What does left kidney hydronephrosis mean?

Left hydronephrosis results from obstruction of the left urinary outflow tract, leading to urine retention in the renal pelvis and calyces. It can be diagnosed by ultrasound or CT imaging. The most common cause is urinary stones, particularly ureteral calculi, which frequently lead to hydronephrosis. Patients often present with flank or abdominal pain, hematuria, and urinary discomfort. Other causes include left ureteral stricture, benign prostatic hyperplasia, or tumors, all of which may result in left-sided hydronephrosis.