Discussion of Hirschsprung disease
- Hirschsprung disease is a form of low intestinal obstruction
- Caused by the absence of normal myenteric ganglion cells in a segment of the colon.
- Accounts for approximately 15%–20% of cases of neonatal bowel obstruction.
- The aganglionosis varies in length but always extends proximally from the anal canal, and the rectosigmoid area is involved in 80% of cases.
- Ultrashort segment disease (in which aganglionosis is essentially limited to the region of the internal sphincter) is very rare
- Aganglionosis involving the entire alimentary tract is also very rare.
- Absence of ganglion cells results in the failure of the distal intestine to relax normally.
- Peristaltic waves do not pass through the aganglionic segment and there is no normal defecation, leading to functional obstruction.
- Abdominal distention, constipation, and bilious vomiting are the predominant signs and symptoms of obstruction and appear within a few days after birth.
 Imaging Findings for Hirschsprung disease
- Radiography performed in children with Hirschsprung disease yields findings similar to those in other forms of low small bowel obstruction: variable gaseous distention of the colon and small bowel, often with air-fluid levels.
- The colon is usually difficult to identify accurately, and gas is usually absent in the rectum.
- Barium enema studies demonstrate patency of the colon, which is short but usually normal in caliber.
- A transition zone between the narrow and dilated portions of the colon in the shape of an inverted cone is the most characteristic radiologic finding.
- When this transition zone is observed, the examination should be discontinued because filling of the more proximal dilated bowel beyond the transition zone may lead to impaction.
- The radiologic diagnosis of total colonic aganglionosis is difficult. Findings at barium enema examination may be normal or may include a short colon of normal caliber, microcolon, or a transition zone in the ileum.
 See Also
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 References for Hirschsprung disease
- Teresa Berrocal, Manuel Lamas, Julia Gutiérrez, Isabel Torres, Consuelo Prieto, and María Luisa del Hoyo. Congenital Anomalies of the Small Intestine, Colon, and Rectum. RadioGraphics 1999 19: 1219-1236.