Hirschsprung disease

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[edit] 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.

[edit] 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.

[edit] Images

Patient #1

[edit] See Also

[edit] External Links

[edit] References for Hirschsprung disease

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