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Acute Kidney Injury

Medically Reviewed.Last updated on 05/20/2026.

An acute kidney injury (AKI) is when your kidneys suddenly stop working as well as they should. This causes waste products to build up in your blood. A separate condition usually causes an AKI, including conditions that affect blood flow or your ability to pee. Treating an AKI involves treating its cause. A severe AKI may require dialysis.

What Is an Acute Kidney Injury?

Some acute kidney injury symptoms, including changes to peeing habits, feeling very tired, swelling and nausea
An acute kidney injury is when your kidneys suddenly stop working. AKI symptoms may include fatigue, swelling and nausea.

An acute kidney injury (AKI) is when your kidneys abruptly decrease function and stop removing waste products from your blood. “Acute” means it develops suddenly — it can happen over a few hours or over the course of a week. It usually develops as a result of another serious condition.

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An AKI can be mild or severe. Mild cases may not cause permanent damage. But a severe AKI may be fatal without treatment.

Other names for acute kidney injury include:

  • Acute renal injury
  • Acute kidney failure
  • Acute renal failure

“Renal” is another word for kidney.

Symptoms and Causes

Symptoms of an acute kidney injury

Acute kidney injury symptoms may vary according to the cause and severity of your kidney damage. In mild cases, you may not have any symptoms. If you do have symptoms, they may include:

  • Peeing less than usual (oliguria)
  • Swelling, especially in your feet, ankles and legs
  • Tiredness, weakness or low energy levels
  • Itchy skin (pruritus)
  • Nausea and vomiting
  • Diarrhea
  • Confusion
  • Loss of appetite
  • High blood pressure (hypertension)
  • Flank pain
  • Chest pain

Causes

There are many different possible causes of an acute kidney injury. These may include:

  • Reduced blood flow to the kidneys
  • Problems with the kidney itself
  • Urinary obstructions
  • Medications or other substances

Reduced blood flow to the kidneys

Conditions that may reduce blood flow to your kidneys include:

  • Dehydration
  • Low fluid volume in your body (hypovolemia)
  • Heart attack
  • Heart failure, including congestive heart failure and acute heart failure
  • Severe blood loss (hemorrhage)
  • Severe burns
  • Low blood pressure (hypotension)
  • Severe bacterial infections

Problems with the kidney itself

Conditions that affect your kidneys and may cause damage include:

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Urinary obstructions

Common urinary obstructions that may cause obstructions include:

  • Kidney stones
  • Enlarged prostate (benign prostatic hyperplasia)
  • Cervical cancer
  • Bladder cancer
  • Prostate cancer
  • Colorectal (colon) cancer
  • Blood clots in your urinary system

Medications or other substances

Sometimes medications or other substances may contribute to a kidney injury. But they may not be the main cause. Your risk of AKI increases if you have reduced blood flow to your kidneys, kidney damage or a urinary obstruction and use some of the following medications or substances:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Certain antibiotics
  • Blood pressure medications (antihypertensives), including ACE inhibitors, ARBs and diuretics
  • Medications that treat cancer or HIV
  • Ingesting toxic alcohols, including rubbing alcohol (isopropyl/isopropanol), antifreeze (ethylene glycol) and methanol
  • Heroin
  • Cocaine

Who does it affect?

You’re at a greater risk of developing an acute kidney injury if you:

  • Are 65 or older
  • Have chronic kidney disease (CKD)
  • Have diabetes
  • Have high blood pressure
  • Are dehydrated
  • Have a severe bacterial infection or response to an infection (sepsis)
  • Have a blockage in your urinary system
  • Take medications or substances that increase your risk of kidney damage

Diagnosis and Tests

How is an acute kidney injury diagnosed?

A healthcare provider will:

  • Review your medical history
  • Ask about your symptoms and any over-the-counter medications you take, including herbal supplements
  • Perform a physical exam

If they suspect an acute kidney injury, they’ll recommend tests to help confirm their diagnosis.

What tests will be done to diagnose it?

A healthcare provider may recommend different types of tests to diagnose an acute kidney injury, including:

  • Blood tests, including creatinine clearance test, blood urea nitrogen (BUN) and estimated glomerular filtration rate (eGFR)
  • Pee test (urinalysis)
  • Imaging tests, including an ultrasound

In rare cases, a provider may recommend a kidney biopsy.

Management and Treatment

How is an acute kidney injury treated?

Acute kidney injury treatment depends on the underlying cause and its severity. Depending on the cause, a healthcare provider may recommend:

  • Treating dehydration by drinking more water or sports drinks (electrolyte drinks) or receiving IV fluids, usually through a vein in your arm
  • Stopping any medications that may be affecting your kidneys
  • Antibiotics to treat an infection
  • Potassium binders or phosphate binders if your kidneys can’t filter potassium or phosphate
  • A urinary catheter to drain pee from your urinary bladder

If a lot of waste products build up in your blood, you may need temporary dialysis. As soon as your kidneys recover, you can usually stop dialysis.

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Is it reversible?

With a proper diagnosis of the cause and prompt treatment, the damage is often reversible. It depends on the underlying cause of your acute kidney injury, the severity of kidney damage and your overall health. A healthcare provider can give you a better idea of what to expect.

How long does it take for an acute kidney injury to heal?

With appropriate treatment, a mild AKI may heal within a few days. Severe cases may take at least two to three weeks or even longer. But if you had kidney problems before an AKI, your kidneys may not fully heal.

How soon after treatment will I feel better?

You’ll likely feel tired or weak after treatment for an acute kidney injury. Your body is unique, and your recovery time may be different from others. It may take you up to a few weeks before you start to feel better. A healthcare provider will give you a better idea of what to expect.

When should I see a healthcare provider?

It’s a good idea to schedule regular or annual appointments with your healthcare provider after an acute kidney injury, even if you make a full recovery. They’ll perform standard tests to make sure your kidneys are functioning as expected. They’ll also let you know what symptoms to be aware of to help prevent another AKI in the future.

Go to the emergency room if you have several of the following symptoms:

  • Feel really tired
  • Aren’t peeing as much as you think you should
  • Aren’t hungry
  • Can’t focus or have trouble sleeping
  • Have swelling around your feet or ankles

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Outlook / Prognosis

What is the prognosis after AKI?

With proper diagnosis and treatment, the outlook (prognosis) for an acute kidney injury is good. Your outlook is usually better if a condition that reduces blood flow to your kidneys causes an AKI. That’s because those conditions are usually treatable. The outlook is worse if an AKI relates to or occurs alongside organ failure.

What is the life expectancy?

It depends on the severity of your acute kidney injury and its cause. In general, your life expectancy is better if you have a mild AKI and get proper treatment quickly. But your life expectancy may be lower if you have an AKI alongside other serious health conditions, such as organ failure. A healthcare provider can best let you know what you may expect.

Prevention

Can an acute kidney injury be prevented?

You can help prevent an acute kidney injury by scheduling annual physical exams with a primary care physician. They’ll monitor your overall health and any conditions that may put you at risk of an AKI.

You can also help prevent an AKI by:

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A note from Cleveland Clinic

It can be a shock to hear that something is affecting your kidneys. But it’s important that you give yourself some time to process and learn about your acute kidney injury (AKI), including what you can do to preserve kidney function. Knowing what caused your AKI, the severity and your treatment options can help calm your mind. Healthcare providers understand what you’re feeling. They’re available to answer any of your questions.

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Medically Reviewed.Last updated on 05/20/2026.

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References

Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.

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If you have a condition that’s affecting your kidneys, you want experts by your side. At Cleveland Clinic, we’ll work with you to craft a personalized treatment plan.

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