Renal Failure in Dogs and Cats
Kidney Failure: Explanation of, Symptoms, Diagnosis, and Treatment
What is renal failure? How is it treated? What are the Symptoms? For many pet owners facing a diagnosis of kidney failure, these are common questions.
Renal failure or kidney failure occurs when the kidneys aren’t able to function properly. Kidneys are essentially the body’s filtration system. They are made up of hundreds of thousands of nephrons, which filter out wastes from the blood stream in the form of urine. In addition to this, the kidneys are also responsible for maintaining water and electrolyte balances, and producing some hormones such as erythropoietin, which stimulates red blood cell production.
There are two types of renal failure: acute and chronic. Acute renal failure occurs very quickly as a result of lost function. It can be caused by toxins such as antifreeze, or many poisonous plants. It can also be caused by low blood pressure, a decrease in blood volume, a lack of blood supply to the kidneys, or a urinary blockage. Acute renal failure is potentially reversible, but can become chronic if left untreated.
Chronic renal failure is most commonly seen in older cats, but does also occur in dogs. Because signs of renal failure don’t usually become apparent until 65-70% of kidney function is lost, chronic renal failure has been going on for months or even years. There is no cure for chronic renal failure, and the goal is to slow progression and improve the pet’s quality of life.
Early symptoms of renal failure include: increased thirst and urination because the kidneys are unable to produce concentrated urine. As renal failure progresses and kidney function declines, the kidneys become unable to filter and excrete waste products, which begin to back up into the blood stream. The causes: anorexia, weight loss, vomiting, weakness and lethargy, and foul breath. The pet may also develop oral ulcers, pale gums, a low body temp, a heart murmur and sometimes arrhythmias or an abnormal heart rhythm. Anemia also results from the lack of red blood cells being produced by the body, which further increases symptoms.
Renal failure is diagnosed by symptoms and laboratory testing. Measuring urine’s specific gravity helps the doctor determine if the kidneys are properly concentrating urine. Blood tests are also run looking at BUN and Creatnine levels, which are two products excreted by the kidneys. Elevated levels in the blood, also called azotemia indicate kidneys aren’t functioning properly. A low packed red cell volume indicates anemia.
Treatment of renal disease is aimed at preventing or slowing further kidney damage. This may include hospitalization and intravenous fluids to flush waste products from the blood stream and correct electrolyte abnormalities, and medications to control symptoms such as: vomiting and loss of appetite. If anemia is severe, a blood transfusion may be preformed to boost red blood cell numbers. Many pets are also managed with a special prescription diet low in protein that is specifically designed for patients with kidney disease. Kidney transplants and dialysis is another option becoming more accessible for pets today, but due to the high costs, aren’t practical for most pet owners.
Many dogs and cats with renal failure are successfully managed and live long happy lives. Regular laboratory testing preformed with the yearly vet visit can help to detect early stages of renal failure before they appear, and starting early treatment can help to slow or halt loss of kidney function to improve the pet's quality of life.
