Hirschsprung Disease

Background

• Hirschsprung disease is a functional intestinal obstruction due to the absence of ganglion cells in all or part of the myenteric and submucosal plexuses of the distal intestine.
  • The majority of disease is limited to the rectosigmoid region.
  • Disease beyond the rectosigmoid region (long-segment disease) is less common, with rare occurrences of total colonic aganglionosis or total colonic and small bowel aganglionosis.
• The disease usually presents during infancy with a male:female ratio of 4:1. Infants born at < 37 weeks gestational age may be diagnosed later than infants born at term.
• Family history and Down syndrome are major risk factors for Hirschsprung disease.
• Other congenital abnormalities may be seen in up to 30% of children.

Evaluation

• Presenting symptoms vary with age and the presence of enterocolitis (seen in 10%-33%).
  • Symptoms in neonates and young infants may include passage of meconium > 24-hours old, abdominal distention, bilious vomiting or feeding intolerance, infrequent, explosive, or difficult bowel movements, and jaundice.
  • Symptoms in older infants and children may include chronic constipation, reduced or absent soiling with fecal impaction, overflow incontinence, abdominal distention, and failure to thrive or malnutrition.
  • Symptoms of enterocolitis may include fever, diarrhea, vomiting, progressive abdominal distention, explosive stools, lethargy, poor feeding, and hematochezia.
• A contrast enema is the preferred initial test, with a funnel-shaped transition zone being pathognomonic for Hirschsprung disease. A rectosigmoid ratio of < 1 on contrast enema or anorectal manometry (in older children) showing a negative rectoanal inhibitory reflex may be suggestive of Hirschsprung disease.
• Any positive or suggestive results in neonates should be followed by a suction rectal biopsy performed ≥ 1.5 cm (0.6 inches) above the dentate line to confirm the diagnosis.
• Histologic evaluation showing an absence of ganglion cells and the presence of hypertrophic nerve trunks in the myenteric and submucosal plexus confirms the diagnosis.
• A full-thickness biopsy will be needed if the suction biopsy does not provide an accurate diagnosis.

Management

• Initial treatment involves fluid resuscitation and stabilization.
• Children with obstruction or enterocolitis symptoms should receive gastric decompression with nasogastric tube, IV fluids, and broad-spectrum antibiotics.
• Definitive treatment is surgical excision of the affected segment of intestine:
  • required in almost all children except those with ultrashort segment disease (as determined by a full-thickness biopsy during surgery)
  • transanal pull-through is the usual procedure in children with short-segment disease
  • transabdominal approach may be required in children with long-segment disease or total colonic aganglionosis
• Timing of definitive surgical repair:
  • is usually performed soon after presentation or resuscitation and stabilization
  • may be delayed in older children presenting with extremely dilated colon if rectal decompression by irrigation can reduce colon diameter preoperatively
  • associated conditions should be investigated and managed prior to surgical repair if they are causing symptoms or will complicate surgery
  • colostomy may be required prior to definitive repair in children with severe enterocolitis, intestinal perforation, malnutrition, massively dilated proximal bowel, total colonic aganglionosis, or unreliable identification of transition zone during surgery
• Permanent ileostomy may be needed in children with total colonic aganglionosis or total colonic and small bowel aganglionosis.