Gastroenterology — MCQs

A 5-year-old girl is brought to the physician after her parents notice red blood in her stool. Physical examination reveals mucocutaneous pigmentation. Small bowel radiography discloses multiple, small- to medium-sized polyps that are diagnosed pathologically as hamartomas. Which of the following is the most likely diagnosis?

Gastroenterology Indian Medical PG Practice Questions and MCQs

Question 321: A 4-year-old girl weighing 12 kg, with diarrhea, skin pinch that goes back very slowly, and who is unable to drink, is most likely to:

A. Start IV fluids per Plan C (Correct Answer)
B. Discharge home with oral fluids
C. Monitor for worsening dehydration
D. Attempt oral rehydration with ORS

Explanation: ***Start IV fluids per Plan C*** - The child presents with **severe dehydration** based on WHO criteria: **skin pinch goes back very slowly** (>2 seconds) and **unable to drink**. - These two signs mandate immediate **Plan C management** which involves rapid IV fluid resuscitation using **Ringer's Lactate or Normal Saline**. - WHO Plan C protocol: Give **100 ml/kg** IV fluids divided as 30 ml/kg in first hour (if <12 months) or first 30 minutes (if ≥12 months), then 70 ml/kg over next 2.5-5 hours. - Plan C is specifically designed for **severe dehydration** requiring immediate intravenous rehydration, not Plan B which is for moderate dehydration with oral rehydration. *Discharge home with oral fluids* - Discharging a child with **severe dehydration** is inappropriate and potentially life-threatening. - The child **cannot drink** effectively, making home management with oral fluids impossible and dangerous. - This would lead to worsening dehydration, shock, and potentially fatal complications. *Monitor for worsening dehydration* - While monitoring is important, this child requires **immediate active intervention**, not observation alone. - Delaying IV rehydration in a child with **severe dehydration** (unable to drink, very slow skin pinch) could lead to hypovolemic shock, acute kidney injury, and death. *Attempt oral rehydration with ORS* - This child is **unable to drink**, making ORS ineffective and contraindicated. - Oral rehydration (Plan B) is appropriate only for **moderate dehydration** in children who are conscious, alert, and able to drink. - Attempting ORS in a child unable to drink delays appropriate IV therapy and worsens outcomes.

Question 322: What is true regarding congenital hypertrophic pyloric stenosis?

A. Heller's myotomy is the procedure of choice
B. More common in girls
C. Hypochloremic alkalosis (Correct Answer)
D. Most often manifests at birth

Explanation: ***Hypochloremic alkalosis*** - The forceful vomiting in pyloric stenosis leads to a significant loss of **hydrochloric acid** from the stomach, resulting in **metabolic alkalosis**. - Additionally, the loss of gastric fluid containing chloride contributes to **hypochloremia**. *More common in girls* - **Congenital hypertrophic pyloric stenosis** is significantly more common in **boys**, with a male-to-female ratio of about 4:1. - This gender predilection is a key epidemiological feature of the condition. *Heller's myotomy is the procedure of choice* - **Ramstedt pyloromyotomy** is the standard surgical procedure for pyloric stenosis, involving the incision of the hypertrophied pyloric muscle. - **Heller's myotomy** is a procedure typically performed for **achalasia**, a disorder of the esophagus, not pyloric stenosis. *Most often manifests at birth* - Symptoms of pyloric stenosis usually manifest between **2 and 8 weeks of age**, not immediately at birth. - The hypertrophy of the pyloric muscle takes time to progress sufficiently to cause significant obstruction.

Question 323: A 12 kg child with diarrhoea and some dehydration: based on WHO guidelines, how much fluid should be replaced in the first 4 hours?

