How long does abdominal distension associated with hirschsprung disease last?

Depends : A lot depends on if the hirschsprung's has been repaired. If not the distension can be recurrent. If surgically treated it should resolve quickly, although there is always a likelihood for hirschsprung's enterocolitis which can cause distension.

Age of correction: Most hd is diagnosed in infants and children. If delayed, the intestine become very dilated and less functional and remains distended. Early only, regular enemas will allow the bowel to come down in size. However, it may be a sign of recurrent/retained hd or a dysfunctional anal sphincter. This should be evaluated if continues. It also can be a sign of enterocolitis. Needs evaluation.