Dear Sinéad, Siouxsie and Thomas:
I have a 12 year old cat named Chicklet and would like to know about hyperthyroidism. Is it a disease? What are the symptoms?

Thank you,
Es

Thomas: This is an interesting question, Es, and we're glad to have the opportunity to talk about hyperthyroidism.

Sinéad: First, let's start with some information about what the thyroid gland is, where it's located, and what it does. The thyroid gland is a vaguely H-shaped (or butterfly-shaped, if you like animal imagery better) organ located at the base of the neck, just below the voicebox. All mammals have a thyroid gland, including humans.

Siouxsie: The thyroid gland manufactures and secretes two hormones, thyroxine and triiodothyronine, which help to regulate the body's metabolism. The metabolism is the rate at which the body turns food and oxygen into energy.

Thomas: Vets aren't sure why, but sometimes middle-aged or senior cats' thyroid glands become enlarged and develop tumors called nodular goiters. The enlarged thyroid produces too much thyroid hormone into the body, and this causes an array of symptoms.

Sinéad: First, all those metabolic increase hormones cause the body to burn food and oxygen too fast. Because of this, a hyperthyroid cat loses weight and is always hungry because his body is burning up food faster than he can eat it. His behavior changes, too, and he can become cranky or hyperactive.

Siouxsie: Other symptoms of hyperthyroidism include increased drinking and urination; pacing; howling or yowling; oily coat, hair loss and/or rapid claw growth; diarrhea or vomiting; and seeking a cool place to rest (because a hyperthyroid cat's overstimulated metabolism makes him feel too hot).

Thomas: Hyperthyroidism is considered a disease. Most standard vets believe it's idiopathic -- not caused by anything known or obvious -- in origin. Holistic veterinarians, on the other hand, tend to believe that hyperthyroidism may be due to poor diet and overvaccination.

Sinéad: Whatever the cause, apparently the risk factors for developing hyperthyroidism include being fed a predominantly canned-food diet, especially if the food contains giblets. The giblets are the heart, liver, gizzard, and other organs of a bird. Although they are quite yummy, organ meats tend to store toxins and hormones, so maybe that's part of the reason these meats could contribute to disease. Another risk factor seems to be exposure to cat litter -- but how can a cat not be exposed to cat litter?

Siouxsie: Maybe what they mean by "cat litter" is the stinky, nasty cat litter that some humans seem to think smells good. All those artificial fragrances and chemicals can't be good for our little kitty bodies!

Thomas: Even Mama thinks those "freshness-flavored" cat litters are gross. They make her sneeze, too.

Sinéad: Something you should be aware of is that cats with hyperthyroidism also tend to have high blood pressure and kidney function problems. This makes sense when you think about it. A cat with a too-high metabolic rate develops elevated blood pressure, and, as with humans, high blood pressure causes damage to the kidneys (and other organs, of course). So if your cat has hyperthyroidism, your vet will also check Kitty's kidneys and blood pressure.

Siouxsie: Hyperthyroidism is usually discovered through a blood test. Most vets will want to do periodic blood tests on senior cats (age 8 or older). These blood tests measure the levels of certain hormones associated with the function of the liver, thyroid and kidneys. If these levels are too high or too low, the vet will order further tests.

Thomas: When a blood test shows that a cat's thyroid hormone levels are too high, vets will order another diagnostic test called scintigraphy, or thyroid scan. This test involves injecting the cat with a liquid containing a radioactive particle that seeks out and attaches to thyroid tissue. Then the cat is scanned with a gamma camera, which shows where in the cat's body the thyroid tissue is.

Sinéad: This may seem weird, because we already said that the thyroid gland is in the throat. But if the hyperthyroid condition is caused by a cancerous tumor, the cancer could have spread to other parts of the body and be growing thyroid-type tissue far away from the real thyroid gland.

Siouxsie: But anyway, the results of the scintigraphy will help the vet to figure out which treatment option is best for the hyperthyroid cat.

Thomas: The good news is that hyperthyroidism is a highly treatable disease. There are three treatments that veterinarians use for hyperthyroidism. The treatment that is used depends on the results of the scintigraphy.

Sinéad: If the thyroid condition is caused by a tumor in the neck, surgery is the typical treatment. Sometimes the vet will remove only the part of the gland where the tumor is located. Most vets will prefer to remove the whole gland, though, so they don't have to go back and do another operation later if the remaining thyroid gland develops a tumor.

Siouxsie: Most cats seem to recover just fine from this surgery, and although a few may need to take thyroid hormone supplements after surgery, most don't.

Thomas: Another treatment option is a drug called Tapazole (generic name methimazole). This drug suppresses thyroid hormone production, but it doesn't make the problem go away. Sometimes vets will prescribe Tapazole until another treatment, such as surgery or radioactive iodine, can be scheduled. Tapazole is usually given as a pill (which you have to give to kitty twice a day), but the drug can also be compounded into a cream or gel that you can rub into the skin on the inside of their ears.