A. 0-400 ml
B. 400-800 ml
C. 800-1200 ml (Correct Answer)
D. 1200-1600 ml

Explanation: ***800-1200 ml*** - For a child weighing **12 kg** with **some dehydration** due to diarrhea, WHO Plan B recommends **75 mL/kg** over 4 hours. - Therefore, 12 kg × 75 mL/kg = **900 mL**, which falls within this range. - This range allows for slight variations in clinical practice while staying close to the WHO standard guideline. *0-400 ml* - This range is significantly **too low** for a 12 kg child with some dehydration, as it would not adequately address the fluid deficit. - Inadequate fluid replacement can lead to worsening dehydration and its associated complications, such as **persistent signs of dehydration or progression to severe dehydration**. *400-800 ml* - While higher than the lowest option, **400-800 mL** is still generally insufficient for a 12 kg child needing rehydration over 4 hours per WHO Plan B. - This amount would only partially correct the fluid deficit, potentially delaying recovery and necessitating further interventions. *1200-1600 ml* - This range is **excessive** for WHO Plan B rehydration in a 12 kg child over 4 hours, potentially leading to **fluid overload**. - While adequate rehydration is crucial, administering significantly more than 75 mL/kg can increase the risk of complications, especially in children with underlying cardiac or renal conditions.

Question 324: The commonest cause of intestinal obstruction and abdominal pain in children between 3 months and 6 years of age is:

A. Intussusception (Correct Answer)
B. Meckel's diverticulum
C. Intestinal polyp
D. Nonspecific cause

Explanation: ***Intussusception*** - **Intussusception** is the most common cause of **intestinal obstruction** in children between 3 months and 6 years of age, with peak incidence at 6-18 months. - It occurs when one segment of the intestine telescopes into an adjacent segment, leading to obstruction and vascular compromise. - Classic presentation includes sudden onset of **colicky abdominal pain** (intermittent, with child drawing knees to chest), vomiting, and "currant jelly" stools (late sign due to mucosal sloughing). - A palpable "sausage-shaped" mass may be felt in the right upper quadrant with emptiness in the right iliac fossa (Dance's sign). *Meckel's diverticulum* - **Meckel's diverticulum** is the most common congenital anomaly of the GI tract (present in ~2% of population) but is not the most common cause of intestinal obstruction in this age group. - It typically presents with **painless rectal bleeding** due to ectopic gastric mucosa causing peptic ulceration. - When it does cause obstruction, it's usually through complications like volvulus, band formation, or serving as a lead point for intussusception, not as a primary direct obstruction. *Intestinal polyp* - **Intestinal polyps** (most commonly juvenile polyps) in children primarily present with **painless rectal bleeding**, not intestinal obstruction. - They can occasionally serve as a lead point for intussusception but are not a common primary cause of obstruction. - They are rare in the infant age group and more common in older children. *Nonspecific cause* - This is not a specific diagnostic entity and would not be an acceptable diagnosis for intestinal obstruction requiring immediate management. - In pediatric practice, identifying a specific cause like **intussusception** is essential for appropriate treatment (air or hydrostatic reduction vs. surgery). - The acute presentation of intestinal obstruction in this age group has well-defined specific causes, with intussusception being the most common.

Question 325: Most common genetic mutation associated with Hirschsprung's disease is:

A. RET gene (Correct Answer)
B. ATP 7A
C. EDNRB gene
D. EDN3 gene

Explanation: ***RET gene*** - Mutations in the **RET proto-oncogene** are the most common genetic cause of Hirschsprung's disease, accounting for up to 50% of familial cases and 15-20% of sporadic cases. - The RET gene codes for a **receptor tyrosine kinase** involved in the development of the enteric nervous system. *EDN3 gene* - The **EDN3 gene** (endothelin 3) plays a role in Hirschsprung's disease; however, mutations in this gene are much less common than those in the RET gene. - EDN3 mutations are typically associated with a smaller subset of Hirschsprung's cases. *ATP 7A* - The **ATP7A gene** is associated with **Menkes disease**, a disorder of copper transport, not Hirschsprung's disease. - This gene codes for a copper-transporting ATPase. *EDNRB gene* - The **EDNRB gene** (endothelin receptor type B) is involved in some cases of Hirschsprung's disease, but mutations in this gene are less frequent than RET mutations. - It works in conjunction with EDN3 in neural crest cell development.

Question 326: What are the clinical implications of the persistence of an omphalomesenteric duct?

