KIDNEY FAILURE

also called Renal Failure, partial or complete loss of kidney function. Kidney failure is classified as acute (when the onset is sudden) or chronic. Acute kidney failure results in reduced output of urine, abnormally high levels of nitrogenous substances, potassium, sulfates, and phosphates in the blood, and abnormally low blood levels of sodium, calcium, and carbon dioxide (see uremia). Ordinarily the affected person recovers in six weeks or less. Causes of kidney failure include destruction of the tubules in the kidney by drugs or organic solvents such as carbon tetrachloride, acetone, and ethylene glycol; exposure to compounds of metals such as mercury, lead, and uranium; physical injuries or major surgery causing much loss of blood or an increase in blood pressure; severe burns; and incompatible blood transfusions. Renal failure can also result from diseases that destroy the cortex (outer substance) of the kidney; from severe bacterial infections of the kidney; from diabetes that causes destruction of the medulla (the inner substance) of the kidney; and from overabundance of calcium salts in the kidneys. Blockage of the renal arteries, liver diseases, and obstruction of the urinary tract produce acute failure; on rare occasions, kidney failure can occur without apparent symptoms. Complications that arise from kidney failure include heart failure, pulmonary edema, and an overabundance of potassium in the body. Chronic renal failure is usually the result of prolonged diseases of the kidney. In chronic failure the blood becomes more acidic than normal and there can be loss of calcium from the bones. Nerve degeneration can also occur. Chronically diseased kidneys can sustain life until about 90 percent of their functioning capacity has been lost. When most of the kidney is diseased, the remaining portion increases its activity to compensate for the loss. If one kidney is removed, the other increases in size and function to handle the overload. Treatment when failure of both kidneys occurs usually requires dialysis by means of an artifical kidney machine. In cases of less severe kidney failure, this process allows the kidney tissue time to rest and repair itself. If adequate recovery does not occur, a kidney transplant may be considered.