What is acute renal failure?
Each kidney has tiny filtering units called nephrons. Blood passes through the kidney and is filtered by the nephrons. They reabsorb what is needed and the waste is excreted in the urine. The wastes come from the normal breakdown of active muscle from the food the cat eats.
The body uses the food for energy and self-repair. After the body has taken what it needs from the food, waste is sent to the blood and transported to the kidneys. The kidneys are an amazing organ and even with the loss of some nephrons, the remaining ones can compensate. Kidney disease becomes apparent when 70% of the kidney function has been lost. Once this happens, the kidneys are unable to remove the waste from the body and therefore these wastes build up in the cat causing poisoning.
Acute renal failure is the rapid loss of kidney function resulting in the retention of waste products which would usually be filtered by the kidneys and excreted in the urine. They also lose their ability to concentrate urine and cause electrolyte imbalances.
Acute renal failure is a life-threatening condition and a medical emergency. Veterinary attention must be sought immediately.
Alternative Names: Renal failure - acute, Kidney failure, Kidney failure - acute, Renal failure, ARF.
What do the kidneys do?
Kidneys help control blood pressure by releasing an enzyme called renin. When blood pressure drops and kidneys don’t receive enough blood, renin is released: causing blood vessels to contract (tighten). When blood vessels contract, blood pressure goes up. Acute kidney disease is a sudden decline in kidney function.
Kidneys filter waste products and excess water from the blood. The cleaned blood stays in the body and the waste products leave the body in urine.
Stimulation of red blood cell production.
They help maintain the proper balance of acid and minerals, including sodium, calcium, potassium, and magnesium, in the blood.
What causes acute renal failure in cats?
There are numerous possible causes of acute renal failure in cats, some of which are:
What are the symptoms of acute renal failure in cats?
How is acute renal failure in cats diagnosed?
Your veterinarian will require information on your cat's history, including any possible exposure to poisons and medications it may have ingested (either accidental or as a result of medical treatment for a pre-existing condition), and information on previous illnesses. He will perform a complete physical examination of your cat.
Biochemical profile: Elevated blood urea nitrogen (BUN) and creatinine are both indicative of renal failure.
A complete blood count will be able to provide information on any inflammation or infections your cat may have.
Urinalysis will be able to provide additional information on the extent of kidney damage, urine-concentrating ability and if an infection is present in the urinary tract. 
Urine specific gravity: This test is to check to see how concentrated the urine is.
Kidney ultrasound or x-ray.
A kidney biopsy can help determine a definitive underlying cause.
How is acute renal failure in cats treated?
Prognosis depends on the cause of acute kidney failure and the speed in which it is diagnosed and treated.
Correct or treat the underlying cause of acute kidney failure.
Discontinue any medications which may have causes the problem.
Remove blockage in the urinary tract.
Correct contributing factors such as hypertension.
Administration of fluids to treat dehydration and electrolyte imbalances.
Anti-nausea medication if necessary.
Phosphorus binders may be given. These come in tablet or capsule form.
High blood pressure (hypertension): Medication may be prescribed if your cat's blood pressure is too high.
Please read our article on lily poisoning in cats, which is a common cause of acute renal failure.
 The Cornell Book of Cats.