The thyroid is a small, butterfly-shaped gland located in the neck and responsible for producing hormones that control metabolism in the body. Thyroidism is any disease or condition that offsets the body's normal hormonal balance. Common causes of thyroidism include hypothyroidism, hyperthyroidism and thyroid cancer.
Hypothyroidism
Hypothyroidism, or an underactive thyroid, causes the thyroid gland to under produce hormones required for the body to function normally. While this condition can affect anyone, MayoClinic.com reports that it is most commonly found in women over age 50. Symptoms associated with an underactive thyroid include fatigue, increased sensitivity to cold, unintended weight gain, brittle hair and nails and, muscle and joint aches. Hypothyroidism usually requires lifetime treatment with levothyroxine, a synthetic hormone that restores adequate hormone levels.
Hyperthyroidism
An overactive thyroid causes a condition called hyperthyroidism. This condition is characterized by an overproduction of thyroid hormone. According to MedlinePlus, diseases and conditions such as Graves' disease and thyroiditis, and getting too much iodine can cause hyperthyroidism. Symptoms associated with and overactive thyroid include weight loss, irritability, sleep disturbances and muscle weakness. Treatment for hyperthyroidism includes drug therapy, radioactive iodine treatment and surgery.
Thyroid Cancer
Thyroid cancer can also cause thyroidism. While the exact cause of thyroid cancer is not always known, onset is often related to exposure to radiation, family history, and age. The National Cancer Institute reports symptoms of thyroid cancer may include a lump in the front of the neck, a horse voice and swollen lymph nodes. Treatment for thyroid cancer depends on the stage of the cancer and can include hormone treatment, surgery, radiation and chemotherapy.
