Table 1.
Pathogenic mechanisms and causes of thyrotoxicosis
| Cause | |
|---|---|
| Thyrotoxicosis with hyperthyroidism (normal or high radioactive iodine uptake) | |
|
| |
| Effect of increased thyroid stimulators | |
| TSH-receptor antibody | Graves’ disease |
| Inappropriate TSH secretion | TSH-secreting pituitary adenoma; pituitary resistance to thyroid hormone |
| Excess hCG secretion | Trophoblastic tumours (choriocarcinoma or hydatidiform mole); hyperemesis gravidarum |
| Autonomous thyroid function | |
| Activating mutations in TSH receptor or Gsα protein |
Solitary hyperfunctioning adenoma; multinodular goitre; familial non-autoimmune hyperthyroidism |
|
| |
| Thyrotoxicosis without hyperthyroidism (low radioactive iodine uptake) | |
|
| |
| Inflammation and release of stored hormone | |
| Autoimmune destruction of thyroid gland | Silent (painless) thyroiditis; post-partum thyroiditis |
| Viral infection* | Subacute (painful) thyroiditis (De Quervain thyroiditis) |
| Toxic drug effects | Drug-induced thyroiditis (amiodarone, lithium, interferon α) |
| Bacterial or fungal infection | Acute suppurative thyroiditis |
| Radiation | Radiation thyroiditis |
| Extrathyroidal source of hormone | |
| Excess intake of thyroid hormone | Excess exogenous thyroid hormone (iatrogenic or factitious) |
| Ectopic hyperthyroidism (thyroid hormone produced outside the thyroid gland) |
Struma ovarii; functional thyroid cancer metastases |
| Ingestion of contaminated food | Hamburger thyrotoxicosis1 |
| Exposure to excessive iodine | |
| Jod-Basedow effect | Iodine-induced hyperthyroidism (iodine, iodine-containing drugs, radiographic contrast agents) |
TSH=thyroid-stimulating hormone. hCG=human chorionic gonadotropin. Gsα=G protein alpha subunit.
*
Aetiology is not definitive.