Hydronephrosis

Hydronephrosis is a condition that affects the kidneys, which are vital organs responsible for filtering waste from the blood and producing urine. It occurs when urine cannot drain properly from the kidney to the bladder, causing the kidney to swell. This swelling happens because urine builds up, leading to increased pressure inside the kidney. The main health concern is that this pressure can damage the kidney tissue over time, potentially reducing kidney function. Symptoms may include pain in the side or back, urinary problems, or sometimes no symptoms at all. Early detection is important to prevent permanent kidney damage.

Hydronephrosis is defined as the dilation and distension of the renal pelvis and calyces due to obstruction of urine flow downstream, leading to increased intrarenal pressure. The core pathology involves urinary tract obstruction, which can be caused by intrinsic factors such as stones, strictures, or tumors, or extrinsic compression from masses or fibrosis. This obstruction impairs normal urine drainage, resulting in renal pelvis dilation and potential renal parenchymal atrophy if untreated. Clinically, it is significant because prolonged obstruction can cause irreversible kidney damage and impaired renal function. It may present with flank pain, urinary tract infections, or be asymptomatic and detected incidentally on imaging. The severity ranges from mild pelvic dilation to severe cortical thinning.