Urinary tract dilatation in constipated children. Abnormalities of the upper urinary tract were sought retrospectively in 180 children with constipation who had been investigated surgically over a 5-year period. Of those in whom an intravenous urogram had been performed, the incidence of dilatation of the upper renal tract was high, but only 12% of the patients with non-organic constipation had been so investigated. 