A sudden failure of the kidneys to function. Kidneys are essential to maintain the fluid balance in the body and control the body's chemistry. Kidney failure leads to a buildup of fluid and an increase in waste products in the blood stream. One serious side effect is an elevation in the body's potassium level which can lead to life threatening heart arrhythmias and death. There are many causes of this disorder. Common causes of acute kidney failure include infections, use of dye for CT scans or heart studies, medication reactions, auto immune diseases, severe dehydration, blocked flow of urine.