Subclinical hyperthyroidism

Subclinical hyperthyroidism is defined as a situation where the levels of the peripheral thyroid hormones are normal but serum thyrotropin (TSH) is low. It is not a rare finding; rates between 0.2% and 11.8% have been reported in different groups, according to age, sex, etc. The etiology is usually the same as that of overt hyperthyroidism. The health implications include general symptoms, effects on the cardiovascular system, and decreased bone density. The increased frequency of atrial fibrillation and the increased mortality reported are especially serious. It is not clear whether subclinical hyperthyroidism should be treated or not. Most authors conclude that treatment is required in selected cases or in special circumstances.