What is the definitive diagnostic test for Hirschsprung disease?

What is the definitive diagnostic test for Hirschsprung disease?

• A. Rectal biopsy
• B. Anorectal manometry
• C. Barium enema
• D. Abdominal radiographs

Answer: (A)

Hirschsprung disease is diagnosed definitively by showing absence of parasympathetic ganglion cells in the distal colon. A rectal suction biopsy provides tissue from the submucosa, and histology reveals lack of ganglion cells in both the submucosal (Meissner) and myenteric (Auerbach) plexuses. Often the specimen also shows hypertrophic nerve trunks and there may be increased acetylcholinesterase activity, which supports the diagnosis. This direct visualization of absent ganglion cells is what makes rectal biopsy the definitive test. Other tests can help suggest the diagnosis but are not definitive on their own: anorectal manometry assesses reflexes and sphincter function but does not confirm histology; a barium enema can show a transition zone but isn’t specific; abdominal radiographs show distention or fecal loading but do not establish the diagnosis.

Hirschsprung disease is diagnosed definitively by showing absence of parasympathetic ganglion cells in the distal colon. A rectal suction biopsy provides tissue from the submucosa, and histology reveals lack of ganglion cells in both the submucosal (Meissner) and myenteric (Auerbach) plexuses. Often the specimen also shows hypertrophic nerve trunks and there may be increased acetylcholinesterase activity, which supports the diagnosis. This direct visualization of absent ganglion cells is what makes rectal biopsy the definitive test.

Other tests can help suggest the diagnosis but are not definitive on their own: anorectal manometry assesses reflexes and sphincter function but does not confirm histology; a barium enema can show a transition zone but isn’t specific; abdominal radiographs show distention or fecal loading but do not establish the diagnosis.