Understand Hashimoto’s Thyroiditis and its treatment

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DEAR DR. ROACH: Please explain Hashimoto’s disease. I have heard that it is rare, but two colleagues have recently been diagnosed. We all work in a very high-stress field. – J.H.

ANSWER: Hashimoto’s thyroiditis is not at all a rare disease. It occurs in up to 10% of the population and much more frequently in women than men. Although people can be diagnosed at a young age, it is more common at older ages. It is caused by an autoimmune reaction to different parts of the thyroid, with thyroglobulin and thyroid peroxidase antibodies commonly found. TSH receptor antibodies are found on occasion.

Hashimoto’s thyroiditis most commonly causes low thyroid levels, although there may be a period of time early in the disease where thyroid levels are high. Not everybody with antibodies will develop low thyroid levels. The thyroid is sometimes enlarged, but a careful exam will usually show that the gland is firm, showing that immune cells have infiltrated the gland.

Treatment of Hashimoto’s thyroiditis involves replacing the thyroid hormone that the gland can no longer make. The dose depends on body size to a certain extent, but needs to be adjusted based on lab results. Most people are treated with levothyroxine, also called T4, which is the primary hormone made by the thyroid.

T4 is converted to T3 (also called triiodothyronine, the active form of the hormone) in various tissues outside the thyroid. T3 only stays in the body for a short while before it is destroyed, so a once-daily treatment with T4, which lasts longer, allows the body to convert T4 to T3.

Most people do very well with T4 treatment. A minority of people cannot efficiently make the active T3 form, in which case-combination treatment can be considered. Unfortunately, T3 must be dosed twice daily.

It is thought that stress hormones play a role, since stress does seem to increase the risk of developing an autoimmune thyroid disease like Hashimoto’s.

DEAR DR. ROACH: Huntington’s disease runs in my family; my brother and sister started having symptoms in their early 60s. I am 80 and don’t have any symptoms. Can I assume that I don’t have it? I hear testing can be expensive. Are there any organizations that test for free? – S.B.

ANSWER: Huntington’s is a progressive, degenerative neurological disease that causes abnormal body movements, psychiatric changes and dementia. The movement disorder, called chorea, is the first symptom. It can begin very slowly, and people may not be aware of it. A careful exam can show the characteristic findings. A movement disorder specialist is the ideal person to see in this case.

It would be very unusual to begin having symptoms at, or after, the age of 80, so it is very likely that you do not have the disease if you don’t have any symptoms and have received a normal exam by an expert.

Testing should be performed only after careful consideration and counseling by an expert such as a genetic counselor. According to the Huntington’s Disease Society of America (see tinyurl.com/HDgenetictesting), testing can cost between $315-$1,500, but it is often covered by insurance. Free testing may be available as part of a research study.

Dr. Roach regrets he is unable to answer individual questions, but he will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu.