Hyperthyroidism is the most common endocrine disorder in cats. Thyroid disease (hyperthyroidism) in cats results from excessive production of hormones from the thyroid gland. In most cases, this is caused by a single mass or multiple masses on the thyroid gland. 

Kitties typically do not present to the veterinary hospital because the pet family has felt one of these thyroid nodules. The nodules are very small and not in a place that people typically pet/touch. Most commonly, when a kitty is first diagnosed with thyroid disease, they typically have one or more of the following clinical signs: weight loss, muscle mass loss, increased appetite, restlessness, hyperactivity, hair coat changes, vomiting, diarrhea, increased drinking, increased urination. Less commonly, we will see lethargy, weakness, and decreased appetite, but although less common, it will sometimes occur. Some cats do show aggressive behavior that typically does resolve in response to successful treatment of the “hyperthyroid state.”

Blood work, such as complete blood count & organ function profile, tend to be fairly normal. When there are abnormalities seen, typically, they are with the kidney and liver values. Urinalysis may show mild changes but also tends to be close to the baseline. Typically diagnosis is made with a T4 or free T4, in combination with the right clinical signs (mentioned above) and palpating a thyroid nodule. 

Western Approach to Hyperthyroidism

There are several treatment options in the traditional approach:

1. Anti-Thyroid Drug – The goal of these drugs is to “control” a kitty’s hyperthyroidism, and these medications need to be administered daily in order to maintain this effect. These drugs can be administered by mouth or transdermally (rubbed in the ear pinnae). The common drugs are – methimazole, propylthiouracil & carbimazole. The most common drug used is methimazole, and this can be administered orally or transdermally. 

2. Prescription Diet – The goal of the food is to “control” a kitty’s hyperthyroidism and needs to be eaten daily in order to maintain this effect. 

3. Radioactive Iodine – The goal of this therapy is to provide a permanent cure. This treatment causes the destruction of functioning cells of the thyroid. The atrophied (shrunken) normal cells are not destroyed, which prevents the majority of cats from becoming hypothyroid (low thyroid hormone). Most cats within 3 months will have a normal T4 (so normal functioning thyroid), and the majority of cats in 1-2 weeks will have a normal T4 after the treatment. 

4. Surgery – The goal of this surgery is to provide a permanent cure. Since the development of the radioactive iodine treatment, this is rarely used anymore.

There are many factors that need to be considered when choosing one of these western options, such as overall health, kidney function, and any other current disease (heart disease, GI disease, etc.). Typically cats are started on anti-thyroid drugs or food in order to assess the impact treatment will have on kidney function. Unfortunately, when we treat thyroid disease, we can often unmask kidney disease, so monitoring the kidney values can be important. As the T4 returns to normal with anti-thyroid drug treatment, if kidney values remain stable and overall the cat is in good health, the pet parent can then pursue a more permanent treatment, like radioactive iodine. 

Eastern Approach to Hyperthyroidism

There are 4 branches of Traditional Chinese Veterinary Medicine – Food Therapy, Acupuncture, Herbal Medications, and Tui-Na. Obtaining a Chinese Medicine diagnosis involves determining a “pattern” for the patient based on their clinical signs, history, and personality/constitution. Even though all of these cats would have the same Wester diagnosis, they may have different Chinese patterns present. There are 4 common patterns associated with hyperthyroid kitties.

1. Herbs – Herbal formulas can be very safe and effective at helping to make the body stronger and create internal balance. Similar to the western anti-thyroid drugs- they are not going to cure hyperthyroidism. They can definitely reduce clinical signs that are associated with the hyperthyroid disease state, reduce the size of the mass or masses, and lower thyroid hormone being secreted, but they are not going to completely eliminate these masses or the hyperthyroidism.  There are two common formulas that address the two different “patterns” that are most commonly associated with hyperthyroidism. 

2. Acupuncture – This can definitely add to the balance of the body. It is great as part of a pain management plan (bone/soft tissue etc.) Acupuncture is going to have a much bigger impact on decreasing inflammation, pain management & tissue healing. Acupuncture can definitely help with internal balance, but it is not going to have as big of an impact as it does with the musculoskeletal / mobility piece. Acupuncture & herbs together can act synergistically. So rather than 1+ 1 = 2, the equation will look like 1+ 1 = 4. But acupuncture will not be able to cure Hyperthyroidism. 

3. Food Therapy is the use of diet to treat and prevent imbalance within the body. It utilizes knowledge of the energetics of food ingredients to tailor diets for individual animals. This can definitely be used to help balance the body as a whole based on the underlying pattern.

4. Tui-Na – Hampton Roads Veterinary Hospice will have two of our doctors certified in Tui-Na by early 2022. Tui-na is a form of Chinese medical massage that stimulates acupuncture points and Meridians to promote the circulation of Qi and correct imbalances within the body. While it likely would help the treatment options mentioned above, it alone would not have a significant impact on hyperthyroidism.