A. Gastroschisis
B. Omphalocele
C. Ectopia vesicae
D. Meckel's diverticulum (Correct Answer)

Explanation: ***Meckel's diverticulum*** - The **omphalomesenteric duct**, also known as the **vitelline duct**, normally obliterates during fetal development. **Meckel's diverticulum** is the most common congenital abnormality of the small intestine, resulting from the incomplete obliteration of the vitelline duct. - This remnant can contain **heterotopic gastric or pancreatic tissue**, leading to complications like **bleeding**, **obstruction**, or **inflammation (diverticulitis)**. *Gastroschisis* - **Gastroschisis** is a birth defect where the intestines and other abdominal organs protrude *outside* the body through a hole next to the naval, *without* a covering membrane. - This condition is not directly caused by the persistence of the omphalomesenteric duct; it's a defect in the **anterior abdominal wall closure**. *Omphalocele* - **Omphalocele** is a birth defect in which the intestines and other abdominal organs protrude *into* the umbilical cord and are covered by a membrane. - This condition also results from a failure of abdominal wall closure during development and is distinct from abnormalities of the omphalomesenteric duct. *Ectopia vesicae* - **Ectopia vesicae**, or **bladder exstrophy**, is a rare birth defect where the bladder is exposed *outside* the body through a defect in the abdominal wall and bladder closure. - This defect is related to a developmental failure of the infraumbilical abdominal wall and the anterior bladder wall, entirely separate from the omphalomesenteric duct.

Question 327: A newborn child who has not passed meconium for 48 hours. What is the diagnostic procedure of choice?

A. USG
B. Contrast enema (Correct Answer)
C. CT
D. MRI

Explanation: **Contrast enema** - A **contrast enema** is the diagnostic procedure of choice to visualize the colon and rectum, evaluate for a **transition zone**, and identify potential causes of **meconium retention**, such as **Hirschsprung disease** or **meconium plug syndrome**. - It can differentiate between various causes of neonatal intestinal obstruction by showing the caliber of the bowel lumen and the presence of any filling defects. *USG* - **Ultrasound** (USG) is generally not the primary diagnostic tool for evaluating delayed meconium passage as it provides limited information about the detailed anatomy and function of the intestinal lumen necessary for diagnosing conditions like **Hirschsprung disease**. - While it can detect some abdominal abnormalities, it is less effective for defining the specific causes of distal intestinal obstruction in this context. *CT* - **Computed Tomography (CT)** scans expose the neonate to significant **ionizing radiation**, and its use is typically reserved for more complex cases or when other less invasive methods have been inconclusive. - While CT can provide detailed anatomical images, it is not the initial or preferred diagnostic procedure for evaluating delayed meconium passage due to the radiation risk and the effectiveness of **contrast enema**. *MRI* - **Magnetic Resonance Imaging** (MRI) also involves prolonged imaging times and may require sedation in neonates, making it less practical as a first-line diagnostic modality for delayed meconium passage. - Although it provides excellent soft tissue contrast, its role in diagnosing intestinal obstructions in newborns is limited, especially given the rapid and effective diagnostic capabilities of a **contrast enema**.

Question 328: What is the calculated fluid requirement for treating dehydration and maintenance over a 4-hour period in a 14 kg, 14-month-old child with a 4-day history of loose stools, decreased urine output, delayed skin pinch, sunken eyes, and dry mucosa?

