Gradual and progressive loss of function in both kidneys
- Some causes are increasingly common with age
- Gender and genetics as risk factors depend on the cause
- Lifestyle is not a significant factor
In chronic kidney failure, progressive damage gradually reduces the ability of the kidneys to remove excess water and wastes from the blood. As a result, waste substances start to build up in the body. In many cases, kidney function is reduced by over 60 per cent before the build-up is detected; by this time, often after months or even years, the kidneys may be irreversibly damaged. Dialysis or a kidney transplant may therefore become necessary.
What are the causes?
Chronic kidney failure may result from disorders that progressively damage kidney tissue, such as polycystic kidney disease or glomerulonephritis. The condition may also be the result of generalized disorders, such as diabetes mellitus or high blood pressure (see Hypertension). People who have sickle-cell disease are at risk of developing chronic kidney failure if abnormal blood cells block the small vessels that supply the kidneys. Chronic kidney failure can also follow prolonged blockage of the urinary tract, such as that caused by an enlarged prostate gland.
What are the symptoms?
The initial symptoms of chronic kidney failure appear gradually over weeks or months and are often vague, such as weakness and loss of appetite. As the condition progresses, other symptoms may then develop, including:
Frequent passing of urine, particularly during the night.
Pale, itchy, and easily bruised skin.
Shortness of breath.
Nausea and vomiting.
Pins and needles.
Cramps in the legs.
The condition is associated with a number of complications, such as high blood pressure, which may be an effect as well as a cause of kidney failure; bone thinning (see Osteoporosis); hyperparathyroidism; and anaemia, in which the oxygen-carrying capacity of the blood is reduced.
How is it diagnosed?
If you have symptoms of chronic kidney failure, your doctor will probably arrange for tests of your blood and urine. You may also have ultrasound scanning, radionuclide scanning, or CT scanning to assess the size of the kidneys; abnormally small kidneys are often a sign of chronic kidney failure. In addition, you may need to undergo a kidney biopsy, a procedure in which a small piece of kidney tissue is removed and examined under a microscope to determine the nature of kidney damage.
What is the treatment?
Treatment is directed at the underlying cause. Corticosteroids may be used to treat some forms of glomerulonephritis. Drugs for high blood pressure (see Antihypertensive drugs) may also be given, whether the condition is the cause or result of chronic kidney disease. If there is an obstruction in the urinary tract, you will probably need surgery to relieve it. In addition, your doctor will monitor the progress of the disease and the effectiveness of your treatment with regular checkups.
What is the prognosis?
The outlook for chronic kidney failure depends on the cause and severity of the kidney damage. If your doctor is able to treat the cause and prevent further damage to your kidneys, you may not need dialysis. However, in many cases, treatment only slows the rate of deterioration. After several months or years, chronic kidney failure may develop into end-stage kidney failure, in which the damage is irreversible. At this stage, dialysis or a kidney transplant operation are the only treatment options.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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