Overview

• Congenital condition in which nerve cells of the myenteric plexus are absent in the distal bowel and rectum.
  • Responsible for stimulating peristalsis of the large bowel. Without this stimulation the bowel loses its motility and stops being able to pass food along.
  • Absence of PARASYMPATHETIC ganglion cells → due to them not travelling all the way down the colon, a section at the end is left without them.
  • ‘Aganglionic’ section of colon does not relax, causing it to become constricted. Leads to loss of movement of faeces (uncoordinated peristalsis) and obstruction in the bowel.
  • Hypertonic Bowel → fails to relax.
• Associations → down’s syndrome, neurofibromatosis, MEN II.

Making Diagnosis

Clinical Features

• Delay in passing meconium (>24 hours).
• Chronic constipation since birth.
• Abdominal pain and distension.
• Bilious vomiting.
• Poor weight gain and failure to thrive.

Investigations

• Abdominal X-Ray → diagnosing intestinal obstruction. Air fluid levels.
• Rectal Biopsy (full-thickness) → gold standard. Histology will demonstrate absence of ganglionic cells in auerbach’s plexus.

Management Plan

• Initial → rectal washouts / bowel irrigation.
  • Soften faeces and flushes it from the bowel.
• Definitive → surgical removal of aganglionic section of bowel (anorectal pull through).