Hirschsprung's Disease

Pathophysiology

• Congenital absence of ganglion cells in the Meissner and Auerbach plexuses leading to failure of bowel relaxation

• Results in functional bowel obstruction with spastic contraction of the aganglionic segment and proximal dilatation

• Can be classified as short-segment or long-segment disease based on extent of involvement

• Associated with abnormal neural crest cell migration during embryogenesis

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Presentation

• Neonatal

  • Failure to pass meconium within 48 hours in 90–99% of cases

  • Abdominal distension and bilious vomiting

  • "Squirt sign": Explosive passage of stool and gas on digital rectal examination

• Infants and Children

  • Chronic constipation with history of failure to thrive

  • Ribbon-like or pebble-like stools

  • Recurrent episodes of enterocolitis, which may present with fever and diarrhoea

  • Persistent abdominal distension

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Examination

• Abdominal distension often noted on visual inspection

• Digital rectal examination reveals a tight anal sphincter and a narrow or empty rectum

• Explosive release of stool and gas upon withdrawal of the finger is pathognomonic

• Assess for signs of dehydration or sepsis, especially if enterocolitis is suspected

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Diagnosis

• Imaging

  • Plain abdominal X-ray shows dilated loops of bowel with absence of rectal gas

  • Contrast enema reveals a transition zone between a dilated proximal bowel and narrowed distal segment

• Confirmatory Test

  • Rectal biopsy demonstrating absence of ganglion cells and hypertrophied nerve fibres

• Ancillary Testing

  • Anorectal manometry may show failure of internal anal sphincter relaxation

  • Screen for associated anomalies, particularly cardiac or genetic

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Treatment

• Definitive Management

  • Surgical resection of the aganglionic segment followed by a pull-through procedure

• Pre-operative Management

  • Bowel decompression via rectal irrigation or stoma creation if enterocolitis is present

  • Management of enterocolitis with appropriate antibiotics and fluid resuscitation

• Postoperative Care

  • Monitor for complications such as anastomotic leak, recurrence of enterocolitis, and chronic constipation

  • Long-term follow-up to assess continence, nutritional status, and growth

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Notes

• Enterocolitis occurs in approximately 30% of cases and can be life-threatening

• There is a strong genetic link, especially in patients with Down syndrome

• Early diagnosis and intervention are crucial to prevent long-term complications such as chronic kidney disease and growth delays

• Regular follow-up is essential to monitor for persistent constipation or incontinence after surgery