Acute kidney failure is the sudden loss of your kidneys' ability to perform their main function — eliminate excess fluid and electrolytes as well as waste material from your blood. When your kidneys lose their filtering ability, dangerous levels of fluid, electrolytes and waste accumulate in your body.

Acute kidney failure is most common in people who are already hospitalized, particularly people who need intensive care. Acute kidney failure tends to occur after complicated surgery, after a severe injury or when blood flow to your kidneys is disrupted.

Acute kidney failure can be serious and generally requires intensive treatment. However, acute kidney failure may be reversible. If you're otherwise in good health, you can recover normal kidney function.