Renal failure describes a decline in kidney function whereby the kidneys are no longer capable of filtering nitrogenous waste from the bloodstream. Nitrogenous waste is the toxic bi-product that results from normal daily metabolism. Many diverse processes and diseases can cause renal failure. Among the many causes of renal failure are old age, poisons like anti-freeze, rapid blood loss, shock, trauma, severe dehydration, and diseases that obstruct the free flow of urine like feline urological syndrome.

Physical examinations can sometimes diagnosis bladder stones that can obstruct urine flow. Blood tests and urinalysis can reveal how seriously the kidneys are failing to filter and remove waste from the blood. Radiographs of the abdomen can sometimes show causes of renal failure, helping to establish a prognosis. Fluid therapy along with antibiotics and special diets can help increase *Animal*’s quality of life and prolong the life span in renal failure patients.