Etiology
4 main types:
- Transient hyperthyroidism: Early stages of thyroiditis or levothyroxine excess
- Thyrotoxicosis: Excessive thyroid levels triggered by stressors
- Subclinical hyperthyroidism: Low TSH with normal T3/T4
- Overt hyperthyroidism: Low TSH & High T3/T4, Multiple causes including Graves’ disease
Common causes:
- Graves’ disease (MC): Autoimmune condition, peak 30-50’s and more common in women with TSH receptor antibodies. 1 in 3 develop orbitopathy
- Toxic multinodular goitre: usually in people >60 living in iodine-deficient areas (e.g., Denmark)
- Toxic thyroid nodules (follicular adenomas): More in older people
- High HCG conditions: Gestational thyrotoxicosis, hyperemesis gravidarum, Hydatiform mole
- Medication-induced: Amiodarone, lithium, levothyroxine excess, contrast agents
- Post-partum thyroiditis: Anti-TPO antibodies, occur 6 months post birth/miscarriage
- De Quervain’s Thyroiditis: secondary to viral infections, pain and fever are present
- Extra-thyroidal: Ovarian teratomas