Hyperthyroidism is a disorder of the thyroid gland characterised by excessive production of thyroid hormones. The main cause of hyperthyroidism is Graves' disease, but it is not the only cause.
Other possible reasons that can trigger the production of high levels of thyroid hormones are:
- Diet with excess iodine.
- Thyroid inflammation or thyroiditis.
- Nodules in the thyroid.
- Benign tumours in the pituitary gland.