Diseases of Older Cats

However observant you are, cats are good at hiding symptoms and may be very sick by the time you notice anything and see the vet. You might wonder why this is. It is an evolutionary survival trait - a sick cat attracts the attention of a larger predator; hiding symptoms may be great in the wild, but presents a problem in the home where early detection means treatment is more likely to be successful. There are many excellent cat care books (many are well illustrated) detailing feline ailments. You can also do a web search, email an on-line vet or phone your regular vet. This section concentrates on conditions more common in older cats.

Kidney Failure

The kidneys filter the blood and remove metabolic waste products which are excreted in the urine. If these waste products (e.g. urea) are not removed, blood toxin levels rise making your cat ill. The kidneys are usually the first organs to wear out. Kidney disease is ultimately fatal; early diagnosis can slow its progress. Some breeds are susceptible to kidney problems e.g. hereditary polycystic kidney disease (PKD). Due to the wear and tear of a lifetime of service, the kidneys wear out. Chronic nephritis (inflamed kidneys) resulting in scarred and shrunken kidneys, is the most common cause of chronic kidney failure in older cats.

Chronic kidney disease (Chronic Renal Failure, CRF) is a progressive, fatal condition as kidney function progressively decreases and don't filter the blood properly. At the same time, protein is lost through the kidneys and can be detected in the urine. Supportive treatment (special diet, dialysis, drug treatment) can extend your cat's life and give good quality of life for several months but he will lose too much kidney function to survive. He may show no symptoms until only 30% kidney function is left and his blood urea levels are extremely high.

Symptoms of kidney failure include poor appetite, weight loss, increased or excessive thirst, increased urination, bad breath, mouth ulcers and vomiting. If he goes outdoors he may show an unusual preference for drinking greenish standing water or pond water. In the later stages he may suffer seizures or coma as toxins accumulate and circulate in the blood and affect his brain. Death due to blood toxicity is slow and usually unpleasant as other organs are being poisoned.

As kidney function reduces, they produce more urine to flush out the metabolic wastes and your cat drinks more water. This is the body's version of dialysis. The kidneys can only process a limited amount of fluid per day. Potassium, an essential mineral, is lost in the urine and low potassium levels in the blood (hypokalaemia) further damages the kidneys, causing a vicious cycle. Your vet may prescribe potassium supplements to counteract this. The effects of kidney failure can be reduced, but not cured, by medication and a low-protein, low-sodium, low phosphorus diet, which produces fewer waste products. These foods are commercially available in the US. In the UK they are available on a vet prescription. Plenty of fresh water is crucial.

Due to the cat's low blood volume, human-style dialysis (fluid therapy) on a kidney machine is not possible. Your vet may inject extra fluid into a vein, under the skin or into the abdomen. This increases the blood volume, blood pressure in the kidneys is increased and they filter better. The effect is temporary and frequent dialysis is distressing to most cats and may require regular anesthesia which is riskier for older cats.