Last reviewed 06/2021
Subclinical hyperthyroidism is a disorder in which TSH levels are suppressed in the presence of normal concentrations of free thyroid hormones.
The degree of TSH suppression required for the diagnosis is controversial but a level less than 0.1 mU/L is widely accepted.
- subclinical hyperthyroidism may be responsible for an increased cardiovascular risk, especially in presence of undetectable serum TSH (1)
- elderly patients with subclinical hyperthyroidism have an increased risk of atrial fibrillation, particularly in presence of an underlying heart disease (1)
- elderly patients with exogenous and endogenous subclinical hyperthyroidism have an increased risk of bone fracture (1)
differential diagnosis of low TSH concentration