Hereditary nephrogenic diabetes insipidus and bilateral nonobstructive hydronephrosis.

We describe 2 cases of hereditary nephrogenic diabetes insipidus with massive bilateral dilatation of the urinary tract without any organic obstruction. A review of the literature revealed that dilatation of the urinary tract was present in 67% of the reported cases of nephrogenic diabetes insipidus which included a description of the urinary tract. This strong association between hereditary nephrogenic diabetes insipidus and nonobstructive hydronephrosis suggests a cause-and-effect relationship in which polyuria is responsible for the hydronephrosis.