Pediatric hydronephrosis occurs when urine collects in the kidney due to a blockage or coming back up from the bladder. When that happens, the kidneys become swollen and urine doesn’t drain out effectively.
Kidneys clean blood to remove liquid wastes, which are turned into urine. Urine collects in the area of the kidney known as the renal pelvis. From there, it goes through a ureter (a narrow tube) to the bladder. Urine leaves the body after it travels from the bladder through the urethra.
When this regular flow is disrupted, it's known as hydronephrosis. This can occur in one or both kidneys, and can be mild or severe.
Hydronephrosis is caused by the ureter becoming blocked, due to kidney stones, or when urine backs up from the bladder to the kidney, called vesicoureteral reflux. Hydronephrosis can also be a genetic condition (passed down from parents to child) detected while a baby is still in the womb.
Symptoms of this condition include: