Hyperthyroidism is only a clinical symptom. There are many causes that can lead to hyperthyroidism, and only when the causes are clearly identified can we target them. Etiology of hyperthyroidism: diffuse toxic thyroid disease, multinodular toxic goiter, autonomic high-functioning thyroid adenoma, follicular thyroid cancer, iodine-induced hyperthyroidism, pituitary TSH tumor or hyperplasia-induced hyperthyroidism, thyroiditis (subacute granulomatous thyroiditis, subacute lymphocytic thyroiditis, chronic lymphocytic thyroiditis, postpartum thyroiditis), exogenous thyroid hormone replacement, ectopic thyroid hormone production.