A condition in which the kidneys suddenly can't filter waste from the blood. Acute renal failure develops rapidly over a few hours or days. It may be fatal. It's most common in those who are critically ill and already hospitalized.

Symptoms include decreased urinary output, swelling due to fluid retention, nausea, fatigue and shortness of breath. Sometimes symptoms may be subtle or may not appear at all.

In addition to addressing the underlying cause, treatments include fluids, medication and dialysis.

Acute kidney failure happens when your kidneys suddenly lose the ability to eliminate excess salts, fluids, and waste materials from the blood. This elimination is the core of your kidneys' main function. Body fluids can rise to dangerous levels when kidneys lose their filtering ability.