URETEROPELVIC JUNCTION OBSTRUCTION

What is ureteropelvic junction obstruction?

One of the main jobs of the kidney is to filter the blood, and deliver the waste products (urine) to the bladder. The urine leaves the kidney, enters the renal pelvis, and then passes into the ureter through a funnel called the ureteropelvic junction (UPJ). In some children there can be a partial blockage at the UPJ. The blockage may be severe (high grade), minimal (low grade) or intermittent.

What are symptoms of UPJ obstruction?

The obstruction is usually due to an abnormality in the development of the muscle at the UPJ and causes urine to back up into the kidney. We detect many patients with UPJ problems before birth because of enlargement of the kidney (hydronephrosis) seen on the prenatal ultrasound. Older children may have pain (related to the blockage), urine infection (due to stagnation of urine caused by the UPJ blockage), or kidney stones. Prolonged blockage, particularly with infection, can damage the kidney.

How is UPJ obstruction diagnosed?

Ultrasonography and intravenous urography (IVU) will show hydronephrosis (enlargement of the kidney) related to the UPJ obstruction. Other studies, such as a diuretic renal scan (DRS) may be needed to evaluate the function of the kidneys.

How is UPJ obstruction treated?

The usual repair of a UPJ obstruction (pyeloplasty) involves removing the blockage, and reconnecting the ureter to the renal pelvis. Depending on the individual circumstances a tube may be left across the pyeloplasty (stent) or a tube may be left above the repair to decompress the kidney (nephrostomy).

How are children followed after pyeloplasty (repair of UPJ obstruction)?

A child should be followed for at least several years after a pyeloplasty. Even after successful repair of a UPJ obstruction, the deformity in the kidney (mainly the hydronephrosis) persists and an ultrasound or IVU will still "look abnormal". Tests that evaluate kidney function, such as the DRS, are better ways to follow children after repair.