Hyperthyroidism means elevated thyroid hormone. The term assumes that the elevated thyroid level is coming from the thyroid gland (and not from thyroid pills). There are three causes of hyperthyroidism. The first is thyroid nodules. Many people have thyroid nodules. Sometimes the nodules will make excessive thyroid hormone. The second cause is Hashimoto’s disease or thyroiditis. Hashimoto’s disease typically causes hypothyroidism, but in some patients when the inflammation of Hashimoto’s (thyroiditis) first hits a normal gland it causes the hormone that’s been stored up in the gland to spill out. This can cause a temporary hyperthyroidism that will go away by itself. The hyperthyroidism can last a few months.
The third cause is Grave’s disease, which is the classic form of hyperthyroidism. Grave’s disease, like Hashimoto’s disease, comes from the body’s immune system, in which case it accidentally makes antibodies against the thyroid gland. In Hashimoto’s disease those antibodies attack and destroy the gland. In Grave’s disease the antibodies actually stimulate the gland to grow and to make too much thyroid hormone. Since antibodies usually don’t go away, Grave’s typically does not go away. It only spontaneously resolves in about 8% of patients.
The typical symptoms of hyperthyroidism are fatigue, insomnia (“tired but wired”), heart palpitations, heat intolerance, increased sweating, feeling shaky, jittery, increased anxiety, weight loss, and increased bowel movement frequency. Everyone’s body is different in how it responds to abnormal thyroid levels. Some patients get all of these symptoms and some patients get none. Some patients get totally different symptoms than these “text book” ones. About 20% of patients with Grave’s disease get Grave’s eye disease. In this case the antibodies get into the tissue around the eye. This can cause irritation, swelling around the eyes, bulging of the eyes, or interference with the muscles that move the eyes. Grave’s eye disease is more common in patients who smoke.
There are different options for the treatment of hyperthyroidism. If the hyperthyroidism is mild and you have no symptoms you do not need treatment unless you are over 65 years old or have heart disease. If I recommend treatment I usually recommend medication. The most commonly prescribed medication is methimazole. If a patient does not tolerate medication I may recommend radioiodine ablation. Very few patients need to have the thyroid gland surgically removed.