Definition

Hyperthyroidism is a condition in which the thyroid gland produces excessive amounts of thyroid hormones (T3 and T4), leading to an overactive metabolism.

Causes

The most common cause is Graves’ disease, an autoimmune disorder that overstimulates the thyroid to produce more hormones than normal. In rare cases, a single thyroid nodule may function as a hormone-secreting tumor, causing excessive hormone production.

Symptoms

Rapid heartbeat (palpitations), weight loss, hand tremors, anxiety, fatigue, increased appetite, heat intolerance, and excessive sweating. In Graves’ disease, untreated cases may develop thyroid eye disease, which can cause bulging eyes and vision loss.

Diagnosis

Blood tests show elevated levels of T3 and T4 with suppressed TSH. Thyroid autoantibodies are often elevated. Thyroid ultrasound and radioactive iodine uptake tests may be used to identify the cause and guide treatment.

Treatment

Treatment typically begins with antithyroid medications. If medication is ineffective, rapid normalization of thyroid function is needed, or thyroid eye disease is present, surgical removal of the thyroid gland may be recommended.