Hyperthyroidism

Not to be confused with Hyperthyroxinemia or Hypothyroidism.

Hyperthyroidism is a medical condition. It is caused by a thyroid gland that is too active.

Hyperthyroidism
Other names	Overactive thyroid, hyperthyreosis
Triiodothyronine (T3, pictured) and thyroxine (T4) are both forms of thyroid hormone.
Medical specialty	Endocrinology
Symptoms	Irritability, muscle weakness, sleeping problems, fast heartbeat, heat intolerance, diarrhea, enlargement of the thyroid, weight loss[1]
Complications	Thyroid storm[2]
Usual onset	20–50 years old[2]
Causes	Graves' disease, multinodular goiter, toxic adenoma, inflammation of the thyroid, eating too much iodine, too much synthetic thyroid hormone[1][2]
Diagnostic method	Based on symptoms and confirmed by blood tests[1]
Treatment	Radioiodine therapy, medications, thyroid surgery[1]
Medication	Beta blockers, methimazole[1]
Frequency	1.2% (US)[3]
Deaths	Rare directly, unless thyroid storm occurs; associated with increased mortality if untreated (1.23 HR)[4]

The thyroid gland makes hormones. These hormones manage the body’s metabolism. An example of one of these hormones is thyroxine.

Synthesis

The thyroid hormones T₃ and T₄ have a number of metabolic, cardiovascular and developmental effects on the body. The production is stimulated by release of thyroid stimulating hormone (TSH), which in turn depends on release of thyrotropin releasing hormone (TRH). Every downstream hormone has negative feedback and decreases the level of the hormone that stimulates its release.

The thyroid-stimulating hormone starts the making of thyroxine. The thyroid-stimulating hormone is also called “TSH.”

TSH is made in the pituitary gland. Hyperthyroidism is determined by a doctor by blood tests that show a decreased thyroid-stimulating hormone (TSH) level.^[5]

Cause

The most common cause of this disorder is "Graves’ disease.” Graves’ disease is a condition in which the thyroid gland becomes overactive. Antibodies from the immune system in the bloodstream attack itself (this is called an autoimmune disease). This causes the thyroid gland to grow, as well as produce more thyroid hormones.^[6]

Symptoms

Some symptoms of this disorder are the swelling of the neck, as well as weight loss. In addition, patients could experience their hands trembling, as well as their blood pressure increasing. They could also experience nervousness and anxiety attacks.^[7] Medication can stop the effects of hyperthyroidism. However, hyperthyroidism cannot be fixed completely. Hyperthyroidism can occasionally cause death.^[8]