Causes of thyrotoxicosis
| Thyrotoxicosis associated with hyperthyroidism | |
| Aetiologies (common) | Mechanism |
| Graves’ disease | Thyrotropin receptor antibodies stimulate the thyroid-stimulating hormone (TSH) receptor |
| Toxic multinodular goitre | Activating mutations in TSH receptor or G proteins |
| Solitary toxic adenoma | Functional autonomy within a benign lesion |
| Aetiologies (uncommon) | Mechanism |
| TSH secreting pituitary adenoma | Pituitary adenoma |
| Pituitary resistance to thyroid hormone | Mutation of thyroid hormone receptor β |
| Neonatal Graves’ disease | Thyroid stimulating immunoglobulins |
| Choriocarcinoma | Human chorionic gonadotropin |
| Hyperemesis gravidarum | Human chorionic gonadotropin |
| Congenital hyperthyroidism | Activating mutations in TSH receptor |
| Struma ovarii | Toxic adenoma within dermoid tumour of the ovary |
| Metastatic follicular thyroid carcinoma | Foci of functional autonomy |
| Iodine or iodine containing drugs | Jod-Basedow phenomenon; excess iodine results in unregulated thyroid hormone production |
| Thyrotoxicosis not associated with hyperthyroidism | |
| Aetiologies (common) | Mechanism |
| Thyroiditis Painless including postpartum | Autoimmune, release of stored thyroid hormones |
| Sub-acute thyroiditis | Viral infection, release of stored thyroid hormones |
| Exogenous thyroid hormone | Iatrogenic or factitious excess ingestion of thyroid hormone |
| Aetiologies (uncommon) | Mechanism |
| Drug induced thyroiditis | Destruction of thyroid follicles |
| Acute infectious thyroiditis | Bacterial or fungal thyroid infection |
| Radiation induced thyroiditis | Radioactive iodine induced thyrocyte destruction |
| Thyroid adenoma infarction | Release of stored hormones |