q: What are the differential diagnoses for a left-sided abdominal mass in a baby?

All of the above. In pediatric clinical practice, a left-sided abdominal mass requires a systematic anatomical approach, categorizing potential masses by the organ of origin within the left upper and lower quadrants. **Explanation of the Correct Answer:** The correct answer is **D (All of the above)** because the left side of the abdomen contains several structures that can present as a palpable mass due to hypertrophy, malignancy, or obstruction: 1. **Spleen:** Splenomegaly is a common cause of a left-sided mass. In infants, this can be due to hemolytic anemias, infections (TORCH), or portal hypertension. A splenic mass typically moves with respiration and has a palpable notch. 2. **Left Kidney:** Renal masses are the most common cause of neonatal abdominal masses. Differential diagnoses include hydronephrosis, multicystic dysplastic kidney (MCDK), or nephroblastoma (Wilms tumor) in older infants. Renal masses are typically felt deep in the loin and are "ballottable." 3. **Splenic Flexure:** This part of the large intestine can present as a mass if there is significant fecal impaction (common in Hirschsprung disease) or, rarely, intussusception. **Why other options are considered:** Options A, B, and C are all anatomically located in the left hemi-abdomen. Therefore, selecting only one would be incomplete. **High-Yield Clinical Pearls for NEET-PG:** * **Most common neonatal abdominal mass:** Renal in origin (50%), specifically Hydronephrosis. * **Wilms Tumor (Nephroblastoma):** The most common primary renal tumor of childhood; usually presents as a smooth, firm, flank mass that **does not** cross the midline. * **Neuroblastoma:** Often presents as an irregular, firm mass that **does** cross the midline (displacing the kidney inferiorly). * **Physical Exam Tip:** If a mass moves with respiration, think Spleen or Liver; if it is fixed and ballottable, think Kidney.

Q: Which of the following is NOT true about Intussusception?

Ultrasound is of no use in diagnosis.. **Explanation:** Intussusception is the most common cause of intestinal obstruction in infants. The correct answer is **D** because **Ultrasound is actually the gold standard (investigation of choice)** for diagnosis. It has a sensitivity and specificity of nearly 100% in experienced hands, typically showing the classic **"Target" or "Doughnut" sign** in transverse views and the **"Pseudokidney" sign** in longitudinal views. **Analysis of other options:** * **Option A:** It is true that males are more commonly affected than females (ratio approx. 3:1). * **Option B:** This is a slightly controversial point in the question stem, as the peak incidence is typically **5–9 months** of age. However, it can occur in the neonatal period or later. In the context of this MCQ, Option D is "more" false, making it the definitive answer. * **Option C:** On a plain X-ray, the absence of gas in the right lower quadrant (Dance’s sign) and gastric dilation due to proximal obstruction are recognized radiological features. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Intermittent abdominal pain (colicky), "currant jelly" stools, and a palpable sausage-shaped mass in the right upper quadrant. * **Lead Points:** Most cases are idiopathic (linked to lymphoid hyperplasia/Peyer's patches post-viral infection). In children >2 years, look for a pathological lead point like **Meckel’s Diverticulum** (most common), polyps, or HSP. * **Management:** Non-operative reduction using **Air or Hydrostatic (Barium/Saline) enema** is the treatment of choice if there are no signs of perforation or peritonitis.

Q: Which of the following is the most sensitive indicator of intravascular volume depletion in an infant presented with acute rotavirus gastroenteritis?

Heart rate. **Explanation:** In infants and young children, the **heart rate** is the most sensitive and earliest clinical indicator of intravascular volume depletion (dehydration). **1. Why Heart Rate is Correct:** The pediatric cardiovascular system is characterized by a relatively non-compliant left ventricle and a fixed stroke volume. Unlike adults, infants cannot significantly increase their stroke volume to compensate for fluid loss. Therefore, to maintain **Cardiac Output (CO = Heart Rate × Stroke Volume)** during hypovolemia, the infant’s body relies almost exclusively on increasing the heart rate (tachycardia). Tachycardia often precedes other signs like hypotension, which is a late and ominous sign of shock in children. **2. Why Other Options are Incorrect:** * **Cardiac Output:** This is a calculated parameter (HR × SV). While it eventually falls in severe dehydration, it is maintained initially by compensatory tachycardia, making it less sensitive than the heart rate itself. * **Stroke Volume:** In infants, the stroke volume is relatively fixed due to limited ventricular compliance. It decreases as preload drops, but it is not a "sensitive indicator" that can be easily measured or used clinically to detect early depletion. * **Preload:** While intravascular volume depletion directly reduces preload, it is a hemodynamic state rather than a clinical "indicator" easily assessed at the bedside in an emergency setting. **Clinical Pearls for NEET-PG:** * **Earliest Sign of Dehydration:** Tachycardia. * **Most Reliable Sign of Dehydration:** Prolonged capillary refill time (CRT), abnormal skin turgor, and abnormal breathing patterns. * **Late Sign of Dehydration:** Hypotension (indicates uncompensated shock). * **Best Objective Indicator of Dehydration Severity:** Percentage of body weight loss.

Q: In necrotizing enterocolitis, what is the earliest change seen on X-ray abdomen?

