Acute kidney failure occurs when the kidneys suddenly become unable to filter waste products from your blood. When kidneys lose their filtering ability, dangerous levels of wastes may accumulate, and your blood’s chemical makeup may get out of balance.
Acute kidney failure — also called acute kidney injury — develops rapidly, usually in less than a few days. Acute kidney failure is most common in people who are already hospitalized, particularly in critically ill people who need intensive care.
Acute kidney failure can be fatal and requires intensive treatment. However, acute kidney failure may be reversible. If you’re in good health, you may recover normal or nearly normal kidney function.
Symptoms of acute kidney failure
Signs and symptoms of acute kidney failure include:
- Decreased urine output, although occasionally urine output remains normal
- Fluid retention, causing swelling in legs, ankles or feet
- Shortness of breath
- Irregular heartbeat
- Chest pain or pressure
- Seizures or coma in severe cases
Sometimes acute kidney failure causes no signs or symptoms and is detected through lab tests done for another reason.
When do you need to see a doctor?
Go to see a doctor immediately or seek emergency care if you have signs or symptoms of acute kidney failure.
Causes of acute kidney failure
Acute kidney failure can occur when:
- You have a medical condition that slows blood flow to kidneys
- You experience direct damage to your kidneys
- The kidneys’ urine drainage tubes (ureters) become blocked and wastes can’t leave your body through urine
Impaired blood flow to the kidneys
Diseases and conditions that may slow blood flow to the kidneys and lead to kidney injury include:
- Blood or fluid loss
- Blood pressure medications
- Heart attack
- Heart disease
- Liver failure
- Use of aspirin, ibuprofen, naproxen sodium or related drugs
- Severe allergic reaction (anaphylaxis)
- Severe burns
- Severe dehydration
Damage to the kidneys
These diseases and agents may damage the kidneys and lead to acute kidney failure:
- Blood clots in the veins and arteries in and around the kidneys
- Cholesterol deposits that block blood flow in the kidneys
- Glomerulonephritis – inflammation of the tiny filters in the kidneys (glomeruli)
- Hemolytic uremic syndrome – a condition that results from premature destruction of red blood cells
- Infection, such as with the virus that causes coronavirus disease 2019 (COVID-19)
- Lupus, an immune system disorder causing glomerulonephritis
- Medications, such as certain chemotherapy drugs, antibiotics and dyes used during imaging tests
- Scleroderma – a group of rare diseases affecting the skin and connective tissues
- Thrombotic thrombocytopenic purpura – a rare blood disorder
- Toxins, such as alcohol, heavy metals and cocaine
- Muscle tissue breakdown (rhabdomyolysis) that leads to kidney damage caused by toxins from muscle tissue destruction
- Breakdown of tumor cells (tumor lysis syndrome), which leads to the release of toxins that can cause kidney injury
Urine blockage in the kidneys
Diseases and medical conditions that block the passage of urine out of the body (urinary obstructions) and can lead to acute kidney injury include:
- Bladder cancer
- Blood clots in the urinary tract
- Cervical cancer
- Colon cancer
- Enlarged prostate
- Kidney stones
- Nerve damage involving the nerves that control the bladder
- Prostate cancer
Acute kidney failure almost always occurs in connection with another medical condition or event. Medical conditions that can increase risk of developing acute kidney failure include:
- Being hospitalized, especially for a serious medical condition that requires intensive care
- Advanced age
- Blockages in the blood vessels in arms or legs (peripheral artery disease)
- High blood pressure
- Heart failure
- Kidney diseases
- Liver diseases
- Certain cancers and their treatments
Complications of acute kidney failure
Complications of acute kidney failure include:
- Fluid buildup. Acute kidney failure may lead to a buildup of fluid in your lungs, which can cause shortness of breath.
- Chest pain. If the lining that covers your heart (pericardium) becomes inflamed, you may experience chest pain.
- Muscle weakness. When the body’s fluids and electrolytes are out of balance, muscle weakness can result.
- Permanent kidney damage. Occasionally, acute kidney failure causes permanent loss of kidney function, or end-stage renal disease. People with end-stage renal disease require either permanent dialysis — a mechanical filtration process used to remove toxins and wastes from the body — or a kidney transplant to survive.
- Death. Acute kidney failure can lead to loss of kidney function and, ultimately, death.
