Posterior Urethral Valves

What is Posterior Urethral Valves?

Posterior urethral valves is a condition in boys in which the urethra, below the bladder, is partially obstructed by a membrane. It is a developmental problem, which causes severe urine flow impairment and high pressures. This results in a very thick, muscular and abnormal bladder, which strives to overcome the obstruction, also seen in severe hydronephrosis, affecting usually both kidneys and their ureters. This is a severe condition and occurs in approximately 1 in 3000 boys. In its most severe manifestations, the kidneys are destroyed, and during pregnancy the fetus may be unable to survive. The majority of such cases however, come to be born and require the intervention of a Paediatric Urologist.

Nowadays, posterior urethral valves is commonly diagnosed antenatally. Certainly, the more severe types are known before the child is born and counseling can be offered to the parents, to educate them concerning the most appropriate course of action postnatally. After birth, a catheter is placed in the patient’s bladder to drain the urine, and this gives maximum relief to the kidneys. Other childhood issues, such as difficulty breathing, often associated with severe posterior urethral valves, can then be resolved. A cystoscopic procedure to resect the valves and create a clear passage of urine to the outside is then performed at an optimal time, usually around 2 or 3 weeks of age.

The implications of posterior urethral valves however persist beyond this time. The obstruction of the kidneys during early development can lead to long-term malfunction, and so it is usual for these more severe patients to be monitored by a Paediatric Nephrologist. The severe cases will commonly lead to renal failure, and the need for dialysis and treatment in later life.

From a Urologist’s point of view, the bladder may continue to be a problem in spite of resolution of the valves. These patients may have long-term issues with continence and secondary damage to their kidneys due to a high-pressure bladder. They are a demanding group of patients, and often ultimately require bladder reconstruction and renal transplantation.

Fortunately, the majority of patients with posterior urethral valves are not quite as severe as this and prompt, early treatment and attention during childhood, can lead to excellent long-term outcomes in terms of renal and bladder function.