Approach to a low TSH level: patience is a virtue.
Confronted with a low serum level of thyrotropin (thyroid-stimulating hormone, TSH), physicians should not jump to the conclusion that it is due to a hyperthyroid state, as other conditions and some drugs can be associated with a TSH level that is slightly low (0.1-0.4 microIU/mL) or frankly suppressed (< 0.1 microIU/mL). This review discusses how to approach a low TSH, stressing the frequent need to reassess thyroid function before making a diagnosis, the underlying processes and the drugs that can be responsible, and the degree of TSH suppression and its role in the evaluation.
Endocrinology and Metabolism Institute, F20, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA. pantalk@ccf.org
Kevin M
KM
Pantalone
Christian
C
Nasr
D000328:Adult; D006063:Chorionic Gonadotropin; D018450:Disease Progression; D005067:Euthyroid Sick Syndromes; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D007037:Hypothyroidism / Q000097:blood*; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D006063:Chorionic Gonadotropin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine