[Subclinical thyroid disorders].Pol Merkur Lekarski 2006; 21(126):573-8PM
The term subclinical thyroid disorders apply to patients who have an abnormal serum thyroid-stimulating hormone (TSH) concentration but thyroxine and triiodothyronine levels within their reference ranges. Subclinical hypothyroidism occurs in 4% to 10% of the general population, and is especially prevalent in elderly women. Depending on the study, subclinical hyperthyroidism has been found in 0.6-16 % of the population. Potential risks of subclinical hypothyroidism include progression to overt hypothyroidism, dyslipidemia, cardiovascular complications, and neurological and neuropsychiatric effects. In turn, subclinical hyperthyroidism represents a considerable risk factor for atrial fibrillation in the elderly and for postmenopausal osteoporosis. Treatment of subclinical thyroid disorders is controversial. In this paper, we discuss the prevalence, aetiology, clinical presentation, diagnosis, natural history, and potential pathophysiological consequences of subclinical hypothyroidism and subclinical hyperthyroidism. We also provide some screening and management recommendations.