What is Thyrotoxicosis?

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.

What are the causes of Thyrotoxicosis?

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:

  • Patients taking excess thyroid hormone (Thyrotoxicosis Factitia)
  • The passage from the mother to the foetus of maternal immunoglobulins that stimulate the foetal thyroid (Congenital Thyrotoxicosis)
  • Transient thyrotoxicosis occurs in 20% of women who have had previous thyrotoxicosis and normal thyroid function during pregnancy (Post-partum Thyroiditis)
  • Thyroid 'storm' is rarely seen, but is brought about by physical or surgical stress causing a massive release of thyroid hormone into the circulation (Thyrotoxic Crisis)
  • A non thyroidal tumour (eg ovary) that produces excessive amounts of TSH causing stimulation of the thyroid (Ectopic Hyperthyroidism)