What is Hirschsprung Disease?
Hirschsprung disease is a congenital disorder characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the distal bowel, resulting in functional intestinal obstruction. 1, 2
Pathophysiology
- The disease results from failure of neural crest cells to migrate and populate the distal bowel during gestation, leading to an aganglionic segment that cannot relax and causes functional obstruction 3
- The aganglionic segment typically starts in the distal rectum and can extend proximally to involve varying lengths of colon or even the entire gastrointestinal tract 1
- Histopathologically, Hirschsprung disease is classified as a primary congenital/familial neuropathy affecting the enteric nervous system, with predominant involvement of the myenteric plexus 1
Clinical Presentation
Neonatal Period
- Most commonly presents within the first 2 days of life with bilious vomiting and distal bowel obstruction 1
- Radiographs typically show multiple distended bowel loops with absent or decreased distal gas, requiring contrast enema to differentiate from other causes of distal obstruction like ileal atresia or meconium ileus 1
- Failure to pass meconium within 48 hours is a classic presenting sign 1
Beyond Infancy
- Can present at any age with chronic constipation, though frequency decreases with age 1
- Rare variant forms exist, including hypoganglionosis isolated to the anorectal canal, which can present in adulthood 4
Diagnostic Approach
- Diagnosis requires histologic confirmation demonstrating absence of ganglion cells in rectal biopsies from both submucosal and myenteric plexuses 2, 5
- Contrast enema is the primary imaging modality for suspected distal obstruction in neonates, showing a transition zone between dilated proximal bowel and narrowed aganglionic distal segment 1
- The location of biopsy (rectum vs more proximal) is essential for accurate interpretation 1
Associated Conditions
- Congenital central hypoventilation syndrome (CCHS) is an important associated condition that should be documented when present 6
- Malrotation occurs in approximately 28% of cases with duodenal atresia, requiring upper GI series for diagnosis 7
Complications
Hirschsprung-Associated Enterocolitis (HAEC)
- HAEC is a life-threatening inflammatory complication that can occur pre- or postoperatively, associated with increased morbidity and mortality 3
- The pathogenesis involves intestinal dysmotility, dysbiosis, and impaired mucosal barrier function 3
- Diagnosis is primarily clinical, with treatment guided by severity 3
Postoperative Issues
- Even after successful surgical resection of the aganglionic segment, patients may continue to have obstructive symptoms, enterocolitis, or fecal incontinence 2
- Systematic postoperative evaluation includes examination under anesthesia, contrast studies, endoscopy, anal sphincter function testing, and colonic motility studies 2
- Treatment addresses specific pathophysiological mechanisms and may include medical management, botulinum toxin injection to the anal sphincter, or rarely redo-operation 2