Definition
- Autoimmune disease
- Caused by thyroid-stimulating hormone-receptor antibodies
- Stimulating growth of the thyroid and overproduction of thyroid hormone
Overview
- Most common cause of hyperthyroidism
- Women > Men, age 20-40
Aetiology
- TSH Receptor autoantibodies stimulate TSH-R
- ? Genetic cause (twin studies)
- Cross reactivity with the retro-orbital tissue
- Leads to mucopolysaccharides deposition in the extra ocular fat
- Inflammation and swelling of occular muscles
Symptoms
- Triad of symptoms
- Signs and symptoms of thyrotoxicosis
- Goitre (may have bruit related to increased vascular flow)
- Ophthalmopathy + Exophthalmos
- Ocular symptoms can be severe, including proptosis, periorbital oedema, lid retraction, tearing, blurry vision, eye pain, chemosis (conjunctival swelling), optic nerve damage, blindness, diplopia
- Retro-orbital tissue has over-expressed TSH-R
- Severe symptoms rarely seen now with screening assays
Treatment
- Beta-adrenergeric blocker
- There are three options to reduce thyroid hormone synthesis. These options are:
- Antithyroid drugs which block thyroid hormone synthesis and release
- Radioactive iodine (RAI) treatment of the thyroid gland
- Total or subtotal thyroidectomy
- Should be euthyroid
- If unable to be give Lugols iodine