About Hyperthyroidism

Overview

Hyperthyroidism is a clinical syndrome in which thyroid hormone produced in excess by the thyroid gland increases in the bloodstream, causing the thyroid's physiological actions to become excessive.

Definition

The thyroid, which secretes thyroid hormone, is located at the front of the neck and has a butterfly shape. Thyroid hormone is involved in the body's energy metabolism, helping maintain body temperature and regulate metabolism. When the thyroid produces excess thyroid hormone and the body generates more energy than needed, the body becomes hot, sweats a lot, loses weight, and autonomic nervous system activity becomes stimulated, causing the heart rate to increase. Conversely, if too little thyroid hormone is produced or thyroid function is abnormally reduced, the pulse slows, people become sensitive to cold, gain weight, and the heart rate also slows.

Hyperthyroidism is a clinical syndrome in which thyroid hormone produced in excess by the thyroid gland increases in the bloodstream, causing the thyroid's physiological actions to become excessive. Even when thyrotoxicosis occurs, actual hyperthyroidism does not.

The most important and common cause of hyperthyroidism is Graves' disease, an autoimmune disease. Other causes include primary hyperthyroidism due to toxic multinodular goiter, toxic goiter, metastatic functioning thyroid cancer, and struma ovarii, as well as secondary hyperthyroidism due to excessive secretion of thyroid-stimulating hormone from pituitary adenomas or hCG-secreting tumors. In addition, causes of thyrotoxicosis without hyperthyroidism include thyroiditis, temporary release of stored thyroid hormone, thyroid destruction, and factitious thyrotoxicosis caused by administration of thyroid hormone from outside the body.

Although it varies by region, Graves' disease accounts for about 60-80% of hyperthyroidism. It is rare before childhood onset and most commonly occurs between the ages of 20 and 50. It is more common in women than in men; the prevalence has been reported to be up to 2% in women, and in men it occurs at about one-tenth the frequency of women. Because it occurs more often in areas with high iodine intake, it is also common in Korea.

So far, I have explained hyperthyroidism. In the next part, we will look at the causes of hyperthyroidism.

Source: Korea Centers for Disease Control and Prevention, National Health Information Portal