Hydronephrosis

Hydronephrosis in children refers to the enlargement of the renal pelvis and calyces due to urine buildup. The most common causes are congenital abnormalities, such as narrowing of the junction between the renal pelvis and ureter, or vesicoureteral reflux, where urine flows back from the bladder into the kidneys. It can be asymptomatic or cause abdominal pain, urinary tract infections, and reduced urination.