A newborn presents with failure to pass meconium within 48 hours, abdominal distension, and bilious vomiting. A suction rectal biopsy confirms absence of ganglion cells in the submucosal and myenteric plexuses. Which imaging finding on contrast enema is pathognomonic?
- A Transition zone with dilated proximal colon and narrow distal aganglionic segment ✓
- B Microcolon throughout
- C Apple core lesion in the sigmoid colon
- D Bird's beak appearance at the rectum
Correct answer: A. Transition zone with dilated proximal colon and narrow distal aganglionic segment
Explanation
Hirschsprung's disease shows a characteristic transition zone on contrast enema where the narrow, aganglionic distal segment meets the dilated, normally innervated proximal bowel; this transition zone is pathognomonic. The ratio of rectal diameter to sigmoid diameter >1 on 24-hour delayed film (retained contrast) is another diagnostic clue. Definitive diagnosis requires suction rectal biopsy.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.