Hirschsprung's disease (congenital aganglionic megacolon) presents as failure to pass meconium in the first 48 hours of life. What is the pathophysiological basis?
- A Hypertrophy of the myenteric plexus causing functional obstruction
- B Abnormal smooth muscle development in the internal anal sphincter
- C Absence of ganglion cells in the Meissner's and Auerbach's plexuses in a segment of colon due to failure of neural crest cell migration ✓
- D Colonic atresia due to in utero vascular accident
Correct answer: C. Absence of ganglion cells in the Meissner's and Auerbach's plexuses in a segment of colon due to failure of neural crest cell migration
Explanation
Hirschsprung's disease results from failure of craniocaudal migration of neural crest cells into the hindgut, leaving a segment of colon aganglionic (absent Meissner's submucosal and Auerbach's myenteric plexuses). The aganglionic segment fails to relax and acts as a functional obstruction. In 80% of cases the rectosigmoid is affected. Diagnosis is by rectal suction biopsy showing absence of ganglion cells and increased acetylcholinesterase staining. Treatment is pull-through surgery (Swenson, Duhamel, or Soave procedures). RET proto-oncogene mutations are implicated.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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