A cat's kidneys perform a broad range of essential functions, including the removal of waste from the bloodstream and the regulation of blood consistency. Unfortunately, the filtering systems inside feline kidneys are susceptible to degeneration over time, as well as to illness or injuries.
Younger cats are more likely to develop acute kidney failure, which presents over the course of days to weeks. It most commonly results following the ingestion of toxic substances, including human medications and pesticides, though it may also be a result of infection or trauma. If acute kidney failure is identified and treated early in its development, damage may be reversible and function returned.
Chronic kidney failure, by contrast, has no known cure. It occurs when scar tissue takes the place of at least 75 percent of working kidney tissue, and it develops over the course of months to years. Veterinary science has not yet identified a single cause for this type of kidney failure, though it may be an end result of such complex conditions as high blood pressure, dental disease, and thyroid dysfunction.