The Facts About Hyperthyroidism And Hypothyroidism

I am 28 yrs old and was diagnosed with hyperthyroidism. Is this normal for a female? Please let me know everything you know about this disease.

I have been diagnosed with hypothyroidism, specifically Hashimoto’s thyroiditis. I have very large eyes, similar to what one would see with Graves’ disease. I don’t understand how I could have a symptom of hyperthyroidism and yet suffer from lack of thyroid hormone. Do you have any insights?

I receive many letters about hyperthyroidism, (overactive thyroid), and hypothyroidism (underactive thyroid), and have picked these two as representative.

Hyperthyroidism with an enlarged thyroid gland (located in the lower part of the neck) and prominent or protruding eyes, is called Graves’s disease. It is considered an autoimmune disease, as antibodies formed by the person produce stimulation of the gland, causing the release of excessive amounts of the two thyroid hormones, referred to as T4 and T3.

As is seen with all autoimmune diseases, women are more commonly affected than men. The condition may run in families, or other family members may have other autoimmune diseases such as pernicious anemia, Sjogren’s syndrome, rheumatoid arthritis, lupus and Hashimoto’s thyroiditis, itself an autoimmune disease and the most common cause of hypothroidism. Graves’ disease is most commonly seen in 20- to 40-year-olds.

Hashimoto’s disease is an inflammation of the thyroid gland, a thyroiditis, which is also caused by antibodies directed against the gland. In this case, however, instead of causing prolonged overproduction of thyroid hormones, the autoantibodies eventually destroy the gland, preventing it from producing the hormones, and therefore producing permanent hypothyroidism. The picture can be complicated by the fact that occasionally the inflammation causes the release of enough of the hormones stored in the gland that it will produce a temporary state of hyperthyroidism. This is usually mild, should not cause bulging or protruding eyes, and is inevitably followed by hypothyroidism because of the destruction of the gland.

Why some people will produce autoantibodies which stimulate the gland and cause hyperthyroidism, while others produce autoantibodies which slowly destroy the gland and produce hypothyroidism, is not known.

Both conditions are readily treated. Hypothyroidism requires simply the replacement of the missing thyroid hormones. Most doctors these days choose a synthetic form of T4 called L-thyroxine (Synthroid is a brand name). Some T4 is transformed in the body into T3, so taking only the one hormone replaces both for most people. There is a “natural” hormone called thyroid extract, derived from the thyroid glands of cattle, which used to be widely used, but because it could not be standardized as easily as T4, it is now seldom prescribed. There are no plant or herbal sources of these hormones that I am aware of. Taking iodine in vitamins or as separate pills will not treat hypothyroidism, since the problem lies not with the supply of iodine, but with the body’s ability to form it into the hormones T4 and T3. In fact excessive iodine can be harmful in some situations.

The treatment of Graves’ disease is more complicated, and may involve pills, radioactive iodine or, occasionally, surgery. I have discussed this in more detail in the past.

Our second writer today mentions having large eyes, and being confused since this occurs with Graves’ disease, but not with Hashimoto’s disease. I’m not clear whether she has always had large eyes, in which case that is simply the way her face is formed, or whether they began protruding recently. If they have changed recently then her doctor should consider other rare conditions which can cause the eyes to protrude. An MRI scan might be helpful to distinguish between the swelling and enlargement of the eye muscles seen in Graves’ disease, and the other less common causes of protruding eyes.

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