Hirschsprung's Disease

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HD 101 - Gut's Missing Ganglia

  • Congenital aganglionic megacolon causing functional bowel obstruction.
  • Embryology: Defective craniocaudal migration of neural crest cells (NCCs) during weeks 4-12 gestation.
    • NCCs fail to populate distal bowel.
    • RET gene mutations are frequently implicated.
  • Pathophysiology: Absence of ganglion cells (Auerbach's & Meissner's plexuses) in distal segment.
    • Results in a tonically contracted aganglionic segment.
    • Leads to proximal bowel dilatation. Hirschsprung's Disease vs Normal Colon

⭐ The aganglionosis always starts at the anus and extends proximally; rectosigmoid is affected in ~80% of cases.

HD Signs - Blocked Baby Blues

FeatureNeonatesOlder Infants/Children
MeconiumFailure to pass (>24-48h) - cardinal signHistory of delayed passage
VomitingBiliousOccasional, may be non-bilious
AbdomenProgressive distensionChronic distension, palpable fecal masses
StoolsObstipation; explosive on DREChronic constipation, ribbon-like, foul
SystemicEnterocolitis risk (fever, diarrhea)Failure to thrive (FTT), malnourishment

HD Detective - Unmasking Aganglionosis

  • Suspicion: Failure to pass meconium (>24-48h), bilious emesis, abdominal distension, chronic constipation, enterocolitis episodes.
  • Imaging:
    • AXR: Dilated proximal bowel loops, paucity of distal gas.
    • Contrast Enema (Barium/Gastrografin): Transition zone (key!), narrow spastic distal segment, dilated proximal bowel. Retained contrast >24h.
  • Anorectal Manometry: Absence of Rectoanal Inhibitory Reflex (RAIR); useful if enema equivocal or in older children.
  • Gold Standard: Rectal Biopsy
    • Suction biopsy (2-3 cm above dentate line) or full-thickness.
    • Histology: Absence of ganglion cells (submucosal/myenteric plexuses).
    • Key: Hypertrophied nerve trunks (Acetylcholinesterase positive staining).

    ⭐ Gold standard: Full-thickness rectal biopsy showing aganglionosis & hypertrophied, AChE-positive nerve trunks. 📌 HD: Transition Zone, Aganglionic Biopsy. (TZAB)

HD Solutions - Surgical Fixes & Woes

  • Core Principle: Resect aganglionic segment, pull-through healthy bowel to anus.
  • Key Procedures:
    • Swenson: Original pull-through; full-thickness resection.
    • Soave: Endorectal mucosectomy, ganglionated bowel pulled through muscular cuff. (📌 Soave = Submucosal/Stripping)
    • Duhamel: Retrorectal transanal pull-through; side-to-side anastomosis.
    • Minimally Invasive: Laparoscopic or transanal (TEPT).
  • Post-Op Woes:
    • Hirschsprung-Associated Enterocolitis (HAEC):
      • Signs: Fever, distension, explosive foul diarrhea.
      • Rx: Aggressive! IV fluids, antibiotics, rectal irrigations.
    • Anastomotic stricture/leak.
    • Persistent constipation/soiling.

Surgical procedures for Hirschsprung's disease

⭐ HAEC remains the leading cause of morbidity and mortality in HD patients, occurring in up to 20-30% even after corrective surgery.

High‑Yield Points - ⚡ Biggest Takeaways

  • Congenital aganglionosis of the distal bowel, most commonly rectosigmoid.
  • Results from failed neural crest cell migration to the hindgut.
  • Neonates: delayed meconium passage (>24-48 hours), bilious vomiting, abdominal distension.
  • Gold standard diagnosis: Rectal biopsy showing absent ganglion cells.
  • Contrast enema: transition zone between narrowed aganglionic and dilated ganglionic bowel.
  • Anorectal manometry: absent rectoanal inhibitory reflex (RAIR).
  • Treatment: Surgical resection of affected segment; risk of Hirschsprung-Associated Enterocolitis (HAEC).

Practice Questions: Hirschsprung's Disease

Test your understanding with these related questions

A male infant presented with distension of abdomen shortly after birth with delayed passage of meconium. Subsequently a full-thickness biopsy of the rectum was performed. The rectal biopsy is likely to show:

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Flashcards: Hirschsprung's Disease

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Congenital hydroceles are treated by _____.

TAP TO REVEAL ANSWER

Congenital hydroceles are treated by _____.

herniotomy

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