Congenital aganglionosis of the distal bowel of unknown etiology. Begins with the anus, which is always involved, and continues proximally for a variable distance. Both the myenteric (Auerbach) and submucosal (Meissner) plexus are absent, resulting in reduced bowel peristalsis and function.
- Transition zone from abnormally small distal to dilated proximal colon
- Normal rectum should always be larger than sigmoid
- Patients do not pass meconium within the first 24 hours of life.
- Abdominal distension with bilious vomiting or nasogastric aspirates.