Hirschsprung disease

• abnormal innervation of the bowel beginning at the anus and extending proximally; Absence of intramural ganglion cells in
  rectum and variable distance proximally
• Functional distal bowel obstruction

Presentation

• Present with delayed passage of meconium, emesis, abdomenal distention and colitis in infants
• Affected infants often fail to pass meconium within the first 48 hours of life, but rarely do they develop symptoms of small intestinal obstruction during this period.
• Later presents as chronic constipation, rectal exam reveals increased tone with empty rectal vault

Diagnosis

• The disorder can usually be diagnosed by barium enema if a "transition zone" in which a funnel-shaped area of intestine has a proximal dilation (normally innervated) and distal narrowing is visualized. Note: do not prep the bowel beforehand, as this "erases" the transition zone
• Often the rectum is larger than the sigmoid colon.
• Failure to pass the barium on a delayed film 24 hours later is suggestive of Hirschsprung disease, even in the absence of a transition zone.
• definitive dx is rectal biopsy

Treatment

• Rx: colostomy then pull through

Also see:
Meconium Ileus
Associated with Waardenburg Syndrome