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Renal Resource Centre 37 Darling Point Poad, Darling Point, NSW 2027 AUSTRALIA Telephone: 61 2 9362 3995 9362 3121 Facsimile: 61 2 9362 4354 Freecall: 1800 257 189 Click here for our location map |
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Renal Resource Centre 37 Darling Point Poad, Darling Point, NSW 2027 AUSTRALIA Telephone: 61 2 9362 3995 9362 3121 Facsimile: 61 2 9362 4354 Freecall: 1800 257 189 Click here for our location map |
The important parts of the urinary system are the kidneys themselves, the tubing system and the bladder. The kidneys act as filters removing unwanted water and waste products and passing them through the urine. The tubing system takes urine from the kidneys into the bladder by the tubes called ureters, and then from the bladder by a tube called the urethra. (see the diagram below.) The bladder stores the urine until necessary to pass it.
There is a valve at the junction of the ureter with the bladder, and when the bladder is being emptied the valve prevents the urine from travelling up the ureter towards the kidney. In urinary reflux this valve does not work properly and each time the baldder is emptied urine flows up the ureter towards the kidney.
It is not clear how common reflux is, but there are probably many children who have reflux and who never have any problems. Urinary reflux can be present in up to 25% of children who have infections of the bladder and urinary tract in up to 10% of children who have a dilated tubing system. A dialated tubing system can sometimes be diagnosed before a baby is born when the mother has a special ultrasound scan.
Reflux predisposes children to urinary infections, and particularly infection which not only involves the bladder, but also the kidney (pyelonephritus). Because the valve between the ureter and the bladder is not working properly, infected urine is pushed up the ureter to the kidney. Such urinary tract infections occur in many children who have ruflux.
In most cases this kidney damage resolves with time and complete healing occurs through the natural processes of the body. Sometimes the damge due to the infection does not heal by itself and permanent damage results. Usually this damge is only minor, but long term problems like high blood pressure can occur much later in life.
Up to one third of infants with urinary reflux have kidneys which are not formed properly (congenital damage) and have kidney damage before infection has occured.
Drawing of severe urinary reflux. Free passage of urine up the urinary tract toward the
kidney, often associated with urinary infection, can cause permanent damage to the kidneys.
Reflux does not cause any symptoms and does not cause any kidney damage on its own, in the absence of infection. Symptoms and damage occur most frequently if urine infection develops. Urine infections commonly cause fever, pain and burning when passing urine. In young children, fever may be the only symptom. If this occurs your child should see a doctor for a check-up and a urine test.
As children grow older, the valve between the ureter and the bladder can mature and reflux then disappears without any surgical treatment to mend the valve. This takes place over several years.
Because the chance of infection (particularly infection that causes kidney damage) decreases as children grow older, persistant reflux does not matter in school age children but you should always check with your doctor.
Reflux is diagnosed by a micturating cystourethrogram (MCU). This x-ray test involves passing a fine tube through the urethra (the natural passage into the bladder) and filling the bladder to see whether there is reflux of the dye back up the ureter towards the kidney. Fifteen minutes is usually all that is required, and while the test sounds unpleasant, it is usually quite tolerable for the child. An ultrasound examination of the kidneys is also done to make sure there is no associated kidney blockage. A radionuclide dimercaptosuccinic acid (DMSA) scan is frequently done in children with reflux to find out whether kidney damage is present. This involves an injection of a radioactive dye, and three hours later pictures are taken of the kidneys. Movement of the child results in unclear pictures, so they need to be held securely. The state of kidney health can then be accurately assessed.
Most doctors would recommend daily antibiotics to prevent further urine infections and new kidney damage occurring. These antibiotics are usually given for several years early on in life, when the risk of urine infection and kidney damage is highest. In these cases, long term antibiotic use is very appropriate and must be weighed against the risk of permanent kidney damage caused by repeated, untreated urinary tract infections. Not all antibiotics are suitable because resistance can emerge quickly e.g. penicillins, or are not suitable for children e.g. tetracyclines. A number of antibiotics have been proven to be useful in smaller doses than for acute infection e.g. Septrin, Bactrim, Keflex. Macrodantin should not be used where there is reduced kidney function. Breakthrough infections (urine infections that develop in children on antibiotics) can occasionally occur, and if they do, different preventative antibiotics can be given or sometimes surgery to fix the leaky valve can be undertaken. If surgery is necessary to repair the valve (and this is not often required), the surgeon remakes the valve mechanism at the lower end of the ureter where it enters the bladder.
Urine samples should be examined whenever a urine infection is suspected and particularly if the child has a fever.
There is no treatment that will make kidney damage resolve, apart from the body's own healing processes. If complete healing does not occur, it is important that blood pressure and urine checks are done annually.
Reflux is a long-term problem, especially if associated with kidney damage.
However, it is only a small proportion of children with reflux who develop significant kidney problems. In most children the problem is minor, and with regular visits to the doctor and preventative antibiotics, children with reflux do well with no significant long term problems.
Finally, it is important to recognised that after birth it is infection which causes kidney damage and not reflux in itself.
RENAL RESOURCE CENTRE
37 Darling Point Road, Darling Point NSW 2027
Telephone: (02) 9362 3995 or (02) 9362 3121
Facsimile: (02) 9362 4354
Toll Free: 1800 257 189
Web: www.renalresource.com
Supported by the Australian Kidney Foundation
Renal Resource Centre