Sinéad: There is a problem with Tapazole, though. About 20% of the cats treated with this drug have a bad reaction. They can develop liver disease, blood problems or chronic itching. Also, because the tumors continue to grow, a cat receiving this medication will need to have more and more as time goes on.

Siouxsie: The third treatment commonly used for hyperthyroid cats is radioactive iodine treatment. This is a one-time-only treatment, but it isn't usually available to people living far from cities with major veterinary schools or research clinics. The radioactive iodine is injected into the cat's bloodstream and the iodine targets the tumor cells.

Thomas: How does this work? Iodine is key to thyroid function, and humans discovered, through doing things like blowing up nuclear bombs near populated areas and dealing with accidents like meltdowns and explosions at nuclear power plants, that a radioactive iodine molecule could also get into the thyroid gland easily. The radiation in that iodine molecule then killed the cells in the thyroid gland.

Sinéad: So this discovery has now been turned into a treatment used to kill tumor cells that are producing too much thyroid hormone.

Siouxsie: There is one little drawback with this treatment. Since the cat is injected with radioactive substances, he actually becomes radioactive! Because of this, cats receiving radio-iodine therapy need to be quarantined for a period of time ranging from five days to a month, depending on state laws. That's how long it takes for most of the radioactive particles to be excreted from the cat's body.

Thomas: A few cats become hypothyroid -- that is, their thyroid glands become underactive because the iodine killed too many thyroid hormone-producing cells -- after the treatment and need to be put on thyroid supplements, but that's rare.

Sinéad: So that's hyperthyroidism in a nutshell, according to standard veterinary medicine. Now we'd like to talk a little bit about complementary or holistic medicine and how combining holistic medicine with standard veterinary care can help you manage hyperthyroidism without resorting to surgery or radiation treatments.

Siouxsie: If your cat is diagnosed with hyperthyroidism because of a routine blood test, and his thyroid values are just slightly elevated, most vets will be OK with adopting a "wait and see" approach and monitoring the cat's thyroid levels at monthly or bimonthly intervals. Even if your vet prescribes medication for your cat's hyperthyroidism, we still think it can't hurt to combine holistic care with standard veterinary treatment.

Thomas: A holistic veterinarian may be able to help you adopt a program of nutritional therapy and other treatments, such as homeopathy, acupuncture or herbalism. As we said earlier, one of the major risk factors for hyperthyroidism seems to be the consumption of mostly canned cat food. This speaks to the idea that changing your cat's diet could help his body move toward a more balanced and healthy state.

Sinéad: More and more veterinarians are either adding holistic medicine to their conventional veterinary treatment repertoire, or switching over from traditional "allopathic" medicine to a completely holistic care modality. They are doing this because they see that holistic care can effectively manage illnesses that conventional veterinary medicine can't really treat without causing more problems.

Siouxsie: Please note that we are not suggesting that you use holistic treatment instead of regular veterinary care! Holistic medicine is referred to as "complementary medicine" for a reason: It complements the care offered by your regular "conventional" veterinarian. It does not replace such care.

Thomas: And if you do seek holistic care, make sure you do your research on the treatment a holistic practitioner offers. Some "treatments" may be ineffective ... or worse, actually harm your cat's health.

Sinéad: It's unfortunate but true that there are people out there who are in the business of selling false hope to make a quick buck. So before you embark on a treatment, please check it out and decide for yourself, based on real results rather than hype and testimonials (which can be bought and paid for, or even completely fabricated).

Siouxsie: There are a few ways you can find a legitimate holistic veterinarian in your area. The first of these is to ask your veterinarian if he or she knows of a holistic vet in your area. If you live in a rural state, you may have to look farther to find one, but they are around.

Thomas: You can also ask holistic health practitioners who serve humans. Often these individuals will know of holistic animal care providers, too. Also, you can look in magazines or newspapers that are oriented toward holistic health for people; sometimes holistic vets will write articles for or advertise in these publications because many people who seek out holistic care for themselves also like to use such treatment for their animal companions.

Sinéad: Another resource for finding a holistic veterinarian is the American Holistic Veterinary Medical Association. Their website has information about the organization and a state-by-state director of holistic animal care providers. Mama says their directory may not be all that up-to-date, but it's worth checking out anyway.

Siouxsie: We hope we've answered your questions, Es. If you want any more information, please feel free to e-mail us and ask. If your Chicklet has hyperthyroidism, remember that the prognosis is hopeful. The disease can be effectively treated, and you can enjoy many more healthy and happy years with your kitty.

Got a question? Need some advice? E-mail Sinéad and Siouxsie at advice@paws-and-effect.com. None of the advice in this column is meant to be a substitute for regular veterinary care.