Our kidneys produce urine by filtering and purifying the blood and completely eliminating wastes, salts and water. The urine is then drained from the kidneys through a funnel-shaped structure called the Renal pelvis into a natural tube called the ureter. Each kidney should have at least one functional ureter to transport the urine from the kidney to the bladder.
Ureteropelvic junction (UPJ) obstruction refers to a condition which causes obstruction in the flow of urine from the renal pelvis to the proximal ureter. In most cases, the reason for this condition is purely congenital, where the obstruction occurs at the ureteropelvic junction (UPJ); the point where the ureter joins the renal pelvis. This problem usually occurs in one in 1,500 children.
These obstructions are generally diagnosed on prenatal ultrasound screening.
UPJ obstruction results in excessive accumulation of urine within the kidney, also called Hydronephrosis. Although this condition is encountered very rarely in adults, UPJ obstruction may happen due to kidney stones, previous surgery or disorders that can cause swelling of the upper urinary tract.
- Abdominal mass
- Urinary tract infection with fever and flank pain especially with increased consumption of fluid, stones and blood in urine.
- Pain without an infection.
- Urine may drain in a normal manner at one time and may get completely obstructed which causes sporadic pain.
In order to diagnose this condition, a functional test or a test that assesses the ability of the kidney to produce and drain urine, should be performed. The classic examination which is performed is the ‘Intravenous pyelogram (IVP)’. In this test, a particular type of dye is injected into the blood stream. When the kidneys eliminate this substance from the blood, it passes into the urine and finally out of the bladder. With the help of an X-ray, the physician can identify the shape of the kidney, renal pelvis and ureter. Another test used in children is the ‘Furosemides renal scan.’ In this test, a radioactive material is used instead of the dye. This test can provide more precise information regarding the potential of the kidney to produce and drain urine.
Treatment of Ureteropelvic Junction (UPJ) Obstruction
Poor drainage from the kidneys due to UPJ in infants and young children who are less than 18 months of age may be in fact temporary. Infants with good kidney function and poor drainage will showcase a significant improvement in drainage over the first few months. However, some children will not show any improvement and some others will get worse. Hence, patients suffering from hydronephrosis kept under close observation with repeat CT scans and ultrasounds. If UPJ obstruction is diagnosed and confirmed and there is no further scope for improvement, the condition requires immediate surgical treatment.
The basic treatment of UPJ obstruction is a Pyeloplasty which involves removing the UPJ and reattaching the ureter to the pelvis of the kidney. This enables easy drainage of urine produced by the kidney and does away with symptoms and the risk of infection. The procedure generally takes only a few hours. Open surgery is almost given up for this condition and treatment is by Laparoscopy. (Minimally invasive approach). Endopyelotomy which was an endoscopic approach has poor results in primary UPJ obstruction and is reserved for secondary UPJ obstruction (secondary to previous surgery)
Laparoscopic Pyeloplasty is performed through the abdominal cavity and may cause scarring or adhesions within the abdomen. However, the most important advantages of laparoscopic surgery are minimal pain and nausea particularly in older children and adults.
What can be expected after treatment for UPJ obstruction?
There could be inflammation in the ureter and poor drainage of the kidney for some time. However, this usually diminishes as the region heals. The surgeon generally performs a functional test, a few weeks after the procedure, in order to evaluate the functioning of the kidney. Patients often recover quickly after these procedures. Once a UPJ obstruction is repaired, it is never likely to occur again.