Diagnosing and managing common age-related problems in older pets (Proceedings)
"Old age" in not a disease but is the sum of the deleterious effects of time upon the cellular function, microanatomy and physiology of each body system. These biological aging changes manifest in progressive deteriorations in physical condition, organ function, mental function, and immune response, but not necessarily correlating with the patient's actual chronological age. Consequently, each internal organ system will age at a different rate; biological aging. Using the patient's age as a benchmark of his collective decline is appropriate. However, because each organ has a different rate of biological aging, any critical assessment of a patient's overall health status should be based on a comprehensive health screening of both mental and organ functions, when possible.
Aging in dogs and cats is associated with gradual and progressive deterioration in the delicate body systems that eventually results in anatomical changes and decreased physiological functions. As the functional organ reserves are gradually lost, the long-term result is a physiological decline of the major organ systems leading to an altered response to stressors, infections and various drugs. At some stage in the progressive decline the "tipping point" is reached, all physiological reserves are exhausted resulting in overt changes in diagnostic screening tests, biochemical parameters, and/or the onset of clinical symptoms of age-related disease referred to as "benchmarks". Usually these slowly progressive organ system changes are subtle; undetected by the owner or miss-interpreted by the owner, until the patient is stressed by an unrelated illness, boarding, medications or general anesthesia. Increasingly, those benchmark changes are being routinely identified on senior wellness screening tests, further validating the value of such standardized testing protocols.
Decisions regarding specific drug therapies, anesthetic protocols, pain management strategies, and quality of life issues hinge on the variety of declining physiological "benchmarks." A knowledge and clear understanding of the level of physiological decline of each organ system dictates how a specific patient is best managed. Assessment of the level of physiological decline in each organ system requires diagnostic evaluations. The interpretation of a patient's urinalysis, hematology and biochemistry panels results in data used to aid in the diagnosis, prognosis and treatment of various conditions. Combined with appropriate imaging techniques and other advanced diagnostics presumably will facilitate early identification of both physiological decline and various pathological states. Three gerontology reference books one should consider for their library include J. Hoskins, Geriatrics and Gerontology of the Dog and Cat, 2nd ed.; the Veterinary Clinics of North America, 2005 Geriatrics Ed; and U. Mohr; W.W. Carlton; D. L. Dungworth, Pathobiology of the Aging Dog (vol. 1 & 2).The generalized changes associated with aging include dryness of all tissues, progressive degeneration of organ function, tissue hypoxia, cellular membrane alterations, decreased enzyme systems, decreased immune competence, and definite personality alterations.
The ten most common causes of death in older dogs, based on a study funded by the Morris Animal Foundation for Animals, are cancer, cardiovascular disease, renal failure, epilepsy, hepatic diseases, bloat, diabetes, stroke, Cushing's disease, and immune mediated disease. The ten most common causes of death in older cats are cancer, cardiovascular disease, renal failure, diabetes mellitus, FIP, FIV, FeLV, hyperthyroidism, liver and infections. It is important to convey this pertinent information to owners and staff. Intimate knowledge of the early warning signs of the 10 most common life threatening diseases in the elderly pets, alerts the health care team of impending health threats in a timely manner. In addition the list is helpful in determining what specific tests should be included in your "Senior Care" health screening program.