# Hirschsprung Disease > Hirschsprung disease for NEET-PG Paediatrics: delayed meconium, rectal biopsy diagnosis, enterocolitis risk and pull-through surgery. - Canonical URL: https://prepelephant.com/topics/neet-pg/paediatrics/hirschsprung-disease - Exam / course: NEET-PG · Subject: Paediatrics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Hirschsprung Disease", PrepElephant, https://prepelephant.com/topics/neet-pg/paediatrics/hirschsprung-disease ## Direct answer Hirschsprung disease is congenital aganglionosis of the distal bowel — neural crest cells failed to migrate into the rectum and a variable length of colon — producing functional obstruction: the aganglionic segment cannot relax, so stool cannot pass. The neonatal clues are delayed passage of meconium beyond 48 hours in a term baby, abdominal distension and bilious vomiting; the older child has severe constipation from birth with a scaphoid empty rectum on examination and, tellingly, no soiling. Diagnosis is confirmed by rectal suction biopsy showing absent ganglion cells, and the feared complication is Hirschsprung-associated enterocolitis, which remains the major cause of death. ## What you must remember - A term newborn should pass meconium within 24 hours in about 90 per cent of cases and virtually all by 48 hours — delay beyond 48 hours is the single best neonatal clue. - Male-to-female ratio about 4:1; rectosigmoid (short-segment) disease accounts for roughly 75–80 per cent of cases. - Associations: Down syndrome in roughly 5–10 per cent, RET and GDNF gene mutations, and Waardenburg with other neurocristopathies. - Classic examination sign: on digital rectal examination the rectum is empty and stenosed-feeling, followed by explosive discharge of gas and stool on withdrawal — the "squirt sign". - Contrast enema: transition zone between dilated proximal and narrow distal bowel, decreased rectosigmoid index, retained barium at 24 hours. - Anorectal manometry shows absent rectoanal inhibitory reflex — a useful screening test in older children, but rectal biopsy remains the standard. - Diagnostic gold standard: rectal suction biopsy at 1–2 cm (and 3–4 cm) above the dentate line showing absent ganglion cells in the submucosal plexus, hypertrophied nerve trunks and increased acetylcholinesterase activity. - Hirschsprung-associated enterocolitis: fever, explosive foul diarrhoea, abdominal distension and sepsis, due to stasis and bacterial overgrowth; it can occur before or after surgery — treat with rectal decompression, broad-spectrum antibiotics and resuscitation. - Definitive surgery: pull-through procedures (Swenson, Duhamel, Soave — transanal endorectal pull-through is now common), increasingly as single-stage procedures in the neonatal period; a diverting colostomy precedes pull-through in complicated or late-presenting cases. - Distinguish from functional constipation: Hirschsprung starts from birth, has no soiling, empty rectum and failure to thrive; functional constipation has intermittency, overflow soiling and stool palpable in the rectum. ## A typical exam case A two-day-old term boy has not passed meconium at 52 hours and now has gross abdominal distension with bilious vomiting. Pass a warm rectal examination: tight lower rectum, then a gush of gas and meconium on withdrawal — relief that is temporary and diagnostic in direction. Plain radiograph shows dilated loops; resuscitate, decompress with rectal irrigation, and obtain a contrast enema demonstrating the transition zone. Confirmation is by rectal suction biopsy: no ganglion cells, hypertrophied nerve trunks. Plan a pull-through — many centres now do a primary transanal endorectal pull-through in the stable neonate — counselling that enterocolitis remains possible even after successful surgery. The second presentation earns its own question: a three-year-old with abdominal distension, chronic constipation since the neonatal period, ribbon-like stools, poor growth and never any soiling, in whom abdominal examination finds distension but the rectum is strikingly empty. That constellation — constipation from birth plus empty rectum plus no soiling — should make you request anorectal manometry and biopsy rather than prescribing another laxative. And the emergency stem: a known Hirschsprung baby returns with fever, explosive diarrhoea and a distended, tender abdomen — enterocolitis, needing fluids, broad-spectrum antibiotics, decompression, gentle rectal irrigation and urgent surgical review, because perforation and toxic megacolon kill. ## Where students slip The recurring errors are shortcut errors. First, treating barium enema or the transition zone as diagnostic — radiology suggests, but only biopsy proves, and a transition zone may be absent in long-segment disease or misleading in enterocolitis. Second, forgetting the biopsy level: sampling too low or too high gives false negatives because of the normal hypoganglionic zone within a centimetre of the dentate line. Third, missing soiling logic in the older child — functional constipation produces overflow soiling while Hirschsprung does not, and inverting that relationship costs the mark. And candidates who counsel "surgery cures everything" forget post-pull-through enterocolitis and persistent constipation, which dominate follow-up questions in viva. ## Frequently asked questions ### Which finding in a term newborn most strongly suggests Hirschsprung disease? Failure to pass meconium within 48 hours of birth — the vast majority of term infants pass meconium in the first day, so delay demands evaluation alongside distension and vomiting. ### What is the confirmatory diagnostic test? Rectal suction biopsy showing absent submucosal ganglion cells with hypertrophied nerve trunks and increased acetylcholinesterase staining, taken 1–2 cm above the dentate line. ### How does Hirschsprung-associated enterocolitis present? With fever, abdominal distension and explosive, often bloody diarrhoea due to stasis and bacterial overgrowth; it is the leading cause of death, may precede or follow surgery, and needs antibiotics with rectal decompression. ### Which type of Hirschsprung disease is most common? Short-segment disease confined to the rectosigmoid in about three-quarters of cases, with a male predominance of about 4:1.