What is Acute Kidney Failure?

Your kidneys, like every other organ in your body, have multiple jobs. They’re deeply connected to the rest of your body. Their main function is to filter waste out of your blood. They also remove extra fluid from your blood (this becomes urine) and control blood pressure. Kidneys help make red blood cells. They regulate electrolytes (a type of nutrient) and activate vitamin D, too.

When your kidneys are damaged, they stop working like they should. This could happen because of another health condition, like diabetes. A decrease in kidney function that happens over time is called chronic kidney failure.

When your kidneys stop working suddenly, you have what doctors call acute kidney failure (or acute renal failure). It can happen over just a few hours or days.

Acute kidney failure isn’t always permanent. If you get treatment right away -- and if you don’t have other serious health problems -- your kidneys may go back to working like normal.

Symptoms of Acute Kidney Failure

Sometimes, there aren’t any. Your doctor may discover you have this condition while doing lab tests for another reason.

If you do have symptoms, they’ll depend on how bad your loss of kidney function is, how quickly you lose kidney function, and the reasons for your kidney failure. You may experience the following:

  • Peeing less than normal
  • Swelling in your legs, ankles, and feet (caused by your body holding on to fluid)
  • Drowsiness or feeling very tired
  • Shortness of breath
  • Itching
  • Joint pain, swelling
  • Loss of appetite
  • Confusion
  • Throwing up or feeling like you’re going to
  • Chest pain or pressure
  • Muscle twitching
  • Seizures or coma (in severe cases)
  • Stomach and back pain
  • Fever
  • Rash
  • Nosebleed

Causes of Acute Kidney Failure

There are three main reasons your kidneys fail all of a sudden:

  1. Something is stopping blood flow to your kidneys. It could be because of:
  1. You have a condition that’s blocking urine from leaving your kidneys. This could mean:
  1. Something has directly damaged your kidneys, like:


Am I at Risk for Acute Kidney Failure?

Most of the time, kidney failure happens along with another medical condition or event. If you fall into any of the following categories, you may have a greater chance of acute kidney failure:

  • You’ve been hospitalized for a long time, especially in intensive care.
  • You have diabetes.
  • You’re elderly.
  • You have coronary artery disease.
  • You have heart failure or high blood pressure.
  • You have chronic kidney or liver disease.

How do Doctors Diagnose Kidney Failure?

Your doctor will start with a physical exam. Then, he’ll order tests of your blood, urine, and kidneys.

Blood tests. These measure two substances in your blood -- creatinine and urea nitrogen.

  • Creatinine is a waste product in your blood that’s produced by muscle activity. Normally, it’s removed from your blood by your kidneys. But if those organs stop working, your creatinine level rises.
  • Urea nitrogen is another waste product in your blood. It’s created when protein from the foods you eat is broken down. Like creatinine, your kidneys remove this from your blood. When your kidneys stop working, your urea nitrogen levels rise.

Urine tests. Your doctor will check your pee for blood and protein. He’ll also look for certain electrolytes (chemicals that control important body functions). The results help him understand what’s causing your kidney failure.

Imaging tests. Some tests, like ultrasonography or a CT scan, can show whether your kidneys are enlarged or there’s a blockage in your urine flow. An angiogram can tell your doctor if the arteries or veins that lead to your kidneys are blocked. An MRI can show the same thing.

Kidney Failure Treatment

If there aren’t any other problems, the kidneys may heal themselves.

In most other cases, acute kidney failure can be treated if it’s caught early. It may involve changes to your diet, the use of medications, or even dialysis.

  • Diet. Your doctor will limit the amount of salt and potassium you can take in until your kidneys heal. That’s because both of these substances are removed from your body through your kidneys. Changing how and what you eat won’t reverse acute kidney failure. But your doctor may modify your diet while he deals with the conditions that caused it. This may mean treating a health problem like heart failure, taking you off certain medications, or giving you fluids through an IV if you’re dehydrated.
  • Medications. Your doctor may prescribe medicines that regulate the amount of phosphorous and potassium in your blood. When your kidneys fail, they can’t remove these substances from your body. Medications won’t help your kidneys, but they may reduce some of the problems kidney failure causes.
  • Dialysis . If your kidney damage is severe enough, you may require hemodialysis until your kidneys can heal. Dialysis does not help kidneys heal but takes over the work of kidneys until they do. If your kidneys don't heal, dialysis could be long-term.
WebMD Medical Reference Reviewed by Minesh Khatri, MD on December 23, 2018



American Kidney Fund: “Kidney Failure/ESRD.”

National Institute of Diabetes and Digestive and Kidney Diseases: “Kidney Failure.”

Mayo Clinic: “Acute Kidney Failure.”

National Institute of Diabetes and Digestive and Kidney Diseases: “Kidney Disease: What to Expect.”

Merck Manuals: “Acute Kidney Injury.”

University of New Mexico health Sciences Center: “Electrolyte Imbalance.”

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