When there are increased levels of thyroid hormone in the blood the patient is said to have thyrotoxicosis. Thyrotoxicosis affects 2% of the United Kingdom population. It is ten times more common in females than males and in 40% of patients the disease is self-limiting.
There are four main causes of thyrotoxicosis:
1) A generalised enlargement of the thyroid (Graves' Disease)2) An overactive solitary lump in the thyroid (Plummer's disease)3) Overactivity in a multinodular goitre (Toxic multinodular goitre)4) Inflammation of the thyroid resulting in release of excess thyroid hormone (Thyroiditis).
Other less common causes of thyrotoxicosis are: