Hydronephrosis

Hydronephrosis is an accumulation of fluid in the kidneys found on ultrasound- this can be found before or after the baby is born. Kidneys filter out the waste found in the blood and make urine.  This urine should then drain down the ureter (tube between the kidney and bladder) to the bladder and the patient should then void this out.  Sometimes the urine can accumulate in the kidney for different reasons.  The fluid/urine in the kidney is not necessarily an indication there is something wrong (and many times can go away on its own with time), but is an abnormality that is important to follow so as not to miss a possible issue such as ureteropelvic junction (UPJ) obstruction and ureterovesical junction (UVJ) obstruction.