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Acute Renal FailureTopic Overview
Is this topic for you?This topic provides information about sudden kidney failure. If you are looking for information about long-term kidney disease, see the topic Chronic Kidney Disease. What is acute renal failure?Acute renal failure
(also called acute kidney injury) means that your
kidneys What causes acute renal failure?Acute renal failure has three main causes:
You have a greater chance of getting acute renal failure if:
What are the symptoms?Symptoms of acute renal failure may include:
Some people may not have any symptoms. How is acute renal failure diagnosed?Your doctor will ask about symptoms you may have, what medicines you take, and what tests you have had. Your symptoms can help point to the cause of your kidney problem. Blood and urine tests can check how well your kidneys are working. A chemistry screen can show if you have normal levels of sodium (salt), potassium, and calcium. You may also have an ultrasound. This imaging test lets your doctor see your kidneys. If you are already in the hospital, tests done for other problems also may find kidney failure. How is it treated?Your doctor or a kidney specialist (nephrologist) will try to treat the problem that is causing your kidneys to fail. At the same time, the doctor will try to:
You can help yourself heal by taking your medicines as your doctor tells you to. You also may need to follow a special diet to keep your kidneys from working too hard. You may need to limit sodium, potassium, and phosphorus. A dietitian can help you plan meals. Does acute renal failure cause lasting problems?About half the time, doctors can fix the problems that cause kidney failure in a few days or weeks. These people’s kidneys will work well enough for them to live normal lives. But other people may have permanent kidney damage that leads to chronic kidney disease. Older people and those who are very sick from other health problems may not get better. People who die usually do so because of the health problem that caused their kidneys to fail. Frequently Asked Questions
CauseA number of serious conditions or diseases can cause the kidneys to stop working properly. You may develop acute renal failure if:
The three main types of acute renal failure are:
SymptomsAcute renal failure often does not cause symptoms that you notice. If you are already in the hospital, tests done for other problems may also detect your kidney failure. When symptoms do appear, they may include:
The symptoms can help your doctor find out what type of kidney failure is present.
Uremic syndrome (uremia) is a serious complication of severe or prolonged acute renal failure. It can cause severe nausea, confusion, seizures, irregular heart rhythm, and fluid in the lungs (pulmonary edema). What HappensAcute renal failure occurs within hours to days when the kidneys lose their ability to remove waste products and excess fluids from the body. The most common cause of this is reduced blood flow to the kidneys, either from dehydration, surgery, a severe infection, or injury. When blood flow to the kidneys decreases, waste products and excess fluids are not adequately removed from the body. Treatment can usually reverse acute renal failure in a few days or weeks. But in some people it causes permanent kidney damage that leads to chronic kidney disease. A small percentage of them will need to have regular dialysis or a kidney transplant. If acute renal failure is not treated, complications can develop that affect the entire body. These may include:
About half of people who develop acute renal failure recover. And most of those who recover have enough kidney function to live normal lives. Older adults and people who have other serious medical problems are less likely to regain their health. Those who die usually die from the problem that caused their kidney failure, not from the kidney failure itself. What Increases Your RiskYou are more likely to develop acute renal failure if you have certain conditions or diseases, especially if you are an older adult. Conditions that increase your risk include:
Acute renal failure usually occurs in people who are already seriously ill and are in the hospital or intensive care. People who have heart or abdominal surgery or bone marrow transplant have a higher risk. When To Call a DoctorAcute renal failure is usually diagnosed during a hospital stay for another cause. About 30% of people in an intensive care unit (ICU) are diagnosed with acute renal failure.1 Call your doctor immediately if you have not urinated at all in the last 24 hours. Call your doctor to schedule an appointment if you:
Watchful WaitingA wait-and-see approach is not appropriate for acute renal failure. If you have been diagnosed with or could have acute renal failure, you need to be treated. Your doctor will take steps to increase blood flow to your kidneys and support the kidneys until they begin working normally. Who To SeeThe following health professionals can diagnose acute renal failure:
