A 1.2 kg neonate born at 30 weeks gestation develops abdominal distension, bloody stools, and X-ray shows pneumatosis intestinalis with portal venous gas on day 8. Which of the following is the MOST likely pathophysiological trigger in this preterm infant?
- A Mesenteric vasospasm due to polycythemia
- B Bacterial colonization of ischemic mucosa in a gut with immature mucosal defense ✓
- C Clostridium difficile toxin-mediated pseudomembranous colitis
- D Congenital Hirschsprung's disease complicated by enterocolitis
Correct answer: B. Bacterial colonization of ischemic mucosa in a gut with immature mucosal defense
Explanation
Necrotizing enterocolitis (NEC) in premature infants results from a triad of mucosal ischemia, bacterial colonization (often Gram-negative organisms), and immature gut immune defenses. The preterm intestine lacks adequate secretory IgA, has deficient mucus barrier function, and is prone to ischemia-reperfusion injury after feeds. Pneumatosis intestinalis represents gas produced by intramural bacteria and is a hallmark radiological finding; portal venous gas indicates advanced disease.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.