Graves Disease (Thyrotoxicosis)

Related Subjects: |Thyrotoxicosis and Hyperthyroidism |Thyroid Storm - Thyrotoxic crisis |Graves Disease (Thyrotoxicosis) |Amiodarone and Thyroid disease |Thyroid Surgery (Thyroidectomy) |Hypothyroidism |Hashimoto's thyroiditis |DeQuervain's thyroiditis |Subacute Thyroiditis |Thyroid nodule |Congenital Hypothyroidism |Thyroid Function Tests and antibodies |Post partum thyroiditis |Sick Euthyroid Syndrome |Thyroid Exam (OSCE) |Thyroid Gland anatomy and Physiology |Thyroid Cancer

Smokers with Graves' Disease are at increased risk of thyroid eye disease and must stop smoking.

About

• Autoimmune disease
• Commonest cause of hyperthyroidism (60-80%)

Risks

• Women > Men x 10 usually Age 30-50
• Increased presentation post partum
• Smoking major risk factor for eye disease
• Commonest cause of thyrotoxicosis

Aetiology

• Increased frequency of HLA B8 and DR3
• Thyroid stimulating Immunoglobulin (TSI) causing follicular hyperplasia
• TSI can cross the placenta
• Also has TPO antibodies in 80%
• In eye disease there is fibroblast activation and production of glycosaminoglycans
• Autoimmune with antibodies to TSH receptor in 80-90%

Clinical

• Weight loss, anxiety, tachycardia, heat intolerance, palpitations
• Thyrotoxicosis or Apathetic thyrotoxicosis in elderly
• Diffusely enlarged thyroid with thrill or bruit

Grave's disease specifically

• Thyroid acropachy and onycholysis - a form of clubbing unique to Grave's
• Pretibial myxoedema pink purple orange skin appearance of shins 5%
• Thyroid acropachy - resembles clubbing with distal swelling of fingers
• Eye disease 40%: Lid retraction, Lid lag, Proptosis, Diplopia as extraocular muscles involved, Corneal damage

Investigations

• High T4/T3 low TSH < 0.05 mIU/L
• TSH receptor antibodies more specific than to thyroid peroxidase
• Radionuclide scan - diffuse increased activity in goitre

Differential

• Nodular goitre
• Toxic adenoma
• Iatrogenic / Facetious - taking excess Thyroxine

Management

• Beta blockade: Propranolol
• Antithyroid drugs: Propylthiouracil or carbimazole 20-40 mg daily
• Radioactive Iodine
• Surgery (subtotal thyroidectomy)
• Anticoagulate if in AF

Eye disease

• The inferior rectus is involved first and the enlarged muscle tethers the eye and restricts upgaze. Compensatory increased innervation to the superior rectus and the levator palpebrae superioris. Leads to eyelid retraction.
• In thyrotoxicosis, increased sympathetic activity leads to bilateral eyelid retraction which resolves with beta-blockade and treatment of thyrotoxicosis.
• Smoking cessation. Can be worsened by radioiodine treatment
• Keep a close watch of acuity and expert ophthalmology care
• Gritty eyes: Eye drops 5% guanethidine and patch, Tarsorrhaphy
• Diplopia, Proptosis, altered visual acuity
• Immunosuppression: Steroids - Prednisolone 60 mg od, Ciclosporin, PLEX, Rituximab
• Others: Orbital irradiation, Orbital decompression