Non-specific bowel dilatation. **Explanation:** Necrotizing Enterocolitis (NEC) is the most common gastrointestinal emergency in neonates, particularly preterm infants. Understanding the radiological progression is crucial for early diagnosis and management. **1. Why "Non-specific bowel dilatation" is correct:** The earliest radiological sign of NEC is **generalized, non-specific bowel dilatation** (ileus). This occurs due to intestinal ischemia and dysmotility, leading to gas accumulation before structural damage like intramural air or perforation becomes visible. It is often described as "fixed" or "persistent" loops on serial X-rays. **2. Why the other options are incorrect:** * **B. Gas in the intestinal wall (Pneumatosis intestinalis):** This is the **pathognomonic** (most characteristic) sign of NEC, but it is a later finding than simple dilatation. It indicates that gas-producing bacteria have invaded the bowel wall. * **C. Gas in the splenic flexure:** This is not a specific diagnostic feature of NEC. While gas distribution can vary, localized gas in the splenic flexure is more commonly associated with Hirschsprung disease (cutoff sign). * **D. Ground glass appearance:** This typically suggests **ascites** (peritoneal fluid) or can be seen in Meconium Ileus. In NEC, it may indicate bowel wall edema or perforation with fluid leak, but it is not the earliest sign. **Clinical Pearls for NEET-PG:** * **Pathognomonic Sign:** Pneumatosis intestinalis (linear or cystic lucencies in the bowel wall). * **Sign of Perforation:** Pneumoperitoneum (Football sign, Rigler’s sign, or air under the diaphragm). * **Sign of Advanced Disease:** Portal venous gas (indicates severe necrosis). * **Bell’s Staging:** Used to classify NEC severity based on clinical and radiological findings. * **Most common site:** Terminal ileum and proximal colon.

Question 1

An 8-year-old child is referred with a history of mononeuritis multiplex and hepatosplenomegaly. Examination of the oral cavity and pharynx revealed enlarged orange-colored tonsils. Which of the following statements regarding this condition is false?

Accepted Answer

It is an autosomal recessive condition.

Answer

It is a case of Tangier disease.

Answer

The plasma LDL-c levels will be low.

Answer

It is caused by ABCA1 deficiency.

Question 2

A 23-year-old woman, G2, P1, gave birth at term to a boy of normal weight and length following an uncomplicated pregnancy. The infant initially did well, but at 6 weeks, he began feeding poorly for 1 week, and his mother noticed that much of the milk he ingested was forcefully vomited within 1 hour. Now, on physical examination, the infant is afebrile, and there are no external anomalies. A midabdominal mass is palpable. Bowel sounds are active. The medical history indicates that both the mother and her first child had the same illness during infancy. Which of the following conditions is most likely to explain these findings?

Accepted Answer

Pyloric stenosis

Answer

Annular pancreas

Answer

Diaphragmatic hernia

Answer

Duodenal atresia

Question 3

A 6-year-old girl presents with constipation, abdominal distention, and vomiting. She is diagnosed with Hirschsprung disease (aganglionic megacolon), a congenital condition leading to colon dilation. This condition is caused by the absence of which of the following kinds of neural cell bodies?

Accepted Answer

Parasympathetic postganglionic neuron cell bodies

Answer

Sympathetic preganglionic neuron cell bodies

Answer

Sympathetic postganglionic neuron cell bodies

Answer

Parasympathetic preganglionic neuron cell bodies

Question 4

A 6-month-old baby presents with a history of bloody diarrhea for 2 days and abdominal distension. On examination, the baby screams. What is the most likely diagnosis?

Accepted Answer

Intussusception

Answer

Hemolytic Uremic Syndrome (HUS)

Answer

Appendicitis

Answer

Acute Enterocolitis

Question 5

A 12-year-old boy presented with abdominal pain. What is the most likely diagnosis?

Accepted Answer

Peutz-Jeghers syndrome

Answer

Cowden syndrome

Answer

Cronkhite-Canada syndrome

Answer

Osler-Weber-Rendu syndrome

Question 6

What are the differential diagnoses for a left-sided abdominal mass in a baby?

Accepted Answer

All of the above

Answer

Splenic flexure

Answer

Spleen

Answer

Left kidney

Question 7

Which of the following is NOT true about Intussusception?

Accepted Answer

Ultrasound is of no use in diagnosis.

Answer

Males are commonly affected.

Answer

It commonly presents between 3-8 weeks of age.

Answer

X-ray may show gastric dilation and gasless small intestines.

Question 8

Which of the following is the most sensitive indicator of intravascular volume depletion in an infant presented with acute rotavirus gastroenteritis?

Accepted Answer

Heart rate

Answer

Cardiac output

Answer

Stroke volume

Answer

Preload

Question 9

Reye's syndrome is characterized by which of the following findings?

Accepted Answer

Viral infection is seen

Answer

Presents as deep jaundice

Answer

Cerebral edema

Answer

Microvesicular fatty infiltration

Question 10

In necrotizing enterocolitis, what is the earliest change seen on X-ray abdomen?

Accepted Answer

Non-specific bowel dilatation

Answer

Gas in the intestinal wall

Answer

Gas in the splenic flexure

Answer

Ground glass appearance

Gastroenterology — MCQs

Gastroenterology — MCQs

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