Feline Hyperthyroidism is a relatively common disease of older cats. These cats tend to lose weight despite having a good appetite. This is a treatable condition.
The following symptoms are usually seen in cats with hyperthyroidism:
Many cats with hyperthyroidism will have a thyroid gland that can be felt by your veterinarian. However, it can often be difficult to feel this gland. If your vet suspects feline hyperthyroidism they will do a blood test called a T4 level. They will likely also do a geriatric blood screen including kidney and liver enzymes. Cats with hyperthyroidism can sometimes have other health issues. Also, other diseases that affect older cats such as diabetes or kidney disease can look similar to hyperthyroidism.
There are three types of treatment that veterinarians currently use for cats with feline hyperthyroidism, radioiodide therapy or a medication called methimazole (Tapazole and Felimazole), and using a food called Hill's y/d.
This is probably the better treatment for most cats. However, it can be expensive. In radioiodide therapy the abnormal thyroid tissue is destroyed with radiation. It is a safe treatment for the cat and not painful. However, because there is radiation involved, the cat usually needs to be hospitalized in a special facility for about a week.
Most cats who have had radioiodide therapy do not need any further treatment for hyperthyroidism. However, occasionally a cat will need a small dose of medication to maintain a normal thyroid level
Most people in my practice opt for medical therapy simply because it is less expensive. A medication called methimazole (tapazole or felimazole) is given once or twice daily. This is a very small pill that is given. Your cat will need this medication for the rest of his or her life.
About 2-4 weeks after starting the medication your vet will do another T4 blood level to determine if we are giving enough (or too much) medication. Once the T4 level is where we want it to be your vet will want to do the T4 test either every 3, 6 or 12 months. It is important to follow your vet's advice on doing this testing because cats who have abnormal T4 levels can have serious health problems as a result.
Your vet may also want to do some additional tests on your cat's kidneys as the thyroid level starts to stabilize. Some cats will develop kidney disease as the thyroid level comes back to normal. Your vet may also want to check your cat's blood pressure and check his or her heart periodically. Cats with hyperthyroidism often have heart disease or high blood pressure. If this goes untreated, the cat can develop a condition called retinal detachment which can cause permanent blindness. It is also very uncomfortable for a cat to have high blood pressure. It is theorized that some geriatric cats who howl at night time do so because they have a headache that is caused by high blood pressure!
Introduced in the fall of 2011, Hill's y/d may be a revolutionary treatment for hyperthyroidism. This treatment is discussed here.
Dr. Marie was quick to respond and thorough in suggesting treatment for my cat. I am so thankful- I have been so worried about my cat. Now I have additional options to discuss with my vet.
The service was incredibly fast and the vet's suggestions were right on target. This was incredibly helpful given that none of the vets in my area, mine now included, will take off hours calls now.