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Urology
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Kidney Obstruction

How is kidney obstruction discovered ?
When the kidney is obstructed, the urinary drainage system that transmits urine from the kidney to the bladder is dilated (enlarged). It is not uncommon to see dilation of the kidney drainage system of a fetus before birth, which may be discovered when a pregnant woman has an ultrasound. When we test these children after birth, we may find one of the following:

  • the dilation is gone
  • the urinary drainage system is blocked (obstructed)
  • urine is backing up into the kidney(s) from the bladder (a problem called reflux)
  • the urinary drainage system remains enlarged but there is no obstruction or reflux

In older children, obstruction may be discovered when the child has pain in the side, vomiting, urinary tract infection or high blood pressure.

What is the significance of kidney obstruction ?
Whether obstruction causes damage to kidney function depends on the degree of blockage and the age of the patient.

What tests are needed to identify the severity of the problem ?
The first test, which usually identifies the problem, is a kidney (renal) ultrasound. In some cases, a kidney X-ray (IVP) or a CAT scan has been done. We recommend 2 other tests: a bladder X-ray (VCUG) to rule out reflux and a renal scan to measure kidney function.

  • VCUG- In this test, a catheter (tube) is passed into the bladder. The bladder is filled with dye or tracer and pictures are taken.
  • Renal scan - In this test, a catheter is usually needed as well. A small amount of a tracer substance is injected into a vein. Pictures are taken with a camera for an hour or longer. Early in the test, a drug that stimulates urine production (lasix) is given to wash urine out of the kidneys. This test tells us how well each kidney works as compared to the other kidney and how fast each kidney drains out. Kidneys which do not drain well are obstructed, and the point of blockage can be seen on the scan. A blood test is obtained to measure creatinine, which tells us how good your child¹s overall kidney function is.

What causes obstruction ?
The most common kind of obstruction is blockage of the urinary drainage system at the beginning of the ureter, or the tube that connects the kidney and bladder. This is called ureteropelvic junction obstruction. The ureter may also be blocked at its connection with the bladder, called ureterovesical junction obstruction. If the lower ureter is dilated like a balloon, a ureterocele is present, which may block drainage from both kidneys, or half of one kidney.

How is obstruction treated ?
If obstruction is mild or partial, your doctor might suggest that it be observed for awhile. In other cases, surgery is always recommended. If we decide to wait and observe your child, we will recommend repeating the ultrasound and the kidney scan usually 6-12 months later. If your child should become ill, especially with fever, prior to your next visit, you should have his/her urine checked for infection.

What surgical treatment might be recommended ?
If the obstruction is severe or if a ureterocele is present, surgery will be recommended.

  • Ureteropelvic junction obstruction. The procedure to repair this blockage is called pyeloplasty. We usually perform this procedure through an incision in the back. The operation requires general anesthesia. After your child is asleep, we usually pass a needle to inject dye and take pictures to confirm that there is only one area of blockage. The repair is done by removing the blocked section and sewing the drainage system back together. We will leave a soft drainage tube coming out the skin for about 1 week. We may also leave a catheter in the bladder or the kidney. These tubes may all be removed before your child leaves the hospital or left in place until he/she returns to the office. Once they are removed, your child can bathe or shower. All the stitches dissolve on their own.
  • Ureterovesical junction obstruction. An incision is made in the lower abdomen. The area of blockage is removed and the ureter is sewn into the bladder (ureteral reimplantation). Sometimes it is necessary to taper (narrow) the ureter. Afterwards, a tube is left in the bladder and sometimes a ureteral stent and a kidney drainage tube are also left. These tubes will be removed in the hospital or office.
  • Ureterocele. Options for treatment include making a hole in the ureterocele, removing it from the bladder or removing its entire drainage system, including the upper half of the kidney. Your doctor will discuss these options with you and choose the best procedure for your child.

How do I care for my child after surgery ?
After any of these procedures, your child will remain in the hospital for at least several days. A normal diet will gradually be resumed. He/she will be given pain medicine and antibiotics. No stitches will be removed from the incision since they all dissolve. We will encourage your child to take deep breaths and get out of bed as soon as possible after surgery.

What problems can occur after surgery ?
As with any surgery, bleeding or infection can occur, but are rare. When blockage is repaired, the area that is fixed can swell and remained blocked for a time. If a drainage tube is already in place, it will remain there until the blockage is gone. Occasionally it is necessary to put a drainage tube into the kidney temporarily. If blockage persists or recurs, however, another operation may be required. This complication occurs infrequently (less than 10% of the time). When the ureter is sewn into the bladder (reimplant), the obstruction may be cured but reflux (backflow of urine from the bladder to the kidney) may start. If this problem persists for a year or longer, surgical repair may be required.

What happens after surgery ?
If a drainage tube was left in place at the time of surgery, your doctor may do an X-ray to make sure everything has healed before it is removed. If no tube was left, we will often do an ultrasound 1-2 months after surgery. A renal scan will also be required to make sure that the obstruction is gone. The number of tests done after surgery varies from person to person. However, we may do ultrasounds for up to 5 years after surgery to make sure that the kidney dilation is gone.