Depending on how bad your acute renal failure is, you may be treated by a nephrologist or an internist. If you are in an intensive care unit (ICU) when renal failure is diagnosed, you will probably be treated by a nephrologist. To prepare for your appointment, see the topic Making the Most of Your Appointment. Exams and TestsYour doctor will begin to evaluate your acute renal failure with a medical history and physical exam. Your doctor will review your health history and hospital chart (if you are currently in the hospital), check all the medicines you are taking, and ask about any other illnesses you have. A complete evaluation is needed to:
Lab testsDoctors routinely use blood and urine tests to evaluate acute renal failure. These tests can detect a buildup of waste products in the blood and chemical imbalances in the body. These tests may help diagnose another disease or infection you have. Blood and urine tests may include:
Imaging testsImaging tests provide pictures of your kidneys. They can help your doctor find out whether kidney failure is acute or chronic and check for a blockage in the urinary tract. The imaging tests most commonly used for these purposes are:
If a blockage is believed to be causing acute renal failure (postrenal acute renal failure), you may need more extensive tests to find out the location and cause of the obstruction. These tests may include the imaging tests listed above, as well as:
Treatment OverviewThe goals of treatment for acute renal failure are to:
Treating the causeBecause treatment for acute renal failure (ARF) depends on what caused it, treatment can vary widely. Your doctor may need to:
Supporting your kidneysSupporting your kidneys when you have acute renal failure can be complicated. Most people who develop acute renal failure are already in a hospital being treated for another medical problem and already may be critically ill before acute renal failure develops. Treating the primary medical problem may make acute renal failure worse. As fluid and waste build up in the blood, acute renal failure can lead to severe, life-threatening complications, such as uremic syndrome (uremia) and infection (sepsis). It is important to control early complications, such as fluid overload, chemical imbalances, and anemia, so that more serious complications are less likely to develop. Support for your kidneys so they can heal will include close management of:
You may need dialysis daily or every other day to support the kidneys until they recover. Dialysis uses a machine to filter wastes and remove extra fluid from the blood. Hemodialysis is the most common treatment for acute renal failure. It does not shorten or reverse acute renal failure, but it controls blood pressure and corrects life-threatening fluid and electrolyte imbalances that occur when the kidneys are not working properly. Before you start dialysis, your doctor will need to create a dialysis access. The access is the site where the dialysis needles can be inserted to send the blood to and from the dialysis machine. For example, you might have a small tube (catheter) placed in a vein in your arm, leg, chest, or neck. The type of access will depend on the type of dialysis you have. RecoveryKidney function may quickly return to normal if the cause of acute renal failure is diagnosed and corrected. Acute renal failure may be corrected within a few days, or it may last for more than a month. Chances of recovery depend on many factors, including what caused the kidneys to fail, how severe the failure was and how long it lasted, how quickly the problem was found and treated, and what other medical conditions you have. For example, acute renal failure caused by dehydration, blood loss, or a blockage in the urinary system often can be reversed quickly without any permanent kidney damage. More than half of people who develop acute renal failure survive. Of those who survive, many have normal kidney function and do not need further treatment. But a few do not regain kidney function and need long-term dialysis or a kidney transplant.1 What To Think AboutPalliative care If your condition gets worse, you may want to think about palliative care. Palliative care is a kind of care for people who have illnesses that do not go away and often get worse over time. It is different than care to cure your illness, called curative treatment. Palliative care focuses on improving your quality of life—not just in your body, but also in your mind and spirit. Some people combine palliative care with curative care. Palliative care may help you manage symptoms or side effects from treatment. It could also help you cope with your feelings about living with a long-term illness, make future plans around your medical care, or help your family better understand your illness and how to support you. If you are interested in palliative care, talk to your doctor. He or she may be able to manage your care or refer you to a doctor who specializes in this type of care. For more information, see the topic Palliative Care. End-of-life issues Acute renal failure is often progressive. After it has developed, you have a greater risk for developing serious problems with infection and heart disease. If you become dependent on dialysis to treat your kidney failure, you may wish to talk to your family and your doctor about health care and other legal issues that arise near the end of life. You may find it helpful