Type III posterior urethral valves: presentation and management.

The clinical and radiographic presentation of infants with type III posterior urethral valves help to distinguish them from patients with the more common type I valves. The diaphragmatic valvular obstruction may make catheterization impossible. Percutaneous cystography can confirm the diagnosis and allow for short-term decompression. The presence of smooth-walled bladders with narrow posterior urethras is unique to type III valves but is not always present. Type III valves present within a spectrum of clinical severity; however, the majority involve significant renal impairment. The prognosis for survival and renal function appears poorer for patients with type III valves than for those with type I valves.