Surgery MCQs Q40

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PEDIATRIC SURGERY • OBSTRUCTION

A 6-week-old premature infant presents with abdominal distension, irritability, and vomiting. Groin examination was initially overlooked. An abdominal X-ray reveals gas in the scrotum.

What is the most likely diagnosis?

A Intussusception

B Necrotizing enterocolitis

C Incarcerated inguinal hernia

D Volvulus

E Ileal atresia

The correct answer is Incarcerated inguinal hernia.

Decoding the Stem

1

CLUE "Infant + distension + gas in scrotum"

TRANSLATION Communication via patent processus vaginalis with herniated bowel.

Detailed Explanation

✅ Correct Option (Incarcerated Inguinal Hernia): This is a common and critical condition in premature infants. Unlike adults, pediatric inguinal hernias are almost exclusively indirect, occurring due to the failure of the processus vaginalis to close after testicular descent.

Pathophysiology and Clues:

→ Gas in the Scrotum: This is a pathognomonic radiological finding. It indicates that air-filled bowel loops have descended into the scrotal sac through the patent processus vaginalis.

→ Incarceration: When the herniated bowel becomes trapped, it leads to a closed-loop obstruction, causing abdominal distension, vomiting, and irritability.

→ Clinical Trap: Pediatric hernias are often missed because the "bulge" may be intermittent or hidden by the diaper; hence the classic surgical teaching: "Always check the groins in any child with abdominal pain or vomiting."

❌ Why other options are incorrect:

→ Necrotizing enterocolitis: While common in prematures, the X-ray finding would be pneumatosis intestinalis (gas in bowel wall) or pneumoperitoneum, not scrotal gas.

→ Intussusception: Typically presents in slightly older infants (6–18 months) with "currant jelly" stools and colicky pain; no scrotal involvement.

→ Volvulus: A midgut volvulus presents with sudden onset bilious vomiting; the X-ray usually shows a "corkscrew" appearance or gasless abdomen.

→ Ileal atresia: A congenital cause of neonatal obstruction, but it presents within the first 24–48 hours of life, not at 6 weeks.

🧠 High-Yield Pearls

✔ Gas in scrotum = Inguinal hernia until proven otherwise.

✔ Examination: Never forget to examine the groins in pediatric abdominal cases.

✔ Urgency: If irreducible (incarcerated), it requires urgent reduction/surgery to prevent strangulation.

Integrated Clinical Questions

1. Cause of pediatric inguinal hernia?

→ Patent processus vaginalis.

2. Most common type in children?

→ Indirect inguinal hernia.

3. Why more common in premature babies?

→ Incomplete closure of the processus vaginalis (it normally closes in late gestation).

4. Complication if untreated?

→ Strangulation leading to bowel ischemia and necrosis.

5. Definitive treatment?

→ Urgent surgical repair (Herniotomy).

⚡ Exam Pearls

• • Gas in scrotum = Diagnostic clue for inguinal hernia in infants.
• • Premature baby + bowel obstruction symptoms = Think hernia first.
• • Frequently tested concept in pediatric surgery exams.

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