© 2009 by The Cat Clinic of Norman, P.C.

Senior and geriatric cats—that is, those over age 12—are far more likely than are younger cats to get a number of serious illnesses. However, age itself is not a disease.

Cats become more vulnerable to certain conditions as they age because the physiological changes associated with aging result in a reduction in the body’s ability to handle biological and environmental stressors.

The most common conditions affecting older cats are arthritis, cancer, dental disease, heart disease, hyperthyroidism, and kidney (renal) disease. This feline health article by Cat Clinic practice manager, Wendy Nelson, discusses each of these conditions, their symptoms and treatments.

ARTHRITIS

Arthritis is inflammation of a joint, in cats most commonly the elbow and hip. Causes include degeneration from aging, inherited condition, infection, injury, blood diseases, allergic or immune-mediated disease, and cancer.

Signs of arthritis include painful or stiff joint movement, joint swelling, and a grating noise during joint movement. However, cats tend to mask signs of pain and disability, so cat owners might first notice signs that are more general, such as reduced activity level, reluctance to jump or difficulty jumping, urinating or defecating outside of the litterbox, and reduced appetite.

Diagnosis is usually by radiograph and/or a physical exam. Radiographs can indicate arthritic changes but do not provide an assessment of pain. Thus, a radiograph might indicate severe disease, but the cat might not show signs of pain. The converse can also be true. Because cats mask pain so well, signs of arthritic pain might not be noticed except by a trained veterinarian.

Treatment focuses on managing symptoms and depends on the individual cat’s needs. Options include Cosequin supplement, fish oil supplements, massage/physical therapy, and pain medications. Cat owners can also make environmental changes to ease their cats’ symptoms. For example, a litterbox with low sides is often helpful because stepping over the sides of the box may be painful for the arthritic cat. Keeping a cat active will improve joint mobility and help maintain a healthy weight, both of which will ease arthritis symptoms. Heat therapy can alleviate pain and swelling, but we do not advise using electric heating pads because of the risk of burns and fire. The safest alternative is a hot water bottle or microwavable heat pad wrapped in a soft towel or blanket.

Although arthritis is not curable, controlling the symptoms and making a few simple environmental improvements can greatly improve your cat’s quality of life.

CANCER

Cancer is unrestrained cell division and growth. Cats are affected by a variety of types of cancer, but the most common ones in older cats are lymphoma, mammary cancer, and squamous cell carcinoma.

Lymphoma can occur in several locations but is most commonly seen in the intestines. It is the result of chronic inflammation, and symptoms include vomiting, loss of appetite, weight loss, diarrhea, and lethargy. (Many cat owners think vomiting is normal for cats. It isn’t. Chronic vomiting is a sign of illness and should always be addressed by a veterinarian.) Lymphoma is usually diagnosed through biopsy and evaluation of the suspect tissue by a pathologist. Treatment includes surgical removal of the diseased tissue and/or chemotherapy. Prognosis is generally good over the short term if the cancer is diagnosed and treated early.

Mammary cancer (essentially, breast cancer) occurs in the mammary glands and is far more likely to affect female cats (especially those who have not been spayed or who were spayed after their first heat cycle), although cases are occasionally reported in males. A mammary tumor feels like a firm lump and usually appears around the nipples. Large tumors can ulcerate and look like draining abscesses. Most mammary tumors are cancerous, and they grow rapidly, up to 1 cm per week. Because of this, cat owners should feel their cat’s abdomen monthly. For tumors smaller than two centimeters (about the diameter of a nickel), prognosis is significantly better than for larger tumors. Diagnosis usually requires radiographs. Treatment options are surgery and chemotherapy. If the tumor is small, short-term prognosis is good, but the cat may still have a decreased lifespan. Survival time for larger tumors is greatly decreased even with treatment. Tumors tend to metastasize to the lungs and lymph nodes. The best prevention is to spay a cat before her first heat cycle, at four to six months of age.

Squamous cell carcinomas are most commonly located on the skin of the face, nose, and ears, and in the mouth (particularly under the tongue). Sun exposure is the major risk factor for skin cancer, and thus white cats are particularly vulnerable to skin cancer. Risk factors for the oral form include exposure to cigarette smoke and flea collars, probably because the cat grooms the toxins off its coat. The skin form takes on many different appearances, and may look like a crusty sore, an ulcer, black lesions or crusts, or curling of the ears. The oral form is usually seen only on examination by a veterinarian. Signs of oral tumors include difficulty picking up or holding food in the mouth, drooling, decreased eating, and bad breath. Diagnosis is usually made through biopsy and evaluation of the suspect tissue by a pathologist. Squamous cell carcinoma is locally invasive and aggressive; it does not respond to chemotherapy or radiation, but it also metastasizes only infrequently. However, when it does metastasize, it tends to spread to the lungs and lymph nodes. Surgery is the only effective treatment, but the area that can be removed from the face or mouth is limited; so, early detection is crucial to survival. In addition to minimizing cats’ exposure to toxins (including second-hand smoke) and direct sunlight, people should regularly examine their cats for lesions and have their cats examined by a veterinarian every six months. Because most cats are resistant to oral examinations during a normal office visit, routine dental cleanings are important for spotting oral tumors, especially those under the tongue or deep in the mouth, before they grow large enough to cause the cat discomfort or difficulty when eating and drinking.

