Overactive thyroid (hyperthyroidism)
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Cause
The most common cause of hyperthyroidism is Graves’ disease, an autoimmune condition in which the immune system attacks the thyroid gland, stimulating it to produce excessive amounts of thyroid hormone.
Other possible causes include autonomous thyroid nodules (which produce hormones independently), an enlarged thyroid gland (toxic goitre), thyroid inflammation (thyroiditis), or the use of certain medications.
The condition is more common in women than in men and can occur at any age, although it most often affects people between the ages of 20 and 40.
Symptoms
The symptoms below may occur.
- Rapid heartbeat and high blood pressure
- Unexplained weight loss
- Excessive heat sensation and sweating
- Diarrhea
- Trembling
Diagnosis
To make a diagnosis, a blood test is required to measure thyroid hormone levels and check for thyroid antibodies.
An ultrasound scan of the thyroid gland is usually performed, along with a thyroid scintigraphy (thyroid scan).
Treatment
Treatment of hyperthyroidism depends on the underlying cause and the severity of the condition.
Medication may be prescribed to reduce the production of thyroid hormones. Radioactive iodine therapy can be used to destroy part of the thyroid tissue, thereby lowering hormone levels. In some cases, surgery to remove part or all of the thyroid gland may be necessary.
To relieve symptoms such as a rapid heartbeat or tremors, beta-blockers may be temporarily prescribed.