Hyperthyroidism and thyrotoxicosis

The term thyrotoxicosis applies to a clinical condition resulting from increased thyroid hormone concentration and action. When the clinical condition is diagnosed by appropriate laboratory tests, the etiology should be determined. A high radioiodine uptake of thyroid will indicate either a very common condition called Graves' hyperthyroidism or a very uncommon TSH-secreting pituitary adenoma. A very low uptake or no uptake will indicate destructive thyroiditis, iodine-induced hyperthyroidism, or very rare cases of extra-thyroidal thyroid hormone production or exogenous thyroid hormone intake. Normal radioactive thyroid uptake can occur in mild Graves' hyperthyroidism or in multinodular toxic goiter and toxic adenoma. Management should be problem oriented and should depend on the etiology. Antithyroid medications, surgery, or radioactive iodine therapy can be used for high uptake causes and symptomatic therapy can be used for destructive thyroiditis. Iodine-induced hyperthyroidism will respond to antithyroid medications and elimination of exogenous iodine.