Geriatrics by Margot Schwag, VMD
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The geriatric dog, like his human counterparts, has special needs. It is the veterinarian's job to educate pet owners, to identify these inevitable changes and, when able, to slow or deter these changes through proper veterinary and home care. Life expectancy for a Doberman averages from ten to twelve years. They enter the geriatric stage around seven to eight years of age. Health care management components include: nutrition, proper vaccinations, parasite treatment and control, avoidance of excessive stress, early disease diagnosis, and specific therapeutic regimens.
Geriatric patients differ from their younger counterparts in that they are more likely to have multiple health problems. The metabolic rate slows, the ability to withstand stress, the capacity to metabolize drugs, the capacity for thermoregulation and sensitivity to thirst are decreased, as well as the ability to fight off infection.
Nutritional changes can be dramatic. Overall caloric requirements drop 2040%. Accordingly, these pets must be fed a high quality food that is reduced in calories (decreased protein, increased carbohydrates). Exercise can lessen hunger pangs, burn calories, and add muscle tone. Typically, the percentage of body weight represented by fat increases with age.
Oral hygiene is very important. It is estimated that proper dental care can extend an animal's like span by at least 20% by controlling toxins produced by resident oral bacteria. Bacteria and toxins shed from the oral cavity can be absorbed from the intestines, then enter the blood stream and be distributed throughout the body. Increased fiber, exercise, prevention of constipation, and dietary additives (antioxidants) can help decrease absorption. Dietary copper and salt should be kept to a minimum.
Daily function of the kidneys can result in compromised ability to filter and excrete waste products of metabolism. As a result waste products can accumulate in the blood, which causes additional secondary effects to the body (please refer to 1993 Vol. 3, Issue 2, Page 3 for article titled Chronic Renal Failure).
Urinary incontinence is a common problem in the aged. Incontinence may be due to nerve damage, vascular (blood supply) changes, or hormone deficiecies. Chronic cystitis may be secondary to the bladder not being able to empty completely. Dogs should be offered fresh water since their sense of thirst can decline with age. Dietary changes in the event of compromised renal function include decreased phosphorus and sodium. Early signs of renal insufficiency include increased thirst (polydipsia) and increased urination (polyuria). Additional signs include dehydration, constipation, weight loss, lethargy, vomiting, appetite suppression, hypertension (elevated blood pressure) and anemia.
The liver can also deteriorate with daily use. Clinical signs can be very mild, including weight loss, lethargy, and decreased appetite. Additional signs include fever, vomiting, diarrhea, ascites (fluid buildup in the abdomen), edema (fluid buildup in body tissues), jaundice, polydipsia, and polyuria.
The liver has multiple functions. These include drug metabolism, coagulation (blood clotting), bile production and excretion, storage and activation of vitamins, food metabolism, etc.
The heart can undergo many changes including arrhythmias (rhythm disturbances), poor cardiac muscle contractility and abnormal blood flow, and valvular insufficiency. Decreased cardiac output and poor blood circulation may result in fluid buildup in the chest (pleural effusion) or abdomen (ascites). Fluid in the chest cavity can limit the lungs' ability to fill with oxygen. The animal may present with labored breathing and/or cyanosis (bluish tinged gums due to low oxygen delivery). Poor oxygen delivery to the brain and muscle may cause abnormal mentation and exercise intolerance.
Fluid can build up in the body cavity due to poor blood circulation. This fluid will put pressure on the gastrointestinal tract causing vomiting, diarrhea, and loss of appetite. Weight control is very important since the excess weight may put excess stress on an already nominally functioning heart. Mild exercise will be helpful; however, it is important not to stress the animal.
Normal lung tissue is very thin and elastic allowing for ease of oxygen transfer from the airways into the bloodstream. As the pet ages, the lung tissue loses elasticity and becomes more fibrous (thicker), normal mucous thickens and ciliary movement decreases. When this happens, the lungs can't clear debris and mucous from the passageways as easily. Due to these changes, it becomes more difficult for the animal to breathe. The dog may also have problems with a chronic cough in an attempt to clear their passageways. This cough can be exacerbated by exercise and/or excitement. Common respiratory problems of aging dogs include:
chronic obstructive pulmonary disease
Cough may also be due to an enlarged heart pushing on the main stem bronchi of the lungs.
Early recognition and treatment of respiratory infection, allergies, and reduction of airborne pollutants will decrease lung pathology.
