Treatment of sickle cell trait hematuria with oral urea.

Unilateral hematuria is a vaso-occlusive complication of the sickle syndromes, especially the sickle cell trait. Treatment is usually ineffective, and the duration is variable, often prolonged and subject to recurrences. In sickle cell trait hematuria is usually the only consequence of sickling, possibly because the unique renal countercurrent mechanism may result in a milieu more prone to sickling in the medullary circulation than in the vasculature of other organs. Urea in vitro inhibits gelation of deoxygenated sickle hemoglobin. In 2 previously reported cases of sickle cell trait hematuria ceased within 3 days with oral urea therapy. We describe another such patient in whom hematuria also ceased by day 3 with oral urea. Although clinical trails with intravenous urea were ineffective in shortening the course of sickle crisis, urea may have an enhanced effectiveness in the renal medulla where the propensity for sickling may be much greater than in other organs. If these observations are confirmed in a controlled study, oral urea therapy would emerge as an effective, relatively innocuous and inexpensive treatment for this frustrating condition.