The most common cause of lower urinary tract obstruction and the leading cause of end-stage renal disease in boys is which condition?

• A. Polycystic Kidney Disease (PKD)
• B. Posterior Urethral Valves (PUV)
• C. Ureteropelvic Junction Obstruction
• D. Vesicoureteral Reflux

Answer: (B)

Posterior urethral valves cause a congenital blockage of the male lower urinary tract. These obstructive folds in the posterior urethra impede urine outflow from the bladder, creating bladder outlet obstruction from birth. The resulting high pressures in the bladder and urinary tract lead to hydronephrosis and progressive renal damage, making this the most common cause of lower urinary tract obstruction and a leading cause of end-stage renal disease in boys. Other conditions involve different parts of the urinary tract or are not primarily lower tract obstruction in male children: polycystic kidney disease is intrinsic kidney disease, UPJ obstruction is an upper tract obstruction at the kidney–ureter junction, and vesicoureteral reflux describes backward urine flow rather than a primary bladder outlet obstruction.