SENIOR PET MEDICAL CONDITIONS
As any individual ages, the organs in the body have to function longer and longer to keep the body performing at peak function. No one can blame anyone for getting ill but a lot of a pets longevity and health in its senior years depends upon the owner. There are breed predilections for certain diseases such as Canine Hip Dysplasia in German Shepherds but to a greater extent, factors such as frequency of veterinary care, diet, reproductive status, using leashes, amongst others tend to dictate how long an animal stays healthy. Senior pet medical conditions are those most commonly seen due to failure of certain organs or body parts.
This is not supposed to be an exhaustive list of everything that goes wrong with senior pet medical conditions but it describes some of the more common conditions seen in older dogs and cats. A general discussion of each disease is presented with the goal of having the reader gain a greater understanding of these diseases so that veterinary care may be sought sooner rather than later.
This is one of the most common diseases seen in the older dog or cat. Cancer is a general term that can effect any organ in the body. Any cell can have genetic DNA mutations that can cause a cancer to develop. One of the most visibly detected cancers originate in the skin. Malignant melanomas are common in darker, grey coated or skin colored dogs or cats. Melanomas are usually small, cauliflower lobed, dark growths that can be found all over the skin surface. There are even melanomas (amelanotic) that look like warts but are melanomas but lack the black pigmentation. All melanomas should be surgically excised. ANY mass on the skin should be investigated by a veterinarian. One of the deadliest forms of melanomas is the oral melanoma. Veterinary oncologists have at their disposal a relatively new vaccine for oral melanoma named Oncept®.
Breast cancer in the non-spayed female dog and cat is common in senior pets. Each heat cycle that a cat or dog goes through increases the risk of breast cancer. This is why there is a zero chance of getting this if the animal is spayed at 6 months of age before her first estrous cycle. Most tumors are seen in the 4th or 5th mammary gland pair. In the dog, mammary tumors can be mixed, that is to say benign or malignant. In the cat they are always malignant. All pets have a chest film performed to make sure there are no visible cancer lesions in the lungs. The mammary masses are surgically removed and the female is spayed at the same time.
Bone cancers are relatively common in older dogs. Osteosarcomas are some of the most common. Most commonly they present with a hot to touch swelling of the stifle (knee) joint. This cancer often causes bone lesions at the lower end of the femur; which is the long bone of the leg. Even with chemotherapy, the life expectancy is relatively low, often less than a year.
Tumors of the spleen are very common in large dogs but I have even seen them in small dogs. These are usually hemangiosarcomas that cause the spleen to enlarge and fragment causing a tremendous accumulation of blood in the abdomen. Emergency surgery and a splenectomy are performed. This is a life threatening event. There are complications but most dogs do well. Hemangiosarcomas are also seen on the skin and the right auricle of the heart.
There is one cancer that is rarely seen in the dog and that is bladder cancer. It is common in humans that smoke but in my career I have had only one case that was in an Norwegian Elkhound. Other cancers or neoplasms seen in the dog are those of the lymphatic system such as lymphoma or lymphosarcoma; both of which involve enlargement of the regional peripheral lymph nodes as well as internal lymph nodes. Diagnosis is via biopsy of the effect lymph node and treatment is with corticosteroids and other chemotherapeutic drugs known as the COP Protocol.
Senior pet medical conditions associated with the reproductive tract are common. The most frequently seen in the non altered female dog or cat is pyometra. Outside of breast cancer this is seen just about as frequently in most veterinary practices. It is caused by an excess of progesterone, a female hormone, that causes endometriosis and a severe secondary infection of the entire uterus. The uterus fills up with pus and the animal will not survive if an emergency ovariohysterectomy is not performed. Classical signs of lethargic, fever, excess drinking of water and a pussy vaginal discharge are classical. Imaging and a Complete Bloodcell Count (CBC) also can help in the diagnosis.
Urinary Incontinence is also a problem in the older spayed female. It is usually caused by a decrease in estrogen production. Although some estrogen is produced in the adrenal cortex, most of it is produced in the ovaries which are removed when the dog is spayed. She will often urinate while she sleeps or rests and usually is not aware of it happening. Urinary bladder infections have to be differentiated from incontinence. When diagnosed, most dogs are put on twice a day dosing of phenylpropanolamine which usually does the trick. Way back (and it still can be compounded) I used DES (Diethylstilbestrol). Once or twice a week and it was great. Cats rarely have these issues.
False pregnancy is also seen in the older female. This is usually seen about 1 or 2 months after the female is in estrous. The animal has a history of irregular estrous cycles plus shows signs of nesting behavior and some even go into a false labor. These senior pet medical conditions predispose the dog to a higher risk of breast cancer so it behooves the owner to have the animal spayed.
