A 2-day-old neonate has failed to pass meconium and develops bilious vomiting and abdominal distension. Abdominal X-ray shows dilated bowel loops and 'ground glass' appearance in the right iliac fossa. Gastrografin enema reveals a microcolon and pellets of inspissated meconium in the terminal ileum. The diagnosis is meconium ileus. The condition most closely associated with meconium ileus is:

• A Cystic fibrosis (CFTR mutation) ✓
• B Hirschsprung's disease
• C Pancreatic duct atresia
• D Total colonic aganglionosis

Explanation

Meconium ileus is caused by abnormally thick, inspissated meconium due to absent pancreatic enzyme secretion and abnormal mucous in the terminal ileum. Approximately 90-95% of meconium ileus cases are associated with cystic fibrosis (CF, CFTR gene mutations on chromosome 7), and meconium ileus occurs in 10-15% of CF neonates. Meconium ileus may be the presenting manifestation of CF. Gastrografin enema is both diagnostic and therapeutic (hyperosmolar contrast draws fluid into the bowel lumen, loosening the meconium). Failure of enema treatment requires surgical enterostomy and washout. CF genotyping and sweat chloride testing confirm the diagnosis.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.