Subclinical thyroid disease can be a challenge to identify but can have adverse health effects.
Features showed by subclinical hyperthyroidism or hypothyroidism:
(1) clinically asymptomatic
(2) normal serum concentrations of free thyroxine and free triiodothyronine
The key feature is the serum TSH concentration:
(1) if elevated, then suspect subclinical hypothyroidism
(2) if decreased, then suspect subclinical hyperthyroidism
Subclinical hyperthyoidism may be associated with:
(1) atrial fibrillation or atrial flutter
(2) increased factor X activity
Subclinical hypothyroidism may be associated with:
(1) abnormal lipid metabolism
(2) elevated risk of atherosclerosis
(3) elevated risk of ischemic heart disease
(4) pericardial effusion
