Acute renal failure is the inability of the kidneys to filter waste products and toxins from the blood. It has a rapid onset and leads to dangerously high levels of toxins and other metabolic wastes in the bloodstream.
Dehydration and electrolyte imbalances develop. Acute renal failure may be reversed if diagnosed and treated early and aggressively.
Diagnosis is made once a complete history, including signs and symptoms, is obtained. Lab tests are performed to evaluate kidney function and waste product levels. X-rays or ultrasound exam may be performed.
Signs and Symptoms of Acute Renal Failure
The signs and symptoms of renal failure are loss of appetite, listlessness, vomiting and diarrhea, a smell of ammonia on the breath or seizures. Bleeding in the intestinal track may be evidenced by the appearance of blood in vomit or diarrhea. Frequent urination with accidents within the home may occur. In late stages, cats may produce little or no urine. Examination by the veterinarian will show enlarged kidneys. Frequently cats are in shock due to dehydration when arriving at the clinic.
Causes of Acute Renal Failure
There are many causes responsible for the development of acute renal failure.
- Kidney stones causing obstruction
- Antifreeze poisoning
- Toxic plant ingestion
- Rat poison ingestion
- Shock due to blood loss or dehydration
- Congestive heart failure resulting in decreased blood flow to the kidneys
- Low blood pressure
- Blood clots
- Antibiotics that may damage kidney tissue
- Snake or insect bites with envenomation
- Exposure or ingestion of lead, mercury, arsenic or thallium
- Bacterial infection of the kidney
- Feline Infectious Peritonitis
Treatment Options in Acute Renal Failure
Removal or correction of any underlying causes is the primary focus initially. Correcting fluid and electrolyte imbalances is initiated immediately. Kidney function and blood chemistries will be monitored regularly to evaluate and guide treatment decisions.
- Fluid therapy is performed intravenously for the first 1-3 days to correct dehydration. Fluid needs will vary for each cat.
- Dietary changes will be made to help manage fluid retention and control the amount of waste products produced during the digestive process. Reducing salt intake decreases swelling and high blood pressure. Cats with renal failure should be fed foods with low levels of protein, while assuring a high quality. This reduces the amount of nitrogen that the kidneys must filter. Phosphorus intake is restricted and phosphorus binding medications may be prescribed. Specially formulated foods are available, but may not meet the needs of every cat Fresh water needs to be readily available at all times to avoid dehydration due to the large amount of urine produced.
- Removal of excess toxins may be accomplished through dialysis. This treatment mimics the function of the kidneys by filtering the blood. This is most often used in the event of poisoning or other short-term problems and is not readily available in all areas.
- As with humans, when kidney failure is irreversible and terminal, transplant may be considered. Very few centers perform this procedure and the cat will need medications to prevent rejection of the transplanted organ.