The thyroid gland produces hormones, such as thyroxine, that regulate the body's metabolism. Two main types of thyroid hormone disorders exist: hypothyroidism and hyperthyroidism. If a person has hypothyroidism, her thyroid does not make enough hormones, which can lead to obesity, a lack of energy, and heart problems. Hyperthyroidism occurs when a person's thyroid makes too much of the thyroid hormones, leading to weight loss, an irregular heartbeat and excessive sweating.
Several other conditions can lead to thyroid hormone disorders. In some cases, treatment for one type of thyroid hormone disorder can actually lead to the other. Medications such as lithium can cause thyroid hormone disorders as well.
Often, an autoimmune disease is responsible for thyroid hormone disorders in the body. For instance, Grave's disease often causes hyperthyroidism. If someone has Grave's disease, her immune system attacks the thyroid, which encourages the gland to produce extra thyroxine. Grave's disease can be treated with anti-thyroid medications, which reduce the amount of hormones the gland produces.
Another common treatment for Grave's disease and hyperthyroidism in general is radioactive iodine treatment. The thyroid uses iodine to produce the hormones T-3 and thyroxine. When a person takes a dose of radioactive iodine, the overactive cells are destroyed by radioactivity. The gland shrinks as the cells are destroyed.
In many cases, a person will develop hypothyroidism as a result of treatment for hyperthyroidism. While the thyroid may begin to function normally after some time, in many cases, the person will need to take a synthetic thyroid hormone for the rest of her life in order to regulate the gland. This is particularly true if she underwent radioactive iodine treatment or had surgery to treat the thyroid hormone disorders.
Other common thyroid disorders include goiter and thyroiditis. Both conditions are usually caused by hyperthyroidism or hypothyroidism. A goiter occurs when the thyroid becomes enlarged. In some cases, a goiter will not affect the amount of hormones produced by the thyroid. A lack of iodine, auto immune diseases, or the presence of the human chorionic gonadotropin (HCG) hormone, which is produced during pregnancy, can lead to a goiter.
Thyroiditis is the inflammation of the thyroid gland that usually leads to hyperthyroidism, as the inflamed gland causes excess thyroxine to leak into the bloodstream. The condition can be caused by certain medications taken to treat cancer, by too much iodine, or by pregnancy. Typically, as a person recovers from thyroiditis, her thyroid will produce too many hormones, then too few, until finally returning to normal levels of thyroxine production.