Hyperthyroidism

Hyperthyroidism is a condition in which an overactive thyroid gland is producing an excessive amount of thyroid hormones that circulate in the blood. Thyrotoxicosis is a toxic condition that is caused by an excess of thyroid hormones. Thyrotoxicosis can be caused by an excessive intake of thyroid hormone or by overproduction of thyroid hormones by the thyroid gland.

Thyroid hormones stimulate the metabolism of cells. They are produced by the thyroid gland, located in the lower part of the neck. The gland wraps around the windpipe (trachea) and has a shape that is similar to a butterfly formed by two wings (lobes) and attached by a middle part (isthmus). The thyroid gland removes iodine from the blood and uses it to produce thyroid hormones.

Some common causes of hyperthyroidism include: Graves' Disease, functioning adenoma ("hot nodule") and toxic multinodular goiter (TMNG), excessive intake of thyroid hormones, abnormal secretion of TSH, thyroiditis (inflammation of the thyroid gland), excessive iodine intake

The triggers for Grave's disease include: stress, smoking, radiation to the neck, medications, and infectious organisms such as viruses.

Graves' disease can be diagnosed by a standard, nuclear medicine thyroid scan which shows diffusely increased uptake of a radioactively-labeled iodine. In addition, a blood test may reveal elevated TSI levels.

Common symptoms include: Excessive sweating, heat intolerance, increased bowel movements, tremor (usually fine shaking), nervousness; agitation, rapid heart rate, fatigue, decreased concentration


Treatments for hyperthyroidism include medications, ablation, and surgery. Surgery to partially remove the thyroid gland (partial thyroidectomy) was once a common form of treatment for hyperthyroidism. The goal is to remove the thyroid tissue that was producing the excessive thyroid hormone. However, if too much tissue is removed, an inadequate production of thyroid hormone may result. In this case, thyroid replacement therapy is begun. The major complication of surgery is disruption of the surrounding tissue, including the nerves supplying the vocal cords and the four tiny glands in the neck that regulate calcium levels in the body (the parathyroid glands). Accidental removal of these glands may result in low calcium levels and require calcium replacement therapy.

Frederic Gaspoz