Prevention of acute kidney failure
Acute kidney failure is often difficult to predict or prevent. But you may reduce your risk by taking care of kidneys. Perform the following activities:
- Pay attention to labels when taking over-the-counter pain medications. Follow the instructions for pain medications, such as aspirin, acetaminophen, ibuprofen, and naproxen sodium. Taking too much of these medications may increase risk of kidney injury. This is especially true if you have pre-existing kidney disease, diabetes or high blood pressure.
- Work with your doctor to manage kidney disease and other chronic medical conditions. If you have kidney disease or another medical condition that increases risk of acute kidney failure, such as diabetes or high blood pressure, follow the treatment plan and your doctor’s recommendations to manage your disease.
- Make a healthy lifestyle a priority. Be physically active; eat a sensible, balanced diet; and drink alcohol only in moderation.
Diagnosis of acute kidney failure
If signs and symptoms suggest that you have acute kidney failure, the doctor may recommend certain tests and procedures to verify diagnosis. These tests may include:
- Urine output measurements. Measuring how much you urinate in 24 hours may help your doctor determine the cause of your kidney failure.
- Urine tests. Analyzing a sample of your urine (urinalysis) may reveal abnormalities that suggest kidney failure.
- Blood tests. A sample of your blood may reveal rapidly rising levels of urea and creatinine — two substances used to measure kidney function.
- Imaging tests. Imaging tests such as ultrasound and computerized tomography may be used to help your doctor see your kidneys.
- Removing a sample of kidney tissue for testing. In some situations, your doctor may recommend a kidney biopsy to remove a small sample of kidney tissue for lab testing. Your doctor inserts a needle through your skin and into your kidney to remove the sample.
Treatment of acute kidney failure
Treatment for acute kidney failure typically requires a hospital stay. Most people with acute kidney failure are already hospitalized. How long you’ll stay in the hospital depends on the reason for acute kidney failure and how quickly your kidneys recover.
In some cases, you may be able to recover at home.
Treating the underlying cause of kidney injury
Treatment for acute kidney failure involves identifying the disease or injury that originally damaged kidneys. Treatment options depend on what’s causing kidney failure.
Treating complications until kidneys recover
Doctor will also work to prevent complications and allow your kidneys time to heal. Treatments that help prevent complications include:
- Treatments to balance the amount of fluids in blood. If acute kidney failure is caused by a lack of fluids in your blood, doctor may recommend intravenous fluids. In other cases, acute kidney failure may cause you to have too much fluid, leading to swelling in arms and legs. In these cases, doctor may recommend medications (diuretics) to cause your body to expel extra fluids.
- Medications to control blood potassium. If your kidneys aren’t properly filtering potassium from blood, doctor may prescribe calcium, glucose or sodium polystyrene sulfonate (Kionex) to prevent the accumulation of high levels of potassium in your blood. Too much potassium in the blood can cause dangerous irregular heartbeats (arrhythmias) and muscle weakness.
- Medications to restore blood calcium levels. If the levels of calcium in your blood drop too low, doctor may recommend an infusion of calcium.
- Dialysis to remove toxins from blood. If toxins build up in blood, you may need temporary hemodialysis to help remove toxins and excess fluids from body while your kidneys heal. Dialysis may also help remove excess potassium from your body. During dialysis, a machine pumps blood out of your body through an artificial kidney (dialyzer) that filters out waste. The blood is then returned to your body.
Care at home
During your recovery from acute kidney failure, your doctor may recommend a special diet to support kidneys and limit the work kidneys must do. Doctor may refer you to a dietitian who can analyze your current diet and suggest ways to make your diet easier on your kidneys.
Depending on your situation, dietitian may recommend that you do the following activities:
- Choose lower potassium foods. Dietitian may recommend that you choose lower potassium foods. High-potassium foods include bananas, oranges, potatoes, spinach and tomatoes. Examples of low-potassium foods include apples, cauliflower, peppers, grapes and strawberries.
- Avoid products with added salt. Lower the amount of sodium you eat each day by avoiding products with added salt, including many convenience foods, such as frozen dinners, canned soups and fast foods. Other foods with added salt include salty snack foods, canned vegetables, and processed meats and cheeses.
- Limit phosphorus. Phosphorus is a mineral found in foods, such as whole-grain bread, oatmeal, bran cereals, dark-colored colas, nuts and peanut butter. Too much phosphorus in blood can weaken your bones and cause skin itchiness. Dietitian can give you specific recommendations on phosphorus and how to limit it in your particular situation.
As your kidneys recover, you may no longer need to eat a special diet, although healthy eating remains important.