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Hyperthyroidism in Pets

  • In cats, hyperthyroidism results from functional thyroid adenomatous hyperplasia (growth of the glandular cells) or adenoma (a benign tumor). Rarely, a cancerous tumor (adenocarcinoma) causes feline hyperthyroidism. One or both lobes of the thyroid gland are involved (70 percent of cases involve both thyroid glands). Most cats with hyperthyroidism are ten years of age or older.

    The most common clinical signs include hyperactivity, weight loss, increased appetite, vomiting, or diarrhea. In some cases (apathetic hyperthyroidism, which occurs in approximately five percent of cases), the cat does not experience these classic signs. Instead, the cat may act more lethargic, eat less, and generally act depressed or weak.

    Diagnosis is made by finding elevated thyroid hormone levels on a blood profile. Other common geriatric diseases whose clinical signs mimic hyperthyroidism, such as kidney disease and diabetes, should be screened for as well. Secondary problems such as mild liver or heart disease usually resolve when the underlying hyperthyroidism is treated. Because older cats can also have kidney disease that may worsen if the hyperthyroidism is treated, cats with hyperthyroidism must be carefully screened for kidney disease prior to treatment of hyperthyroidism.

    Principal Natural Treatments
    Glandular Therapy—is recommended for cats. It uses whole animal tissues or extracts of the thyroid gland. Current research supports this concept that the glandular supplements have specific activity and contain active substances that can exert physiologic effects.

    While skeptics question the ability of the digestive tract to absorb the large protein macromolecules found in glandular extracts, evidence exists this is possible. Therefore, these glandular macromolecules can be absorbed from the digestive tract into the circulatory system and may exert their biologic effects on their target tissues.

    Several studies show radiolabeled cells, when injected into the body, accumulate in their target tissues. The accumulation is more rapid by traumatized body organs or glands than healthy tissues, which may indicate an increased requirement for those ingredients contained in the glandular supplements.

    In addition to targeting specific damaged organs and glands, supplementation with glandular supplements may also provide specific nutrients to the pet. For example, glands contain hormones in addition to a number of other chemical constituents. These low doses of crude hormones are suitable for any pet needing hormone replacement, but especially for those pets with mild disease or those whom simply need gentle organ support.

    Glandular supplements also function as a source of enzymes that may encourage the pet to produce hormones or help the pet maintain health or fight disease. Finally, glandular supplements are sources of active lipids and steroids that may be of benefit to pets. The dosage of glandular supplement varies with the product used.

    Astragalus—is used to strengthen the immune system and acts as an antibacterial and anti-inflammatory herb. As a result, many doctors prescribe this herb for pets with various infections and for those with chronic illnesses, including cancer.

    In cats, astragalus is often recommended for the treatment of hyperthyroidism. It can also be used to help the body recover from long-term steroid therapy and for pets with kidney disease, as this herb improves kidney circulation.

    Astragalus membranaceous is safe, but other species of astragalus can be toxic. Do not use in pets with diseases resulting from an overactive immune system (autoimmune diseases).

    Bugleweed—may be useful for cats with mild hyperthyroidism. Frequent doses of the herbal extracts must be given for several days before any result may be detected. Like digitalis, bugleweed can be helpful in heart conditions in which the heart's contractions should be strengthened and the rate (pulse) decreased.

    Bugleweed can also act as a diuretic and remove excess fluid from the lungs, as might occur in congestive heart failure. It can be useful for pain relief and does not contain salicylic acid so it can be used safely in cats. Do not use in pregnant animals.

    Lemon Balm—may be useful in cats to decrease thyroid output and possibly decrease blood pressure. As with the other herbs mentioned, controlled studies are hard to find, and herbs may not be helpful in cats with severe disease. The dosage of herbs varies with the product used.

    Other Natural Treatments
    Other therapies include homeopathies (homeopathic tyhyroidium), and whole food supplements. Use raw broccoli mixed in a homemade diet, as much as possible; or if the cat does not eat raw broccoli, use a whole food broccoli supplement such as Phytolin from Standard Process.

    These can be used in conjunction with conventional therapies, as they are unlikely to be effective by themselves in most patients. The natural treatments are widely used with variable success but have not all been thoroughly investigated and proven at this time. As with any condition, the most healthful natural diet will improve the pet's overall health.

    Safety Issues
    Because vegetables such as broccoli and cabbage can depress thyroid hormone if eaten in large amounts, they should not be fed (or fed in only in small amounts) to dogs with hypothyroidism. The herbs mentioned above, while useful in treating cats with hyperthyroidism, should be avoided in dogs to prevent a worsening of clinical signs. Treatments to avoid in dogs include astragalus, bugleweed, and lemon balm.

    Conventional Therapy
    Three conventional therapies are recommended for cats with hyperthyroidism. Surgical removal of the thyroid gland can be performed. However, anesthesia is needed for this procedure; and while geriatric cats can be safely anesthetized, the other options for treatment usually do not require anesthesia and are usually preferred. Second, surgery, especially in severely hyperthyroid cats, is associated with significant morbidity (illness and trauma) and mortality, as well as the chance for postoperative calcium imbalances due to damage or inadvertent removal of the associated parathyroid glands.

