Hirschsprung's disease results from failure of craniocaudal migration of neural crest cells. The aganglionic segment always begins at the internal anal sphincter and extends proximally. The classic presentation is constipation from birth and failure to pass meconium in first 48 hours. What is the most accurate diagnostic investigation in a neonate?

• A Barium enema showing transition zone — reliably diagnostic in all neonates
• B Anorectal manometry — absence of rectoanal inhibitory reflex (RAIR)
• C Plain abdominal X-ray showing absence of gas in rectum
• D Suction rectal biopsy — absence of ganglion cells and positive acetylcholinesterase staining ✓

Explanation

Suction rectal biopsy is the gold standard for diagnosing Hirschsprung's disease, showing absence of ganglion cells in the submucosal (Meissner's) plexus and hypertrophied nerve bundles with strong acetylcholinesterase staining. It is performed as an outpatient procedure without general anaesthesia. Anorectal manometry (absent RAIR) is reliable in older children but technically difficult in neonates. Barium enema showing a transition zone is unreliable in neonates in the first few weeks of life because the segment may not have dilated.

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

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Written and medically reviewed by the StethoPrep medical team.