Diagnosis

The diagnosis can be suspected on the basis of the clinical findings, and is firmly established by:

• rectal biopsy, which is usually obtained under anaesthesic as a punch or suction biopsy. A positive biopsy will document the absence of ganglion cells; this can be confirmed by staining for acetylcholinesterase
• anorectal manometry: rectal distention demonstrates an absence of the normal rectoanal inhibitory reflex
• barium enema: shows an undilated rectum, a narrow transitional zone, and a very dilated proximal bowel.