Acute renal failure is a sudden loss of kidney function over a few hours or days and is a medical emergency.
The cause is split into three categories, pre-renal, renal and post-renal. Common causes include dehydration, shock, poisoning, infection, and inflammation.
Symptoms include vomiting, lethargy, decreased urination, loss of appetite, weakness, loss of coordination and seizures.
Treatment is aimed at addressing the underlying cause and giving supportive care such as fluid therapy.
What is acute renal failure?
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.
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 a life-threatening condition and a medical emergency. Veterinary attention must be sought immediately.
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.
Acute renal failure occurs as a result of an insult or injury to the kidneys. There are numerous possible causes of acute renal failure in cats. Damage is split into three categories. Pre-renal-not enough blood to the kidneys, Renal-damage to the kidneys, Post renal-blockage.
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.
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 to check to see how concentrated the urine is.
Kidney ultrasound or x-ray.
A kidney biopsy can help determine a definitive underlying cause.
The goal of treatment is to address the specific cause as well as supportive therapy to restore the cat’s fluid, electrolyte, and acid-base balance.
The cornerstone of treatment is fluid therapy to maintain hydration, correct electrolyte imbalances and increase kidney flow and urinary excretion of waste products. Great care must be taken when administering fluids, if the kidneys are not excreting fluids efficiently, they can potentially build up in the body which can lead to pulmonary edema.
If the cat has a urinary blockage, catheterisation to restore urination. Insertion of the catheter will be under sedation.
After the cat has been rehydrated, diuretics such as furosemide to increase urination.
Medications to control nausea and vomiting.
During treatment, hydration, kidney function, acid base and urination will be closely monitored.
Urinary blockage-Catheterisation or surgery to unblock the cat.
Medications-Discontinue any medications which may have caused the problem.
Blood loss-Blood transfusions to replace lost blood.
Poisoning-Induce vomiting or pump the stomach if ingestion occurred within the previous two hours. Activated charcoal to bind to the toxins remaining in the system.