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This topic provides
information about sudden kidney injury. If you are looking for information
about long-term kidney disease, see the topic
Chronic Kidney Disease.
What is acute kidney injury?
Acute kidney injury
(also called acute renal failure) means that your
kidneys have suddenly stopped working. Your kidneys
remove waste products and help balance water and salt and other minerals (electrolytes) in your blood. When your kidneys stop
working, waste products, fluids, and electrolytes build up in your body. This
can cause problems that can be deadly.
What causes acute kidney injury?
Acute kidney injury has three main causes:
- A sudden, serious drop in blood flow to the kidneys. Heavy blood loss, an injury, or a bad
sepsis can reduce blood flow to the kidneys. Not
enough fluid in the body (dehydration) also can harm the
- Damage from some medicines, poisons, or infections. Most people don't have any kidney problems from taking
medicines. But people who have serious, long-term health problems are more likely
than other people to have a kidney problem from medicines. Examples of medicines that
can sometimes harm the kidneys include:
- Antibiotics, such as gentamicin and
- Pain medicines, such as naproxen and
- Some blood pressure medicines, such as ACE
- The dyes used in some X-ray tests.
- A sudden blockage that stops urine from flowing out of the kidneys. Kidney stones, a tumor, an
injury, or an enlarged prostate gland can cause a blockage.
You have a greater chance of getting acute kidney injury
- You are an older adult.
- You have
a long-term health problem such as kidney or liver disease,
high blood pressure,
heart failure, or
- You are already very ill and are
in the hospital or intensive care (ICU). Heart or belly surgery or a
bone marrow transplant can make you more likely to
have kidney problems.
What are the symptoms?
Symptoms of acute kidney injury may include:
- Little or no urine when you
try to urinate.
- Swelling, especially in your legs and feet.
- Not feeling like eating.
- Nausea and
- Feeling confused, anxious and restless, or
- Pain in the back just below the rib cage. This is called
Some people may not have any symptoms. And for people who are already quite ill, the problem that's causing the kidney injury may be causing other symptoms.
How is acute kidney injury diagnosed?
Acute kidney injury is most often diagnosed during a hospital stay for another cause. If you are already in the hospital, tests done for other problems
may find your kidney problem.
If you're not in the hospital but have symptoms of kidney injury, your doctor
will ask about your symptoms, what medicines you take, and what tests
you have had. Your symptoms can help point to the cause of your kidney
Blood and urine tests can check how well your kidneys are
working. A chemistry screen can show if you have normal levels of
calcium. You may also have an
ultrasound. This imaging test lets your doctor see
a picture of your kidneys.