What is acute renal failure?

Acute renal failure (ARF) is the sudden loss of kidney function. It occurs when the kidneys stop working over a period of hours, days, or in some cases, weeks. When ARF occurs, waste products, such as nitrogen, and excess fluids are not removed by the kidneys and build up in the body, upsetting the body's normal chemical balance. Chemicals and electrolytes, such as sodium, potassium, and calcium, which are needed for normal body functioning, become poisonous (toxic) to the body when they reach abnormally high levels.

What causes acute renal failure?

Many conditions, diseases, and medications can cause acute renal failure. The most common causes are dehydration, blood loss from major surgery or injury, or medications, such as contrast agents used in X-ray tests, nonsteroidal anti-inflammatory drugs (NSAIDs), and aminoglycoside antibiotics such as gentamicin. There are three main types of acute renal failure:

• Prerenal ARF is caused by decreased blood supply to the kidneys and accounts for 55% to 60% of all acute renal failure cases.
• Intrinsic or intrarenal ARF results from direct damage to the kidneys and accounts for 35% to 40% of acute renal failure cases.
• Postrenal ARF is caused by blockage of the urinary tract and accounts for about 5% of acute renal failure cases. An obstruction in the urinary tract may cause urine to build up in the kidneys and prevent the flow of urine out of the kidneys.

What are the symptoms of acute renal failure?

Symptoms of acute renal failure depend on the cause of the problem. Symptoms may include:

• Swelling of the hands, face, or feet.
• Decreased urinary output (oliguria).
• Shortness of breath (dyspnea).
• Rapid, irregular heart rate.
• Enlarged or distended neck veins.
• Nausea, vomiting, and loss of appetite.
• Profound weakness or fatigue.
• Confusion, agitation, or combative behavior.

Who is affected by acute renal failure?

Acute renal failure (ARF) occurs most often in people who are already hospitalized for other medical conditions. ARF develops in from 5% to 7% of all patients in the hospital. Of those hospitalized in intensive or critical care units, up to 30% develop ARF. Factors that increase a person's risk of acute renal failure include advanced age, chronic renal insufficiency, liver disease, diabetes, high blood pressure, heart failure, and obesity. People having heart surgery and abdominal surgery also have an increased risk.

How is acute renal failure diagnosed?

Acute renal failure is usually diagnosed using blood and urine tests to monitor kidney function. Tests may include blood urea nitrogen (BUN), serum creatinine, complete blood count (CBC), and a urinalysis. A chemistry screen may be used to look for abnormalities in electrolytes, such as sodium, potassium, and calcium.

How is acute renal failure treated?

The treatment of acute renal failure depends on the cause and may include:

• Correcting the underlying cause of kidney failure, such as dehydration or medication toxicity. Providing supportive care for the kidneys through dialysis.
• Preventing other complications, such as infection or fluid or electrolyte imbalances.

What are the complications of acute renal failure?

• The complications of acute renal failure (ARF) can affect the entire body, including the digestive system, heart, lungs, and nervous system.
• Infection is one of the most common complications of ARF, because the body's immune system may stop working properly.
• Uremic syndrome (uremia) is a serious complication of severe or prolonged acute renal failure. It can cause severe nausea, confusion, psychosis, irregular heart rhythm, and pulmonary edema.
• Increased potassium in the blood.

What is my prognosis if I am diagnosed with acute renal failure?

Acute renal failure (ARF) can usually be reversed, but it can also cause permanent loss of kidney function leading to chronic kidney disease (CKD). Older adults and people who have other serious medical conditions are less likely to recover from ARF and its complications. Approximately 50% of people who develop ARF die from the disease.