A. 1050 ml (Correct Answer)
B. 700 ml
C. 1200 ml
D. 2000 ml

Explanation: ***1050 ml*** - This calculation includes **dehydration correction** (70-75 ml/kg for severe dehydration over 4 hours: 14 kg × 75 ml/kg = 1050 ml) and **maintenance fluid** (14 kg requires 50 ml/hour by Holiday-Segar: 50 ml/hr × 4 hours = 200 ml), but in **severe dehydration**, the initial rapid rehydration phase prioritizes deficit correction. - The child exhibits signs of **severe dehydration** (decreased urine output, delayed skin pinch, sunken eyes, dry mucosa), indicating 7-10% fluid loss requiring **Plan C (IV rehydration)** per WHO/IAP guidelines. - **Standard protocol:** 100 ml/kg total over 6 hours (30 ml/kg in first 1 hour, then 70 ml/kg over next 5 hours). For a 4-hour calculation, approximately 75 ml/kg (1050 ml) addresses the urgent deficit while allowing gradual correction. *1200 ml* - This represents the full calculated amount including both **deficit replacement** and **maintenance fluid** (1050 ml + 200 ml ≈ 1250 ml). - While mathematically close, administering this volume over only 4 hours might be **too rapid** for a severely dehydrated child, increasing risk of complications. - The question specifically asks for 4-hour management, where **deficit correction takes priority** over full maintenance addition. *700 ml* - This volume represents only **50 ml/kg**, which is significantly **insufficient** for severe dehydration (requires 100 ml/kg total). - Would be appropriate for **moderate dehydration** (5-7% deficit) but inadequate for this child's clinical presentation. - Administering only 700 ml would lead to **persistent dehydration** and worsening clinical status. *2000 ml* - This amount (143 ml/kg) would result in **gross overhydration**, potentially causing life-threatening complications like **pulmonary edema**, **cerebral edema**, or **heart failure**. - Exceeds the standard 100 ml/kg deficit by nearly 50%, with excessive volume administered too rapidly. - Represents dangerous **fluid overload** for a 14 kg child with severe dehydration.

Question 329: Aganglionic segment is encountered in which part of the colon in case of Hirschsprung's disease?

A. Distal to dilated segment (Correct Answer)
B. In whole colon
C. Proximal to dilated segment
D. In dilated segment

Explanation: ***Distal to dilated segment*** - In **Hirschsprung's disease**, the aganglionic (lacking nerve ganglia) segment is always located **distal to the dilated segment**. - The dilated segment occurs because stool accumulates *proximal* to the constricted aganglionic portion, which cannot relax to allow passage. - The aganglionic segment is typically in the **rectosigmoid region** (80% of cases), though it can extend more proximally. *In whole colon* - Total colonic aganglionosis is a very rare form of Hirschsprung's disease (~5% of cases), but it's not the typical presentation where a specific segment is affected. - The classic presentation involves a shorter segment of aganglionosis, usually in the rectosigmoid. *Proximal to dilated segment* - The segment *proximal* to the aganglionic zone is typically the normal, ganglionated segment that becomes enlarged due to fecal backup. - The pathology in Hirschsprung's disease is the *absence* of ganglia in the distal segment, not proximal to the obstruction. *In dilated segment* - The dilated segment is **not aganglionic**; it is the normal, ganglionated colon that has hypertrophied and distended due to the obstruction from the distal aganglionic segment. - The problem is *distal* to this dilated, functional (but obstructed) colon.

Question 330: A 5-year-old girl is brought to the physician after her parents notice red blood in her stool. Physical examination reveals mucocutaneous pigmentation. Small bowel radiography discloses multiple, small- to medium-sized polyps that are diagnosed pathologically as hamartomas. Which of the following is the most likely diagnosis?

A. Congenital teratoma
B. Hyperplastic polyp
C. Peutz-Jeghers syndrome (Correct Answer)
D. Tubular adenoma

Explanation: ***Peutz-Jeghers polyp*** - Characterized by **mucocutaneous pigmentation** and **hamartomatous polyps**, aligning perfectly with the clinical findings of this patient [1]. - Commonly causes gastrointestinal bleeding, as suggested by the presence of **red blood in stool**. *Congenital teratoma* - Generally involves **solid masses** and is **not typically associated** with gastrointestinal polyps or pigmentation. - Would present differently, often as a mass in the **abdomen** or pelvis rather than causing blood in the stool. *Tubular adenoma* - These are **neoplastic polyps** that do not present with **pigmentation**, which the patient has. - Typically associated with **malignant potential**, unlike hamartomas seen in this scenario. *Hyperplastic polyp* - Recognized as a **benign lesion**, which does not present with mucocutaneous **pigmentation** or gastrointestinal bleeding. - Lacks the characteristic features of **hamartomas**, making it an unlikely diagnosis in this case. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 813-815.

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