Subclinical Hyperthryoidism

Low TSH + Normal FT4 + Normal FT3 -> subclinical hyperthryoidism

studies lack, but hyperthyroidism treatment (antithyroid meds/radioactive iodine) probably helps against osteoporosis and cardiac arrhythmia.

Cause:

Exogenous - thyroid hormone tablet.

Endogenous -  multinodular goiter, thyroid adenoma - are the most common cause of endogenous subclinical hyperthyroidism.

Rx:

TSH < 0.1 mU/ml  -> treat the cause.

TSH 0.1~0.5

-> in elderly or high risk pt - treat the cause.

-> in low risk pt - observe. repeat blood test every 6 months.