With age, dogs can suffer from senility and dementia just like humans. Causes include decreased levels of neurotransmitters, receptors and poor blood circulation. Cerebrovascular accidents and perivascular hemorrhage may also occur and cause profound brain damage.
Exercise promotes good blood supply to the brain, helping to avoid hypoxia (low oxygen levels) and cell death. Like humans, failing eyesight, difficulty in hearing, decreased taste differentiation, and lenticular sclerosis (clouding of the lens) are common senile changes. Cataracts, retinal degeneration, and glaucoma occur in pets as well.
A decrease in tear production can lead to increased mucous formation in the eyes which will lead to dry corneas. Increased irritation and corneal pigmentation may result in decreased vision.
The musculoskeletal system is very susceptible to age changes. Muscle mass and tone typically decrease, while the percentage of body fat to muscle ratio increases. The abdominal muscles may become flaccid, therefore the potbellied appearance. Joints become arthritic due to years of use and abuse. These dogs are slow to get up after a nap; they are initially lame but warm out of the stiffness within minutes of movement.
Muscle tremors occur more commonly in the aged. The muscles of the hind legs commonly atrophy due to decreased muscle innervation and exercise. It is very important that these arthritic, weak animals are not overweight. Owners should be able to feel rib directly under the skin over the rib cage. The animal should have a narrowed waist when viewed from above and the side. Exercise is very important to retain muscle tone and joint range of motion.
Nutrition and Endocrine
Nutritionally and hormonal changes can cause a poorly conditioned hair coat. The pet may lose hair and the hair becomes dull, dry and brittle. The skin can lose its elasticity, become thin and appear like tissue paper. As a result, it is more prone to being damaged. Hair follicles can become plugged with keratin (a protein produced by the skin). The sebaceous glands (oil producing glands) may proliferate abnormally to form raised irregular wartlike lesions in the skin.
Proper nutrition, vitamins and fatty acids will help to maintain the health of the hair and skin. Hormonal changes, metabolic disease and environmental factors (low humidity) need to be identified and treated as applicable.
In general, most hormones decrease in activity with age as a result of decreased hormone production, receptor binding, and increased resistance of tissue to the action of hormones. Thyroid hormone levels typically lower, leading to possible hair loss, weight gain, lethargy, etc., (see 4th Quarter 1991 Issue, page 3 on Hypothyroidism). Cortisol, a hormone produced by the adrenal gland, typically elevates, which results in weight gain, hair loss, increased appetite, increased thirst and urination, etc. Sexually intact animals are at greater risk for breast cancer or testicular cancer.
Every day, cancer cells are liberated from tissue and circulate throughout the body. While the immune system is healthy and functioning well, it identifies these abnormal cells and destroys them. With age, the immune
system is not as competent as it once was. As a result nepotistic (cancer) cells evade the immune system and establish themselves in the body. Unfortunately, dogs are capable of contracting approximately 350 different types of cancer.
Diagnosis and Prevention
Preventative geriatric care should begin when a dog enters middle age. The veterinary clinician's responsibility to the dog is to delay unavoidable progressive deterioration of the body systems and provide an improved quality of life for the animal's remaining years. Veterinary visits should increase to twice yearly. Baseline complete blood counts and serum multiple assays should be performed as well as an urinalysis and a weight control program (when indicated). Owners can watch for changes in appetite, thirst, bowel movements, weight and activity. Additional tests available include electrocardiograph, thoracic (chest) and abdominal radiographs (xrays), and possibly echocardiography (ultrasound), thyroid gland and adrenal gland tests, and blood pressure evaluation.
Preventative health care should also include dentistry’s when required, annual vaccinations (since older dogs may have compromised immune systems, they are more susceptible to parvo virus, distemper virus, etc.), heartworm checks and fecal exams. Early cancer detection via palpation, radiographs, biopsies, etc. are also very important.
Owner commitment is the single most important factor in determining the success of a geriatric health care program. A proper diet and moderate regular exercise are key to good old age health. The clinician can provide the information regarding the animal's needs, but the owner must see that they are met. Every animal responds to the aging process differently; each animal must be evaluated independently.
The most important issue is quality of life. I feel strongly that quantity of life is no life, if there is no quality. If the dog no longer enjoys a walk, eating its food, interacting with its owners, is the dog happy? It's paramount to keep our "kids" healthy and happy and to ensure a graceful and dignified old age, and to be compassionate and unselfish when it is time to say goodbye.
For permission to reprint contact Margot Schwag, VMD, Landisville Animal Hospital, 3035 Harrisburg Pike, Landisville, PA 17538.