HPM Cat Senior cats’ pathology

Senior cats’ pathology: main clinical conditions

It is generally accepted that a cat can be considered "senior" from the age of 10 years (when it has reached 75-80% of its life expectancy) and that the geriatric stage is reached after 15 years. In practice, one-third of cats over 9 years of age that are considered healthy by their owners actually require medical treatment (95% of which is long-term).

Major clinical entities in the older cat

General studies on senior cats agree that the most common conditions seen in older ones are chronic kidney disease, osteoarthritis, cancers (mammary tumors and digestive cancers are the most common), hyperthyroidism, systemic hypertension, and diabetes mellitus. More than 12% of cats over 9 years of age present two or more concomitant diseases.

Urinary conditions

Glomerular sclerosis and tubulointerstitial fibrosis that develop in the aging kidney result in decreased glomerular filtration rate. The prevalence of CKD is therefore high in older cats: 60% in cats older than 10 years and more than 80% in cats between 15 and 20 years of age. The incidence of CKD is three times higher in cats than in dogs.

The incidence of urinary tract infections also increases with age. Certain conditions in the older cat predispose to the presence of bacteriuria, including diabetes mellitus, CKD, or hyperthyroidism.

Osteoarthritis

Approximately 90% of cats over 10 years of age present radiographic osteoarthritis lesions in at least one joint. Age is a major risk factor: the incidence of feline OA increases by 13.6% per additional year.

Tumors

In intact females, the incidence of mammary tumors increases with age. They occur mostly in cats over 10 years of age. Carcinomas constitute 70-90% of mammary tumors.

Lymphoma is the most common intestinal tumor in cats; in this species, 70% of lymphomas have a digestive location. Low-grade digestive lymphoma accounts for 75% of gastrointestinal lymphomas in cats; it is a small-cell lymphoma, immunophenotype T, and the median age of affected cats is 13 years.

Hyperthyroidism

With a prevalence of 3%, hyperthyroidism is the most common endocrine disorder in the geriatric cat. The average age of affected cats is 13 years. Clinical signs are varied but most often, they include weight loss despite polyphagia. Systolic blood pressure measurement in cats with hyperthyroidism is always advised because hypertension is diagnosed in 15% of cases.

Systemic hypertension

Elevated systemic blood pressure is often present in older cats. In this species, hypertension is defined as a systolic blood pressure greater than or equal to 170 mmHg, or a systolic blood pressure greater than or equal to 160 mmHg with evidence of hypertensive retinopathy or choroidopathy on fundus examination.

The incidence of urinary tract infections also increases with age. Certain conditions in the older cat predispose to the presence of bacteriuria, including diabetes mellitus, CKD, or hyperthyroidism.

Diabetes mellitus

Age is one of the most important risk factors for diabetes mellitus: 75 % of diabetic cats are older than 7 years and almost half of diabetic cats are between 10 and 15 years old.

Hyperaldosteronism

Aldosterone is a steroid hormone synthesized by the adrenal gland. Primary hyperaldosteronism is a rare but underdiagnosed condition because of its frequent association with CKD. The median age of affected cats is 13 years.

Carefully monitor the body condition score

Body condition score (BCS) tends to decrease in geriatric cats due to decreased appetite (oral pain, less acute olfactory sense) and digestive abilities. After 14 years of age, cats are also more prone to sarcopenia.

The causes of a severe weight loss should be investigated as it is often an indicative sign of a significant disease. In cats with cancer, CKD, or hyperthyroidism, weight loss starts approximately 2.25 years before death. In geriatric cats, a weight loss of 100 g increases the risk of mortality by 6.4%.

The health check-up of a senior cat

In an aging cat, regular clinical examinations provide biological references and make it easier to detect the onset of a problem. A basic check-up should be done once a year for cats between 7 and 10 years old, with the frequency increasing with age. During the physical examination, it is important not to forget to examine the oral cavity.

Routine complementary examinations will usually include: a complete blood count, a basic biochemical check-up (total proteins, glycaemia, blood urea, creatinine, PAL, ALT...) and a urinalysis (dipstick, specific urine gravity, protein/creatinine ratio to evaluate the renal function). The urine sediment will be analyzed in case of abnormalities.

The owner will also be proposed the blood pressure measurement and a thyroid hormone dosage for his cat.


The American Association of Veterinary Hospitals (AAHA) has just released its recommendations for the care of senior cats. According to the AAHA, practitioners should assign special status to these older animals because their owners usually have a strong bond with them. More time should be set aside for consultations dedicated to senior cats. A clinic can also promote itself as "senior friendly" by ensuring that senior animals are well represented in the visuals displayed in the clinic and on the clinic's website. Learn more about senior friendly clinics: DHALIWAL R., et al., “2023 AAHA Senior care guidelines for dogs and cats”, J Am Anim. Hosp. Assoc., 2023, 59, 1–21.

Sources

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Feline chronic kidney disease

Feline chronic kidney disease (CKD) is a condition with a late clinical expression. It results from the progressive reduction in the number of functional nephrons due to irreversible nephropathy, usually bilateral. It is important to detect it as early as possible and to evaluate its stage of evolution according to the classification proposed by the International Renal Interest Society (IRIS).