Acute and chronic renal failure in cats

Akute und chronische Niereninsuffizienz bei Katzen

Symptoms and characteristics of (chronic) renal insufficiency in cats

Chronic renal insufficiency (CRF) in cats is a slowly progressive disease of older cats that usually goes undetected. The functional bodies (nephrons) of the kidneys gradually stop working. The remaining nephrons try to absorb the loss and also lose their functionality due to overload. Symptoms of the disease usually only appear when 75% of kidney capacity has already failed. A consequence of this is a reduced ability to concentrate urine and thus dehydration. The amount the cat drinks increases. This is one of the first symptoms that pet owners notice.

Another task of the kidneys is to return the substances that are important for the body's metabolism from the urine back into the body and to excrete the substances that have to be excreted in the urine. In the disease, necessary proteins are excreted in the urine. The body has to break down the proteins from the muscle mass to maintain a functioning metabolism. Here the owner usually notices that the cat is losing body mass/weight.

On the other hand, the waste products from the protein metabolism can be less and less filtered out of the blood and accumulate there. The cat often feels uncomfortable and as the disease progresses it can lead to frequent vomiting.

Urea, one of the most important waste products, can irritate and damage the mucous membranes, causing injuries and thus pain in the mouth. This and a sense of taste altered by urea causes the cat to refuse the food.

The kidneys also have an influence on blood pressure regulation and the formation of the red blood pigment. Most cats with advanced kidney failure have high blood pressure and later anemia. The increased blood pressure puts a negative strain on the remaining nephrons and the disease progresses.

Causes of (chronic) renal insufficiency in cats

In the case of kidney dysfunction, a distinction must be made between acute kidney disease and chronic kidney failure. Acute kidney disease can be caused by ingestion of toxins such as plants or ethylene glycol (antifreeze that cats find extremely palatable). Infectious diseases, tumors and states of shock, in which there is reduced blood flow to the kidneys, can also be the cause of kidney damage.

Other possible causes for the development of renal insufficiency are, for example, an overactive thyroid gland, in which high blood pressure leads to increased blood flow to the kidney tissue and this is thus damaged. Chronic bladder diseases with pebbles or stones can also "block" the urinary tract and thus cause a backlog in the kidneys. Genetic diseases such as polycystic kidneys represent a slightly lower percentage.

Chronic renal insufficiency mostly affects animals over 10 years of age. What exactly causes it has not yet been finally clarified, but there are genetic causes, infectious diseases and nutrition in the room. The longer lifespan of the animals, due to improved care and prevention, also seems to indicate an increased number of animals with renal insufficiency. The likelihood of developing chronic kidney disease increases with age.

Treatment options for (chronic) renal insufficiency in cats

If you want to prevent the progression of kidney dysfunction, it is important to reduce waste. Unfortunately, this is only possible to a limited extent in cats, since they are pure protein digesters and their metabolic end products are excreted via the kidneys. If the protein in the diet is reduced too much, the cat would continue to break down its own proteins to meet its needs.

If an incipient kidney dysfunction is diagnosed, the first step is to put the animal on an appropriate diet. This means that a reduced amount of high-quality protein is supplied, which produces fewer urinary substances. Thus, the kidney is relieved. In addition, an adjusted phosphate content is an important factor. This has been found to slow the progression of the disease. If the cat does not accept the kidney diet, a phosphate binder can also be used.

If the disease is very advanced, the cat should be taken to a hospital as an inpatient to begin IV fluid therapy. Toxins can thus be excreted more easily and the fluid balance is balanced.