Diagnosing Hirschsprung's disease: increasing the odds of a positive rectal biopsy result.

Background/purpose: Rectal biopsies are performed as a definitive means of diagnosing Hirschsprung's Disease (HD) in children presenting with constipation. The authors hypothesized that key features in the history, physical examination, and radiographic evaluation would allow us to avoid unnecessary rectal biopsies.

Methods: A retrospective analysis was conducted on patients undergoing rectal biopsy between 1995 and 2001. Patients with HD were identified (n = 50), and a concurrent cohort of patients with idiopathic constipation (IC; n = 50) was selected. Pertinent features in patients with HD versus those with IC were cross tabulated using Pearson Chi2 testing (significance was P <.05).

Results: Sixty percent of patients with HD and 15% of patients with IC experienced onset of symptoms in the first week of life. HD patients more frequently experienced delayed passage of meconium (P <.05), abdominal distension (P <.05), vomiting (P <.05), and transition zone on contrast enema (P <.05). All patients with HD had one or more of these significant features. In contrast, only 64% of patients with IC had one or more of these features. The classic triad of symptoms (ie, delayed passage of meconium, vomiting, and abdominal distension) was present in 18%, and one or more of these symptoms was present in 98% of HD patients. In contrast, only 60% of patients with IC had a history of delayed passage of meconium, vomiting, or abdominal distension.

Conclusions: A history of delayed passage of meconium, abdominal distension, vomiting or the results of a contrast enema identified all patients with HD and excluded HD in approximately 36% of patients with idiopathic constipation. The authors have shown that key features in a patient's history, physical examination, and radiologic evaluation can differentiate between HD and IC. In a child presenting with constipation and none of the above features, it is not necessary to perform a rectal biopsy to exclude HD.