Having an elevated thyroid level is a condition known as hyperthyroidism, meaning the thyroid gland is producing too much of the thyroid hormone thyroxine, according to WebMD. Hyperthyroidism has various causes, such as Graves' disease, toxic multinodular goiter, excessive intake of thyroid hormones and the abnormal secretion of thyroid-stimulating hormone.
The thyroid gland regulates metabolism, which effects the heart, cholesterol, muscles and bones. When the thyroid gland produces too much hormone, it increases metabolism, leading to weight loss, increased heart rate, excessive sweating, anxiousness or moodiness. Without treatment, hyperthyroidism can lead to serious heart and bone problems, reports WebMD.
The most common cause of hyperthyroidism is Graves' disease, a condition where the immune system attacks the thyroid gland, causing it to produce excessive thyroid hormones, states WebMD. An elevated thyroid level also can be caused by a swollen thyroid gland or small growths in the gland called thyroid nodules.
Hyperthyroidism does not go away on its own and requires treatment from a physician. In some cases, it causes a condition called thyroid storm if left untreated, a condition in which the thyroid releases a very large amount of hormone in a very short period of time, explains WebMD. A physician should be consulted immediately for any of signs of hyperthyroidism.