Authors: Written by the doctors and editors at UpToDate. | Content provided by

Acute kidney injury is when the kidneys suddenly stop working. Normally, the kidneys filter the blood and remove waste and excess salt and water (figure 1). The word "acute" means sudden. Another term for acute kidney injury is "acute kidney failure."

What causes acute kidney injury?

Acute kidney injury can have different causes. It can happen when:

  • Less blood than usual flows to the kidneys. Different things can cause this to happen. For example, in a condition called heart failure, the heart might not be able to pump enough blood to the kidneys.
  • The kidneys get damaged. Some causes of kidney damage are infections, cancer, certain medicines, and some autoimmune conditions. In an autoimmune condition, a person's infection-fighting system attacks their body.
  • The path the urine takes to leave the body is blocked. Some causes of blockages are prostate problems (in men) and cancer. The blockage of urine causes pressure on the kidney, which leads to damage.

Learn More about Acute Renal Failure