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CRF, chronic kidney failure
Chronic renal failure is a disease in which the kidneys gradually stop working over a period of a few years.
What is going on in the body?
In a healthy body, the kidneys filter waste and other impurities from the blood. In people with chronic renal failure, toxins that the kidneys normally eliminate in urine slowly build up in the body. The most commonly measured of these toxins are urea, a nitrogen waste product, and creatinine. The amount of toxins in the blood roughly indicates how well the kidneys are working.
What are the signs and symptoms of the disease?
Often the buildup of toxins causes no symptoms and this condition is called azotemia. Uremia is a term that is used when stored toxins cause symptoms, including:
What are the causes and risks of the disease?
- increased or decreased urine output depending on the stage of chronic renal failure
- generalised swelling
- poor appetite
- metallic taste
- frequent hiccups
- weight loss
- mental slowness or confusion
- seizures, or sudden, uncontrollable body spasms
- leg cramps
- pale skin colour
A primary kidney disease may cause chronic renal failure. Chronic renal failure may also be due to other diseases that affect kidneys, such as diabetes or high blood pressure. Common causes include:
Everyone is at risk for chronic renal failure as they age. Some people have an increased risk, such as:
- glomerulonephritis, inflammation of the glomerulus, which is the part of the kidney consisting of blood vessels and nerve fibres
- polycystic kidneys, a condition in which the kidneys become enlarged and grow cysts
- interstitial disease, a disease within the structures that support the cells of the kidney
- obstructive uropathy, which is any condition that blocks the flow of urine
- systemic lupus erythematosus, a long-term disease that affects many parts of the body, including the kidneys
- multiple myeloma, or cancer of the bone marrow
What can be done to prevent the disease?
- indigenous Australians
- those who have a family history of the disease
The best ways to slow the progression this disease is to:
How is the disease diagnosed?
- control blood pressure using ACE inhibitors to reduce the protein spillage in urine
- keep blood sugar in good control if a person has diabetes
Although chronic renal failure usually has no symptoms, a physical examination by a doctor is helpful. Since many diseases lead to chronic renal failure, the diagnosis of diseases causing chronic renal failure can vary. There are a few common abnormalities associated with the condition. For instance:
If the underlying kidney disease causing chronic renal failure is unclear, a kidney biopsy may be needed.
- A urinalysis may show protein, red blood cells, or different types of casts, which are structures made when minerals collect on the walls of the kidneys.
- A blood sample may show elevated creatinine and urea, which are both toxins.
- Levels of erythropoietin, a hormone produced by the kidneys, may be low.
- Levels of serum potassium, phosphorous, parathyroid hormone, magnesium and calcium may be high or low.
- Malnourishment can occur.
- Kidneys may be small, and scarred.
What are the long-term effects of the disease?
The long-term effects include:
What are the treatments for the disease?
- progression to end-stage renal disease.
- high blood pressure.
- generalised swelling due to the body's inability to get rid of extra fluids.
- electrolyte disturbances, especially potassium. Electrolytes are compounds or elements that the body needs in order to function.
- anaemia, or low levels of haemoglobin, an oxygen-carrying protein.
- progression or development of heart disease.
- calcium and phosphorous abnormalities, which may lead to many kinds of bone diseases.
- increased susceptibility to infections.
- inability to excrete acids generated from protein digestion.
- irregular periods and decreased sex drive.
Treatment of chronic renal failure includes:
What happens after treatment for the disease?
- eating a protein-, potassium- and phosphorous-restricted diet
- limiting fluids
- controlling blood pressure using high blood pressure drugs
- controlling fluids using diuretics, or water pills
- using erythropoetin injections to improve anaemia
- using phosphate binders, such as calcium carbonate, to decrease absorption of phosphate
- using bicarbonate to improve acid-base status
- haemodialysis, a process in which wastes or impurities are filtered from the blood
- peritoneal dialysis, a filtering procedure that corrects too little or too much electrolytes in the blood
- kidney transplantation, which involves replacing a diseased kidney with a healthy kidney from another person
Most cases of chronic renal failure progress to end-stage renal disease. Dialysis or transplantation is eventually required to treat the symptoms of end-stage renal disease.
How is the disease monitored?
A doctor will usually monitor a person for symptoms of complete kidney failure. Once these symptoms are apparent, dialysis is a next step. Kidney function is also monitored by repeated blood sample and 24-hour urine collection.
Author: Rajnish K. Dhingra, MD
Reviewer: HealthAnswers Australia Medical Review Panel
Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia
Last Updated: 1/10/2001
Potential conflict of interest information for reviewers available on request