The most common male reproductive disorders are prostate enlargement and testicular cancer. Most dogs 5 years of age and up have some degree of prostate enlargement. The prostate gland is under hormonal control and testosterone, which is produced in the testes, causes the gland to enlarge. This crimps or narrows the diameter of the urethra (the outflow tract of urine from the bladder to the outside). This can cause straining, urinary tract infections and urinary tract obstructions in severe cases. Treatment of basic cases involves neutering. This reduces the enlarged prostate gland in about 2 weeks. Obstruction cases require medical and or surgical intervention.
The most common testicular cancer is the Sertoli Cell Tumor. They are most commonly seen in dogs that have retained testicles (cryptorchidism). Feminization of the male is hallmark with breast enlargement being the classical finding. Neutering the male is effective and this includes removing the retained testicle which usually is in the inguinal canal or abdominal cavity. Sending the testicle for a histopathological diagnosis is recommended.
Heart disease is seen daily in most practices. It is lumped into 2 groups of animal sizes. Small and medium size dogs usually develop mitral disease or left sided heart failure while large breeds of dogs develop cardiomyopathy which is a thickening of the myocardium that effects the volume of blood pumped to the rest of the body. From being overworked, the myocardium dilates and heart failure worsens. Cats also develop hypertrophic cardiomyopathy and the majority of them are asymptomatic. As I have mentioned many times, cats are like Houdini when it comes to disease; they act like nothing is bothering them! In cats this is often diagnosed at autopsy. In all species, clinical signs such as: pulmonary edema (fluid in the lungs), trouble breathing, coughing, lethargy and inability to exercise are hallmarks of heart disease. Fortunately over the last few years they have developed heart markers such as Idexx Labs® Pro BNP, a fabulous test that gives the doctor an actual number to differentiate if the animal has actual heart disease or pulmonary disease. Treatment is geared to assisting the contractile force of the heart muscle and eliminating the pulmonary edema with diuretics. Other medications used are: theophylline, benazepril, pimobenden plus diets low in sodium.
One of the most common senior pet medical conditions seen in older dogs is hypothyroidism. This is a disease that is characterized by a decrease in thyroid hormone. It can present itself in a myriad of ways but most commonly I see weight gain, lethargic, poor skin condition and once in a while a slower heart rate. It is easily diagnosed looking at T4 and FT4 levels and or a TSH test. Affected dogs are put on T4 (levothyroxine) supplements twice daily and checked regularly to make sure the prescribed dose is keeping the levels at normal levels. Dogs feel and act much better.
Hyperthyroidism is just the reverse of hypothyroidism and is seen exclusively in the senior cat. In all cats ten years of age and older I incorporate thyroid testing. Most cases are seen in this age group and are common cases in all medical practices. For some reason, the majority of cats I have diagnosed were black cats! The typical history is a cat that is drinking lots of water, panting a lot, flooding the litter box and eating a lot of food but it is losing weight!! This has to be differentiated from diabetes mellitus, as both diseases have very similar signs except in the former, thyroid hormone levels are usually off the chart. These are very satisfying to treat. Treatment is with Tapazole® (methimazole) or with radioactive iodine. The latter is becoming more popular and a bit cheaper over time. It is a one time treatment with about 14 days of hospitalization until the radiation subsides but successfully destroys the thyroid tissue. Cost now is about $800-$1000 per cat. It does not require surgery or anesthetics; which are risky with cats with hyperthyroidism. The oral route is a life long endeavor. The drug takes 3-4 weeks to work but if you miss doses the thyroid levels start creeping up fast. Even though most cases are caused by a thyroid adenoma almost all cats do well on either regimen.
Hyperadrenocorticism (Cushing’s Disease) is commonly seen in older dogs particularly: Miniature Schnauzers, Boston Terriers, Poodles, Maltese and other small breeds; even though it is sometimes seen in larger dogs. Signs of excess drinking and urinating, development of a pot belly and others are often seen. Most of the time it is pretty easily diagnosed via the ACTH Stimulation Test. 90% of all cases are caused by a pituitary tumor and the rest by adrenal gland tumors and by excess oral glucocorticoid (prednisone) administration. Treatment used to be with mitotane but now a days most practitioners use Vetoryl® (trilostane).
Diabetes mellitus is the most common version of diabetes. It is commonly seen in obese animals and dogs suffering from acute pancreatitis; particularly in Miniature Schnauzers. The bottom line cause is insufficient insulin production (or insulin resistance) in the beta cells of the islets of langerhans. There also exists the lesser seen Diabetes insipidus which is caused by the lack of ADH (Anti-Diuretic Hormone) produced in the posterior pituitary gland. Most dogs and cats drink excessive amounts of water, urinate excessively and eat a lot. They also are weaker than normal. Often picked up by owners where the urine on the floor has dried, is that it is “sticky”. That is because of the sugar in the urine. To diagnose diabetes mellitus you must have 2 factors: hyperglycemia (elevated blood sugar) and glucosuria (positive urine sugar). Many diabetics (about 15-20%) are not only diabetic but Cushingoid. In this case, treatment for Cushings is added and the dose of insulin is cut in half and adjusted as needed. Uncomplicated diabetics are put on once or twice a day insulin plus low fat and carbohydrate diets such as Hills® W/D canine or feline. Blood glucose levels should be checked regularly.
