Definition Acute renal failure occurs when the filtering function of the kidneys deteriorate suddenly. The kidneys are not able to maintain normal body function.
What is going on in the body? The kidneys filter the blood in the body and produce urine. They clear the body of many drugs and toxins. They also produce hormones and control blood pressure. The blood to each kidney is supplied by a large artery. Blood flow to the kidneys is crucial both for kidney health and to allow the kidneys to perform their functions of cleaning and maintaining the blood. Anything that leads to a sudden drop in blood flow to the kidneys can cause acute renal failure. When this happens, all of the normal functions of the kidneys can be altered or destroyed.
What are the signs and symptoms of the disease? At first there are no specific signs or symptoms of acute renal failure. But, as the disease progresses many people have decreased urine output. As a result, fluid builds up in the body tissues and organs, such as the lungs. Excessive fluid in the lung spaces leads to shortness of breath and decreased oxygen levels. Fluid may also accumulate in the legs or abdomen. As certain electrolyte imbalances occur, heart arrhythmias can occur. This can lead to palpitations or an irregular heartbeat. In very severe cases, the brain is affected. This can lead to changes in mental status or a person may even go into a coma.
What are the causes and risks of the disease? The following can lead to acute renal failure:
significant loss of blood or sudden drop in blood flow to the kidneys
exposure to toxic substances
exposure to certain drugs
a blockage of urine flow out of the kidneys and into the bladder
Kidneys that have pre-existing disease or damage are at higher risk for acute renal failure.
What can be done to prevent the disease? Acute renal failure cannot always be prevented. One way to prevent it is to avoid situations that lead to a drop in blood flow to the kidneys. Also, drugs that can damage the kidneys should be avoided. Persons with pre-existing kidney disease need to be very careful to avoid certain drugs that are known to affect kidney function.
How is the disease diagnosed? Acute renal failure is diagnosed based on blood tests and urine studies. Blood tests show elevated levels of substances known as urea and creatinine. Levels of electrolytes, such as potassium, are also high. Ultrasound imaging of the kidneys can also help pinpoint the cause of the disorder.
What are the long-term effects of the disease? Most cases of acute renal failure will resolve with supportive therapy. This disease does not necessarily place the person at risk for long-term kidney damage. However, a person who has underlying kidney disease may not recover adequate kidney function. Sometimes a person can develop progressive kidney damage as a result of acute renal failure and require long-term dialysis therapy.
What are the risks to others? This disease is not contagious and does not put other persons at risk.
What are the treatments for the disease? The treatment of acute renal failure is aimed at improving fluid status, electrolyte imbalances, and to support the person during this acute crisis. Close attention is paid to a fluid balance. Certain medications known as diuretics (water pills) can be used to help promote excretion of fluid by the kidneys. In other situations, fluids are given to promote increased blood flow to the kidneys. In situations where blood loss or shock has occurred, blood transfusions may be given. Electrolyte imbalances are monitored closely. Medications can be given to lower elevated electrolytes or potassium levels. Dialysis may be used to replace the normal kidney function until the acute renal failure resolves. Dialysis involves redirecting blood flow from the person to a dialysis machine. The machine filters the blood and then returns it to the person.
What are the side effects of the treatments? Generally, there are few side effects to treatment of acute renal failure. The complexity of the disease itself can lead to further difficulties. When dialysis is necessary, a large intravenous catheter is placed into a vein in the upper arm or chest. A catheter is a tube used for withdrawing and/or adding fluids into the body. This can pose risks of bleeding or infection.
What happens after treatment for the disease? After normal kidney function has returned, the person will be monitored for overall kidney and electrolyte function.
How is the disease monitored? The disease is monitored in the hospital setting.
Author: Bill Harrison, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
