Etiologies-hyperthyroidism
- Graves’ disease (60–80% of thyrotoxicosis)
- Thyroiditis: thyrotoxic phase of subacute (granulomatous) or painless (lymphocytic)
- Toxic adenomas (single or multinodular goiter)
- Extremely rare: TSH-secreting pituitary tumor or pituitary resistant to thyroid hormone (↑ TSH, ↑ free T4)
- Misc: amiodarone, iodine-induced, thyrotoxicosis factitia, struma ovarii (3% of ovarian dermoid tumors and teratomas), tumors (eg, choriocarcinoma) secreting hCG (weak bioactivity against TSH-R), large deposits of metastatic follicular thyroid cancer