LIVER AND KIDNEY DISEASE
Most senior pet medical conditions originate from faulty organ function. As organs fail, they can not keep up with the demands of the rest of the body. Their workload backs up and because of that their waste products enter the circulatory system and cause havoc on the body. By the time blood work shows an elevation in the organ functions of these two organs, about 75% of the function of these organs have been altered for the worse. That means that there is about 25% of the organ that is trying to carry the load for the total 100%. That is difficult to do.
Liver disease is crucial as the liver is just as busy as downtown Manhattan is! All the nutrients are brought into the liver where they are broken down, built up again into needed components (like proteins) and distributed to the rest of the body. The liver breaks down toxic components into stable components such as secreting waste products from taking regular prescription medications. The liver, in essence, is a huge factory! This is in part due to the presence of a liver enzyme known as glucuronyl transferase. Cats do not produce this which causes havoc if you try giving certain human/dog medications to cats!
When an animal is obese, it often has a fatty liver. Fat cells clog the normal pathways of fluids within the liver. Sort of like traffic in midtown Manhattan, that fluid becomes sluggish. Waste products are absorbed such as bilirubin (a bile pigment) and the animals skin and other parts of the body turn yellow. This is called jaundice. It is not itself a disease but a symptom of liver disease. In pets, jaundice is noticed earliest in the soft palate of the mouth, conjunctiva of the eyes and the ears.
Liver disease can be primary in origin such as specific tumors known as hepatomas or most commonly secondary to another condition such as Cushing’s Syndrome. In either case, dogs often are tired, may have fluid in their abdomens (ascites), enlarged livers plus an increase in thirst and urination. Treatment is geared towards the primary cause but many times treatment is supportive since it may be difficult to find an exact cause.
Kidney disease is one of the most common senior pet medical conditions seen in the senior dog or cat. The job of the kidney is to transport soluble wastes, via mixing with water, and passed to the exterior in the form of urine. If an animal is in acute renal failure there often is not enough water that reaches the kidney so that wastes can be eliminated. Sometimes the organ itself is damaged by tumors (nephromas), infections (pyelonephritis) or amyloid; a foreign protein that disfigures the kidneys anatomy. Renal disease is diagnosed by physical exam and appropriate blood work. Specific renal tests are: BUN, creatinine and UPR (Urine Protein Ratio). Treatment is geared at the primary cause but usually includes intravenous fluids and other supportive care and diet changes.
Glaucoma and Keratoconjunctivitis sicca (KCS) are the two most common diseases of the senior dog and cat. Glaucoma is defined as an increase in intraocular pressure. If not controlled, it can lead to optic nerve, retinal damage and blindness in the effected eye. KCS is a ocular disease that occurs when tear production decreases or ceases. It is known commonly as dry eye.
KCS is not seen frequently in cats but definitely in senior dogs. The animal is usually presented: squinting, inflamed conjunctiva, a green mucoid discharge over the eye and because of the irritation the dog will often paw at the affected eye. One eye or the other may be affected at the same time or at different times. Diagnosis is performing a Schirmer Tear Test Strip in both eyes. Normal tear production runs about 18-20. Borderline cases are about 12-16 and severe cases are often under 5. Depending on the severity of the condition, veterinarians will use tear supplements and or topical 1%-2% cyclosporine drops once a day. The latter is an immunosuppresent used in transplant medicine as well as skin conditions. In the eye, it stimulates tear production. Regular followups and Tear tests are recommended.
Glaucoma can be extremely painful. The fluid in the eye can not drain through the angle formed between the cornea and the iris. Depending on whether glaucoma being acute or chronic or primary or secondary, various clinical signs will be noted. A large painful eye, cloudy cornea, the iris attached to the lens or cornea, inflamed vessels in the whites of the eyes. Often one eyes is affected first but the second usually follows within a year or so. Diagnosis is made by using a tonometer which measures intraocular pressures. Treatment can be surgical or medical. Medical treatment often involves the use of mannitol, carbonic anydrase inhibitors that slow down eye fluid production and drugs that constrict the pupil making fluid drainage much easier. The best approach is to diagnose it early or better yet have your veterinarian perform tonometer tests each time your senior friend is taken to the veterinary office for a visit.