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Managing common behavioral changes in older pets (Proceedings)

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Apr 01, 2008

Definite personality changes and behavioral problems can be extremely challenging to the practitioner and extremely frustrating to the client. Some problems are mild and acceptable, while others are major concerns initiating euthanasia discussions. Referral resources for complex behavioral problems include American College of Veterinary Behaviorist 409/845-3195; Animal Behavior Society 781/891-4200; and American Society of Animal Behavior 630/983-7749.

General behavioral changes are elderly patient's desire more attention, are more jealous, are more irritable, are less mentally alert, and have altered sleep cycles. 60% of pets sleep in the owner's bed or in the bedroom according to a AAHA sponsored study. Altered sleep patterns are common geriatric "behavioral" dilemmas especially in those situations where both the patient and owner are affected. The owners report one or more of the following complaints; pacing at night, periods of panting, awaking the owners to go outside for no obvious reason, inability to get comfortable or constantly "fluffing" their bed. Various causes include an underling painful condition such as osteoarthritis, spondylosis or a chronic IVD; sleeping on a hard surface; an altered biological clock where they sleep all day then can't get to sleep at night; cold from poor circulation or a basal metabolic rate or a poor thermoregulation; or a phobia of the dark. This complaint can also be linked with Canine Cognitive Disorder. The author would advocate the following options; a warm soft bed, a night light, a radio playing softly, a brief walk before bedtime, hydroxyzine 1-3 mg/kg prior to bedtime, melatonin 1-3 mg, and/or a 2 week trial of a short term pain management program.

Cognitive Dysfunction Syndrome

Many of these common "old dog or old cat" behaviors are often grouped into a syndrome called Cognitive Dysfunction Syndrome (CDS). CDS is a progressive disease syndrome of older dogs and cats associated with some brain pathology that results in commonly recognized group of behavioral changes. The clinical signs in older patients are related to impaired mental function commonly referred to as "senility, dementia, or doggy Alzheimer's disease". Impairments in memory, learning, perception and/or awareness are common. CDS is a progressive disease of the brain in older dogs and cats associated with changes in behavior.

The pathogenesis of CDS is complex and is associated with four categories of pathology each resulting in altered behavior. Initially any one of the following agents will initiate varying degrees of neuronal dysfunction that can be reversible if treated early. Except with alterations in neurotransmitters levels, with time the damaged neurons will eventually die leading to permanent abnormal behavior. This explains why some treatments may be not be beneficial at all or become less effective with time.

One cause of CDS is the accumulation of metabolic waste products in the neurons. The primary offender in humans, dogs and cats is Beta amyloid that exhibits characteristic plaques when viewed on histopathology sections. Initially any behavioral changes associated with Beta amyloid can be attributed to neuronal dysfunction but eventually the affected cells will die. Another category of causative agent is hypoxia. Decreased oxygen to neurons will result in neuronal dysfunction and eventually neuron death. The hypoxia can result from decreased cardiac output, chronic pulmonary disease or vascular compromise from arterial constriction or sclerosis. Another area of current CDS research focuses on the age-related decreases in various CNS neuro-transmitter levels i.e. ACH, GABA, dopamine, nor-epinephrine, or serotonin. The confirmatory diagnosis of a specific neurotransmitter deficiency is based on the patient's behavioral response to any replacement therapy. The last category of a cause for CDS involves the deleterious affect of oxygen derived free radical on brain neuronal function. There has been considerable research into the effects of positive effects of anti-oxidants on brain function in patients with CDS. Antioxidant packages are becoming common place in most quality senior diets and are currently being investigated as possible preventatives for many age-related diseases.

The common clinical signs of Canine Cognitive Dysfunction fall into four distinct categories found in the acronym DISH. The D= disorientation / confusion: the I = decreased interactions with family or housemates; the S= Sleep cycle disturbances; and the H= house soiling. It is important to note that most cases of CDS have symptoms in only one or two of the four categories. In the feline, the common clinical signs of CDS include one or more of the following; aggression, inappropriate elimination, increased vocalization, sleep cycle disturbances, excessive grooming, and/or disorientation/ confusion.