Illustration of an obstructed ureteropelvic junction resulting in dilation of the kidney (hydronephrosis) and thinning of the kidney parenchyma (above). Radiographic finding of left UPJ obstruction with absent drainage of contrast down the ureter, and dilation of the left kidney (below).
Ureteropelvic junction obstruction (UPJO) is an anatomical obstruction at the junction of the ureter and the kidney which prevents complete drainage of urine from the kidney. It can be congenital (since birth) or acquired later in life. The congenital causes of UPJ obstruction include a crossing vessel, high insertion of the ureter, or a non-peristalsing segment of ureter. Acquired causes of UPJ obstruction include previous impacted stone, instrumentation of the urinary tract, history of radiation, external compression from an abdominal mass, or idiopathic.
Many patients can be without symptoms while others many have any of the following signs or symptoms:
- Flank pain
- Dietl's crisis- Flank pain after high fluid or caffeine intake
- Recurrent urinary tract infections
- Severe infection known as Sepsis
Untreated UPJ obstruction causes dilation of the kidney known as hydronephrosis. Prolonged hydronephrosis can cause irreversible damage to, or even loss of the kidney.
If you have any of the above symptoms, you should be referred to a urologist to evaluate for this condition. Your urologist will order the appropriate testing to determine the underlying cause of your UPJ obstruction and evaluate the health of your kidney. If your kidey function is appropriate, your surgeon will discuss an operation known as pyeloplasty to remove the obstructed segment to allow your kidney drainage to improve. This operation can often be performed in a minimally invasive fashion using the Da Vinci Robotic system. If your kidney does not function and you are experiencing symptoms, your surgeon may discuss removal of the nonfunctioning kidney, known as simple nephrectomy.