One of the most common forms of obstructive urethral lesion in male neonates and infants and the most common cause of chronic renal disease in boys. Posterior urethral valves (PUV) are mucosal folds located in the distal prostatic urethra that result in varying degrees of obstruction and damage to urinary bladder and tract. The precise cause is unknown; research indicates a genetic component may be at play as PUV may sometimes occur in families. PUV may be detected prenatally via ultrasonography. Postnatally, patients are most commonly diagnosed as neonates or infants, although in some cases the condition is not detected until childhood.

Patients present with mild, moderate, or severe clinical symptoms of obstruction depending on severity and age of onset. Typical symptoms include abdominal mass representing a distended bladder, difficulty voiding, enuresis, failure to thrive, urinary frequency, urinary tract infection, and weak urinary stream. Common laboratory findings include anemia, azotemia, elevated serum creatinine, and elevated serum urea nitrogen.

In severe cases, complications include bladder dysfunction, renal impairment, respiratory distress, severe hydronephrosis, and vesicoureteral reflex. Patients are at increased risk of developing kidney failure. The most severe complication is pulmonary hypoplasia due to intrauterine oligohydramnios.

The presence of bilateral reflux or elevated nadir serum creatinine within the first year of life may indicate poor prognosis. A majority of these patients have delayed urinary continence development due to bladder changes and impairment of urinary concentration.

Treatment is dependent on the degree of obstruction; patients require individualized management. Treatment typically involves endoscopic ablation and resection, but may also include antibiotics, catheter drainage, and electrolyte and fluid imbalance correction.