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Subclinical hyperthyroidism in nonpregnant adults

Douglas S Ross, MD
Section Editor
David S Cooper, MD
Deputy Editor
Jean E Mulder, MD


Subclinical hyperthyroidism is defined biochemically as normal serum free thyroxine (T4) and triiodothyronine (T3) concentrations in the presence of a subnormal thyroid-stimulating hormone (TSH) (<0.5 mU/L). The term overt hyperthyroidism refers to patients with elevated levels of free T4, T3, or both and a subnormal TSH concentration. Both subclinical and overt hyperthyroidism are biochemical definitions since hyperthyroid symptoms are nonspecific and may be present in patients with subclinical disease and absent in those with overt disease, especially older adults.

Subclinical hyperthyroidism in nonpregnant adults will be discussed here. Overt hyperthyroidism and hyperthyroidism during pregnancy are discussed separately.

(See "Overview of the clinical manifestations of hyperthyroidism in adults".)

(See "Diagnosis of hyperthyroidism".)

(See "Graves' hyperthyroidism in nonpregnant adults: Overview of treatment".)

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Literature review current through: Sep 2017. | This topic last updated: Oct 06, 2017.
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