Acute kidney failure happens when human kidneys suddenly lose the ability to eliminate excess fluids, salts and waste materials from one’s blood. This elimination process is the primary function of your kidneys. Acute kidney failure is also known as acute kidney injury or acute renal failure. It is common in patients who are already in the hospital. It might develop rapidly over a few weeks, days or even hours. Patients, who are critically ill, need comprehensive care to cut down the life-threatening risks of acute kidney failure. This condition requires intensive treatment. However, it may be reversible with good treatment.