    Medical therapy, most commonly with methimazole (Tapazole), is another conventional option. The medicine is given for the life of the cat and is very successful in lowering levels of thyroid hormones. Rare side effects include lack of appetite, vomiting, lethargy, facial dermatitis, and low red cell, platelet, and white blood cell counts. Liver disease is also a possible side effect. Cats experiencing abnormal blood or liver profiles or facial dermatitis are at risk of future serious side effects and must have their medication stopped and another form of treatment instituted.

    The third and most commonly used treatment for cats is radioactive iodine. While this sounds quite drastic, it may be the safest conventional treatment for hyperthyroid cats. Side effects are extremely rare, and most cats are completely cured after one treatment. Hypothyroidism, or low thyroid output, is a rare side effect of treatment that can easily be treated with thyroid replacement hormone if needed. Because radioactive iodine cures the hyperthyroid conditions, and because cats with underlying kidney disease could develop kidney failure when cured of their hyperthyroid conditions, it is essential that cats be screened for kidney disease prior to radioactive iodine treatment. The major concern among owners is that cats treated with radioactive iodine must be hospitalized for one week or more until they are no longer excreting radioactive iodine in their urine or feces.

    A fourth, newer proposed treatment is injection of ethanol directly into the affected thyroid gland using ultrasound to guide the procedure (percutaneous ethanol ablation). Early studies appear positive, although some cases involved laryngeal paralysis secondary to leakage of ethanol from the thyroid gland and inflammation of the recurrent laryngeal nerve. More research is needed to determine whether percutaneous ethanol ablation will become a safe and effective therapy for treating feline hyperthyroidism.

  • Dear Readers,

    Welcome to the January 2018 issue of TotalHealth Magazine Online.

    Dallas Clouatre's, PhD, article, "Probiotics For Digestive Health," answers many questions on probiotics, what they are, why we need them and how to select them. Best described by the following quote: {For instance, according to Tim Spector, professor of genetic epidemiology at Kings College London and director of the British Gut Microbiome project, a "healthy gut is like a perfect English garden. You've got a diversity of microbes of all types, all living together and feeding off each other's byproducts—nothing is wasted."}

    This is part two of a two-part series on Coenzyme Q10 (See part one TotalHealth December 2017 page 10) titled "Coenzyme Q10: The New Era," by Ross Pelton, RPh, CCN and William V. Judy, PhD. "Coenzyme Q10's dual functions (antioxidant & energy production) make it essential for the health of virtually all human tissues and organs. As a fat-soluble antioxidant, it protects proteins (like LDL-cholesterol), enzymes, fats (all cell walls/membranes) and especially DNA from free radical damage. In terms of energy production, areas of the body with high rates of metabolic activity (high energy demands) such as the heart, lungs, kidneys, brain and immune system are especially sensitive to low levels of CoQ10." Read on for the full update.

    Ann Louise Gittleman, PhD, CNS, in "Bile: Your New BFF," brings an important and not often discussed system of the workings of the human body. Bile is produced by the liver to the tune of about one quart per day, bile is made from lecithin, cholesterol and bilirubin. The body stores it in the gallbladder, and moves it to the intestines during digestion. After reading about the process you'll understand why Gittleman refers to it as your new best friend forever.

    "Optimizing Cognitive Function—Foods And Supplements," Jacob Teitelbaum, MD, describes our brain as our body's motor. Our brain consumes 10 times as much energy for its size as the rest of our body. "So what we feed it determines whether it purrs like a Ferrari, or runs in fits and starts." Teitelbaum includes the top four foods and supplements to feed your brain.

    Elson Haas, MD, in this month's article, "A Smart Start To Your New Year The Health Benefits Of Seasonal Detox," emphasizes detox approach to improving your health. Haas has been leading and participating in detox programs during his thirty-one years in medical practice. This Detox program begins in January 2018.

    Gene Bruno, MS, MHS, RH(AHG), "Complementary And Alternative Treatments for Seasonal Allergies," describes what many of us experience as a congested, runny, itchy nose together with frequent sneezing and watery eyes that makes you feel miserable. If you are looking for a complementary and alternative treatment approach to allergies look no further. Bruno describes a full menu of supplements available to you.

    Gloria Gilbère's, CDP, DAHom, PhD, presents "Apple Cider Glazed Chicken with Sweet Potatoes." Inflammation-free, nightshade free recipes, there are many ways by which normal cells and tissues can be damaged, leading to inflammation. One important way is consuming nightshade foods because they contain a substance known to accelerate inflammation—Solanaceae or Solanine—alkaloid chemicals that can be highly toxic.

    Shawn Messonnier, DVM, consults this month on, "Hyperthyroidism in Pets." Reminding us to always consult with our veterinarian before supplementing our pets' diet.

    Best in health,

    TWIP The Wellness Imperative People

    Click here to read the full January issue.

    Click here to read the full January issue.