What is the role of air-contrast enemas in the workup of pediatric constipation?

Updated: Dec 14, 2018
  • Author: Stephen M Borowitz, MD; Chief Editor: Carmen Cuffari, MD  more...
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Do not use an air-contrast enema when looking for Hirschsprung disease, because radiographic evaluation of Hirschsprung disease depends on finding a change in colonic caliber between the normal and abnormal aganglionic segment. With an air-contrast study, the colon is evacuated prior to the study to identify mucosal abnormalities. By evacuating the colon before the study, any caliber change may be masked.

Moreover, do not perform any form of rectal manipulation on the child (eg, rectal examination, therapeutic enema, suppository) for 48 hours before the procedure. Rectal manipulation with suppositories or therapeutic enemas may transiently dilate the narrowed distal segment, causing a false negative result.

Although an unprepared barium enema has reasonably good diagnostic sensitivity and specificity in older children, this procedure is substantially less reliable during the first several months of life. The proximal colon may require several months after birth to dilate sufficiently for a transition zone to be apparent.

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