Hirschsprung Disease Workup

Hirschsprung disease is a congenital condition affecting the lower most aspect of the intestine (rectum or sigmoid), characterized by missing ganglion cells in the submucosal and myenteric plexus that allow the intestine to relax.

In Hirschsprung disease, the rectum and lowest part of the colon are always affected, with the aganglionosis always ending right above the anus.

About 85% of Hirschsprung cases begin in the very end part of the sigmoid colon or the beginning of the rectum.

In about 10% of Hirschsprung cases, the entire colon is affected.

90 to 95% of Hirschsprung cases are recognized in the newborn period.

The first sign of Hirschsprung disease in newborns is usually failure to pass stool (meconium) within the first 24 to 48 hours.

After failure to pass meconium, newborns with Hirschsprung disease develop bloating, continued failure to pass stool, and vomiting.

In newborns with suspected Hirschsprung disease, the initial workup includes a water-soluble contrast enema looking for a narrower distal segment (rectum) with dilation above.

If contrast enema raises concern for Hirschsprung disease, a suction rectal biopsy is performed to examine tissue for the presence of ganglion cells.

In older children, Hirschsprung disease can be missed and typically presents with failure to thrive (small for age) and significant constipation.

Children with Hirschsprung disease very rarely thrive and develop normally.

In older children with suspected Hirschsprung disease, the diagnostic pathway includes plain films to assess degree of constipation, followed by contrast rectal enema, and then biopsy depending on findings.

In older children with low-risk presentations (normal early years, then worsening constipation), biopsy should usually be done only after routine constipation management measures are tried and fail.

Anorectal manometry uses a balloon catheter to measure pressures in the anus and rectum, specifically looking for the rectoanal inhibitory reflex.

The normal rectoanal inhibitory reflex causes the anal sphincter to relax when a balloon is inflated in the rectum, but this reflex is absent in Hirschsprung disease.

Anorectal manometry is not sufficiently sensitive to rule out Hirschsprung disease; a normal manometry does not completely exclude the diagnosis.

Suction rectal biopsy can be performed at the bedside in newborns and is reliable up to one year of age.

After one year of age, biopsy should be performed in the operating room under anesthesia to obtain tissue from higher in the rectum.