and comforting to state your health care choices in writing (with an advance directive such as a living will) while you are still able to make and communicate these decisions. Think about your treatment options and which would be best for you. You may wish to choose a health care agent to make and carry out decisions about your care if you become unable to speak for yourself. For more information, see the topics Writing an Advance Directive, Choosing a Health Care Agent, or Care at the End of Life. A time may come when your goals or the goals of your loved ones may change from treating or curing an illness to maintaining comfort and dignity. Your nephrologist will be able to answer questions about your choices when cure is no longer an option. Hospice services focus on providing care and support to you and your loved ones. Hospice caregivers can help you stay as alert and comfortable as possible in a familiar place with family and friends. For more information, see the topic Hospice Care. PreventionMost cases of acute renal failure occur in people who are already hospitalized for another serious injury or illness. Doctors may be able to prevent kidney failure by identifying patients who are at high risk and by avoiding medicines and other situations that may cause acute renal failure. Diseases that increase your chance of developing kidney failure are diabetes, high blood pressure, heart failure, obesity, and long-term kidney disease (chronic renal insufficiency). If you have any of these conditions, take extra precautions when starting new medicines. Commonly used medicines, such as aspirin and ibuprofen (nonsteroidal anti-inflammatory drugs), can make kidney function worse in people who already have impaired kidney function, diabetes, high blood pressure, or heart failure. If you are in the hospital and have a higher risk for developing acute renal failure because of surgery, another medical condition, or a severe injury, your doctor may take precautions to help you avoid acute renal failure:
Home TreatmentIf you have had acute renal failure (ARF) and your kidneys have not recovered fully, you may need to follow a special diet that keeps your kidneys from having to work too hard. A dietitian will work with you to plan a diet that best fits your needs. Depending on the extent of your kidney damage, other diseases you may have, and whether you are receiving dialysis, you may need to control your intake of minerals (electrolytes) and fluids. You may also have to limit how much protein you eat. In general, you may need to:
Being on dialysis creates some very special needs. It is important to eat the right number of calories and nutrients to stay as healthy as you can. A nutritionist or dietitian can help you design an appropriate meal plan. MedicationsYou may be given medicines to treat the cause of your acute renal failure or to prevent complications. For instance, you may take antibiotics to prevent or treat infections. And you may take other medicines to get rid of extra fluid and prevent electrolyte imbalances, which can be dangerous. Your doctor may adjust the dose of your medicines so that they work well for you. Diuretic medicines, such as Lasix, have traditionally been used to treat acute renal failure, because they quickly increase urine output. But there is not good evidence that diuretics help people with acute renal failure get better.3 Depending on the cause and severity of your acute renal failure, your doctor may choose another method to get rid of extra fluids. SurgeryYour nephrologist may talk to you about kidney transplant for acute renal failure if:
For more information about the issues involved in transplants, see the topic Organ Transplant. Other TreatmentDialysis When acute renal failure develops, you may need dialysis. Dialysis is a mechanical process that performs the work of healthy kidneys by:
Before you start dialysis, your doctor will need to create a dialysis access. The access is the site where the dialysis needles can be inserted to send the blood to and from the dialysis machine. For example, you might have a small tube (catheter) placed in a vein in your arm, leg, chest, or neck. The type of access will depend on the type of dialysis you have. Two types of dialysis may be used to treat acute renal failure:
To measure how well dialysis is working, you will have blood samples drawn before and after dialysis. These will be tested to measure the levels of urea (blood urea nitrogen, or BUN) in your blood. By measuring BUN before and after a dialysis treatment, your doctor can learn how well dialysis has removed wastes from your bloodstream. After severe acute renal failure starts, dialysis is the only way—other than receiving a kidney transplant—to sustain life. Treatment for blockages About 5% of
acute renal failure cases are caused by a blockage in
the
urinary tract that causes waste to build up in the
kidneys If your doctor cannot remove the blockage, he or she may reroute the urine flow around the blockage using a catheter or a stent. Placing a catheter in the bladder to empty it can quickly relieve symptoms and allow kidney function to return to normal. Other Places To Get HelpOrganizations
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