Hyperthyroidism describes the situation in which excessive quantities of thyroid hormone are produced. There are different causes for hyperthyroidism. Graves’ hyperthyroidism (1) is caused by immunoglobulins that stimulate the TSH receptors in thyroid follicular cells, and thereby increase the thyroid activity. Other causes for hyperthyroidism are (2) a continuously active TSH receptor in a toxic adenoma (TSH receptor mutation), (3) excessive amounts of TSH due to a TSH-producing adenoma (secondary hyperthyroidism) or (4) inflammation (thyroiditis), which results in leakage of thyroid hormone from the cell, and (5) multinodular goiter.
Symptoms can be goiter (enlarged thyroid gland), increased heart rate, nervousness, insomnia, mood shifts, restlessness, and fatigue. In Graves’ hyperthyroidism sometimes protrusion of the eyes is seen. Treatment of hyperthyroidism is focused on inhibition of thyroid hormone synthesis by thionamides.
I. Hyperthyroidism is always associated with goiter.
II. Primary hypothyroidism has familial predisposition.
Extra info: Goiter can accompany hyperthyroidism, but this is not always true