A 2-day-old neonate has failed to pass meconium and has a distended abdomen. Contrast enema shows a transition zone in the sigmoid colon. Rectal suction biopsy confirms absence of ganglion cells with increased acetylcholinesterase staining. This is consistent with Hirschsprung's disease. The level of aganglionosis determines surgery. What is the most common level affected?
- A Rectosigmoid junction (short segment — most common, 80%) ✓
- B Entire colon (total colonic Hirschsprung's)
- C Mid-sigmoid colon
- D Ileocaecal junction (long segment)
Correct answer: A. Rectosigmoid junction (short segment — most common, 80%)
Explanation
Hirschsprung's disease involves aganglionosis that always begins at the internal anal sphincter and extends proximally. The rectosigmoid junction is affected in 80% of cases (short-segment type). Long-segment disease (extending proximal to sigmoid) accounts for 15%, and total colonic aganglionosis for about 5%. Definitive surgery (Swenson, Soave, or Duhamel pull-through) removes the aganglionic segment.
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.