Geriatrics – don’t ever forget me.

Geriatric medicine (= medicine for the elderly) has become an indispensable speciality in human medicine. Specialisation because this field of medicine deals with age-related and age-typical diseases, but also with complex disease conditions (= multimorbidity). Similarly, geriatrics is becoming increasingly important in veterinary medicine, as our dogs and cats are aging too. Therefore, preventive health care makes perfect sense for seniors (cats aged 9-14 years) as well as geriatric cats (15 years and older).

Enhance quality of life

Age-related conditions in cats are often difficult to differentiate from disease-related problems. This applies, for example, to impaired hearing and vision. Accordingly geriatric health care aims to detect age-related diseases such as CKD, but also neoplasms, at an early stage before the first symptoms appear, in order to improve lifespan and quality of life.

The older the oftener

Preventive examinations for cats start at the age of 7 years and include annual check-ups with laboratory tests (e.g. blood and urine) and general examination of the cat. Furthermore, it is recommended that the cat’s blood pressure is measured. Since elevated blood pressure and CKD are directly related.

A high score is a bad sign

Geriatric cats without any symptoms should still have a health check twice a year (every 6 months) including blood pressure measurement. In addition to the above-mentioned examinations, it is important to check and control the weight. A weight loss of 5-10% is already considered abnormal. Weight loss is considered a risk factor for CKD and is associated with a poorer outcome.
To assess weight, the Body Condition Score (BCS) is determined both visually and by palpationUsing touch to check sites and organs of an animal’s body to diagnose disease. Palpation is part on a clinical examination.... of the cat’s body, in addition to weighing. The BCS is divided into 9 scale levels and assessed according to the cat’s muscularity and fat mass. With this score model cats are divided into different levels of underweight (score 1-4), normal or ideal weight (score 5) and different levels of overweight (score 6-9).

A cat’s muscular condition is examined with the Muscle Condition Score (MCS). The four-level classification differentiates between normal muscular condition and three levels (mild, moderate, severe) of muscle atrophyWasting away of tissue, a reduction in the volume and/or size of tissues or organs..... The classification into one level is based on the palpation of the back muscles along the spine, the muscles at the shoulder and the back of the head as well as the muscles of the pelvic bone. Muscle atrophy may be associated with a condition such as CKD and/or hyperthyroidism (overactive thyroid). However, a decrease in musculature is to be expected in older cats in general.

A glance into the muzzle

During general examinations, the inspection of the oral cavity is considered to play an important role. This may reveal the presence of FORL= Feline Odontoclastic Resorptive Lesion = degradation of the tooth by the body's own cells which destroy the tooth...., which can then be followed up with a dental radiograph. Dental lesions and weight loss are typical risk factors for the development of chronic kidney disease in the cat.

Creatinine illusion

During blood testing, the kidney parameters are determined. In particular, the blood levels of creatinineCreatinine is a breakdown product of muscle metabolism. Its blood level is dependent, among many factors, on age, weight, nutritional status and muscle mass. Hence, creatinine levels in the blood vary from individual to individual. Creatinine is continuously excreted in the urine. Increased blood creatinine..., ureaUrea is the nitrogen-containing breakdown product of protein metabolism. The nitrogen from the proteins is converted to ammonia in the liver, which is combined with carbon dioxide to form urea. This is continuously excreted via the kidneys but also via sweat. Urea is one of..., calcium and phosphorus are examined more closely. Since changes in creatinine blood level can be a first important indication of the presence of CKD, a change in the muscle metabolism must be ruled out beforehand. Creatinine is involved in muscle metabolism and is correspondingly elevated when muscle degradation is taking place. This can be age-related, but can also be associated with hyperthyroidism. In this case, more creatinine is released from the muscle breakdown, so that blood levels increase.

The situation is different in the case of CKD. Here, the creatinine cannot be excreted sufficiently via the kidneys. This results in higher blood levels, since more creatinine remains in the blood. Unfortunately, creatinine levels are dependent on many factors, so the normal range of creatinine blood levels is very wide. This makes it difficult to get clear indications of the presence of CKD. With regular blood checks, an increase in the creatinine blood level even within the normal range is already a first indication of a CKD. An additional SDMASDMA = Symmetrical Dimethylarginine, which is a degradation product of the amino acid arginine and is excreted solely through the kidneys. SDMA is a highly specific biomarker for kidney function in cats. Read more: SDMA test (blood test)... test can be helpful at this point. The SDMA rises in a specific way to indicate the impaired kidney function.

When specific gravity of urine decreases, “water level” in the cat’s body drops

A laboratory examination of urine includes the determination of its specific gravity, which decreases in the presence of CKD. The urine becomes less concentrated in chronic kidney disease because it contains more water which the damaged kidneys can no longer retain. The CKD cat thus loses important fluid through the urine, which can lead to dehydrationA deficit of total body water. Dehydration can be caused by excessive fluid loss, for instance via the kidneys in CKD, or by insufficient fluid intake..... This is a risk factor for the development of CKD. Therefore, the specific gravity of the urine declines.

The so-called urine creatinine quotient (UPC) is used to determine the presence of protein loss through the urine. If it is elevated, it indicates the presence of proteinuriaIncreased protein in urine, leading to loss of protein. Normally, only a very small amount of protein is excreted in the urine. In chronic kidney disease, the amount lost may increase. High blood pressure damages blood vessels in the nephrons making them more permeable and..., which occurs in connection with CKD.

Dementia – an issue in geriatric cats

In older cats, behavioural changes can be observed that are associated with cognitive dysfunction. Moreover, these behavioural changes can also be associated with high blood pressure (hypertensionHigh blood pressure.) or hyperthyroidism. Both of the latter diseases are in turn closely related to CKD.

Bibliography:

• Greene, J. P. / Lefebvre, S.L. / Wang, M. / Yang, M. / Lund, E. M. / Polzin, D. J. (2014): Risk factors associated with the development of chronic kidney disease in cats evaluated at primary care veterinary hospitals. In: Journal of the American Veterinary Medical Association 244(3), S. 320–327.
• Weingart, C. / Kohn, B. (2020): Gesundheitsvorsorge bei der geriatrischen Katze. Tagungsunterlagen DVG-Vet Congress 2020, Berlin, S. 53–56.

Good illustrations of the scores can be found at: https://vet.osu.edu/vmc/companion/our-services/nutrition-support-service/body-condition-muscle-condition-score-charts