Indications for treatment of endogenous subclinical hyperthyroidism in nonpregnant adults*

TSH: thyroid-stimulating hormone.
* Subclinical hyperthyroidism is defined as a normal serum free thyroxine (T4) and triiodothyronine (T3) in the presence of a subnormal TSH, confirmed on repeated measurement over a three- to six-month period.
¶ Symptoms of hyperthyroidism include palpitations, tremulousness, heat intolerance, and insomnia (refer to UpToDate topics on hyperthyroidism).
Δ A radionuclide scan showing one or more focal areas of increased uptake is consistent with autonomy and is a risk factor for progression to overt hyperthyroidism.
◊ There are insufficient data for or against treatment of subclinical hyperthyroidism in patients with TSH between 0.1 and the lower limit of normal and in younger patients (<65 years of age) with TSH <0.1 mU/L. A decision for individual management is based upon patient characteristics and preferences (refer to UpToDate topics on subclinical hyperthyroidism).
§ Check TSH, free T4, and T3 every six months.