Definition of Acute Renal Failure
Kidney failure, also called renal failure, is the inability of the kidneys to filter waste products out of the blood. Normal kidneys remove nitrogen and other wastes from circulation so that they can be excreted in urine. When the kidneys don’t work properly, toxic wastes build up in the dog’s blood. Acute renal failure (ARF) happens when there is some sudden and severe insult to the kidneys. Toxins which normally are filtered out of the dog’s system by its functional kidneys accumulate in the bloodstream, causing imbalances in bodily fluids. The main waste product that builds up in dogs with ARF is blood urea nitrogen (BUN). A dog’s kidneys are especially vulnerable to being damaged by toxins, because about 25% of its blood passes through the kidneys with each heartbeat, and the kidneys are highly sensitized to circulating toxins.