Acute renal failure is the sudden, severe impairment of the functioning of the kidneys. The kidneys remove wastes from the blood and also balance water, salt, and electrolytes in the body. Acute renal failure therefore results in a buildup of waste products in the blood and imbalances in water, salt and electrolytes. It is a very serious condition, which could be fatal if not treated. However, treatments exist, including replacements either of kidney functioning (dialysis) or of the kidney itself, so that fatalities from acute renal failure are actually rare.

Causes

Acute renal failure can result from a loss of blood flow to the kidneys. This can occur due to severe blood loss (which also has other health hazards, of course, and can cause death directly) due most often to physical injury, external or internal. It can also result from severe dehydration, injury to the kidneys themselves, or a severe infection. Some medicines, and also some poisons, can also cause renal failure,
although normally some complicating factor must be present for medications to cause kidney failure when used properly.

Medications that can sometimes cause renal failure include certain antibiotics (streptomycin, gentamicin), analgesics (aspirin, ibuprofen), some blood-pressure medications (ACE inhibitors), and the dyes used in X-ray procedures. Finally, acute renal failure can also be caused by a blockage of urine from leaving the kidneys, as by a large kidney stone, a tumor, or an enlarged prostate gland.

Risk Factors

Some of the factors increasing the risk of acute renal failure are old age, diabetes, high blood pressure, obesity, heart disease, and chronic kidney or liver disease.

Symptoms


Symptoms of acute renal failure include little or no urine on urination, loss of appetite, nausea, vomiting, swelling of the legs and feet, pain in the lower back, and feelings of confusion, anxiety, or restlessness.

The most common way for acute renal failure to be diagnosed is during a hospital visit – the complications of the disease are quite severe and often require hospitalization. Blood and urine tests can identify problems with the kidneys.

One important test is a chemistry screen to determine levels of minerals in the blood, including sodium, potassium, and calcium, all of which will be elevated as a result of kidney failure. Medical imaging such as an ultrasound may also be used to identify physical damage to the kidneys and some other problems.

Prognosis

The treatment for acute renal failure depends on what is causing the kidneys to fail, and so does prognosis. On the whole, about half of patients with acute renal failure recover full kidney function with treatment. For others, damage to the kidneys results in chronic renal disease which requires lifestyle adjustment. For a few patients, damage to the kidneys is sufficient and sufficiently irreversible to require a kidney transplant.

Treatment may include dietary and other lifestyle changes, especially reduction in the intake of sodium, potassium, and phosphorus. Surgery may be used to correct blood and urinary flow problems, or medications to treat infections or other contributory problems. Dialysis may be used to replace kidney function, which will alleviate many of the symptoms temporarily. Regular dialysis may be used in the case of irreversible renal failure until a transplant becomes available.

Acute renal failure is seldom fatal if treated, although the underlying medical condition may be (bleeding to death, for example). If untreated, the buildup of wastes in the blood can lead to toxic reactions which can be fatal eventually, and can cause damage to other organs short of  death.