Hydronephrosis Overview and Definition

Hydronephrosis is a condition defined by the swelling of one or both kidneys. It is not a primary disease but a secondary result of an underlying problem. It occurs when urine cannot drain properly from the kidney to the bladder, causing it to accumulate in the renal pelvis and calyces. This buildup creates pressure that stretches the delicate kidney structures.

In a healthy system, kidneys filter waste from the blood and send urine through the ureters to the bladder. When this flow is blocked or when urine flows backward in a condition known as “vesicoureteral reflux,” the kidney begins to expand, which can lead to tissue damage and impaired function if not treated.

The term “hydronephrosis” means “water-kidney” and may affect one kidney (unilateral) or both (bilateral). While one healthy kidney can often compensate, bilateral hydronephrosis is a medical emergency requiring prompt treatment to prevent kidney failure. Severity ranges from mild to severe, depending on the degree of dilation and thinning of kidney tissue.

At Liv Hospital, hydronephrosis is approached as a critical structural condition, with a focus on identifying and treating the underlying cause to protect long-term kidney function.