DENTAL DISEASE

Dental disease encompasses a variety of problems—periodontal disease, gingivitis, plaque, and tartar buildup. Dental disease is also implicated in diseases and failures of other organs, usually the kidneys and heart (once the bacteria that causes dental disease has done enough damage to gain access to the bloodstream, it circulates through the body and attacks the heart and kidneys). Thus, especially in older cats, maintaining proper dental health benefits not only the cat’s teeth but reduces the risk of developing heart and kidney disease.

Plaque is a film of bacteria, blood, cells, and saliva that covers the teeth. When plaque becomes hardened, it turns into tartar (sometimes called calculus), adheres to the enamel, and causes the gums to erode. Healthy gums protect teeth from periodontal disease (i.e., disease of the tissues that surround teeth). Gum damage can lead to more serious permanent damage to the tooth structure.

Gingivitis is inflammation of the gums (gingiva). Causes include bacterial and viral infections and foreign material such as hair, food, and plant material, as well as irritating substances. The most common cause is accumulation of dental plaque. Gingivitis is a progressive disease, and the early stages (slight reddening of the gum margin) are difficult to see. As the disease progresses, inflammation intensifies, soreness increases, gums may bleed easily, ulcers may develop, and breath worsens. Ulcers may appear in the gums, and untreated gingivitis frequently results in loss of teeth and more serious gum and tooth disease.

The normal groove around the base of the teeth, called the sulcus, is up to 3 mm deep; it provides an excellent pocket in which plaque can collect. Bacteria in the plaque cause soreness, swelling, and reddening of the gum line—opportunities for bacteria to go deeper, invading the delicate structures that house the tooth’s root(s). The assault on the gums and root structures eventually leads to periodontal disease.

Prevention is the key to maintaining good dental health. All cats should have regular dental exams and cleanings, which not only help preserve dental health but are important in helping to detect oral cancers before they become impossible to treat. The frequency of dental exams varies depending on the individual cat’s needs.

HEART DISEASE

The types of heart disease are many and varied, but among the most common heart problems in senior cats are arrhythmias, disturbances in the heart rhythm (beating too quickly, slowly, or irregularly) such that the heart is unable to continuously pump the necessary amount of blood.

Causes of arrhythmias include taurine deficiency, kidney disease, hyperthyroidism, inherited conditions, and toxin ingestion. Most high-quality cat foods contain the daily recommended amount of taurine, but cats eating a homemade diet will need a taurine supplement. Mild arrhythmias often have no apparent symptoms. Moderate to severe arrhythmias may cause reduced activity, trouble breathing during exercise, rapid breathing, coughing, abdominal bloating, and fatigue. Symptoms may appear irregularly, and sudden death may occur.

Diagnosis of an arrhythmia is usually made by listening to the heart and/or by electrocardiogram. Treatment depends on the underlying cause. If the arrhythmia is the result of a treatable condition, a cure might be possible. If the arrhythmia is the result of a congenital condition, a pacemaker might be needed to correct it.

HYPERTHYROIDISM

Hyperthyroidism is caused by excessive production and secretion of thyroid hormones. Signs include weight loss, increased appetite, hyperactivity, vomiting, diarrhea, and increased water consumption and urination. Cats with hyperthyroidism also frequently exhibit cardiovascular signs including increased heart rate, arrhythmias, and congestive heart failure. Untreated hyperthyroidism can lead to enlargement of the heart and high blood pressure. Treatment options include medication, surgical removal of the thyroid gland, and radioactive destruction of the thyroid gland.

The medication for hyperthyroidism has some potentially serious side effects, and it must be given for the rest of the cat’s life.

Destruction of thyroid tissue by radioactive iodine is widely considered the gold standard for treatment, but it is expensive, requires the cat to be confined at the treatment facility until the radiation leaves its body, and exposes the cat’s systems to radiation.

Removal of the thyroid by a skilled surgeon is as effective as radioiodine therapy, with comparable risk, and is often the most economical treatment choice. In choosing which treatment to pursue, the needs and risks of all options must be evaluated on an individual basis.

Hyperthyroidism can mask damaged kidneys by increasing the blood pressure and filtration rate in the kidneys, thus compensating for kidneys that might otherwise not be functioning properly. Because of this, close monitoring of kidney function is essential while a cat is hyperthyroid and after treatment returns thyroid levels to normal. Only when thyroid function is normalized can kidney function be accurately assessed.

KIDNEY (RENAL) DISEASE

Older cats are vulnerable to renal disease because of the accumulation of insults (toxin exposures, infection, blood pressure fluctuations) over the years. Among the most common dangers to cats’ kidneys are antifreeze/radiator coolant; aspirin and ibuprofen; dental disease; high or low blood pressure; copper; and many toxic plants, including lilies.

Damaged kidneys lose some of their filtering ability; so, waste products accumulate in the bloodstream while water is lost, causing chronic dehydration. Continued recirculation of waste material and dehydration results in illness. By the time clinical signs appear, including detectable blood value changes, cats have usually lost 50–65 percent of their renal function.

Fortunately, because cats (like people) can live with only one kidney, even with a 50 percent loss of kidney function, they can live a fairly normal life. However, renal disease must be kept under control. Unlike the liver, the kidneys have limited repair ability.

Signs of chronic kidney disease include vomiting, constipation, increased thirst, increased urination, decreased appetite, depression, oral ulcerations, and bad breath. Untreated illness can result in seizures, coma, and death. Although chronic kidney disease is not curable, it is often controllable through diet and medication.

An example of squamous cell carcinoma of the skin (nose)