Subclinical hypothyroidism. Understanding is the key to decision making

Subclinical hypothyroidism is defined by elevated concentrations of thyrotropin (TSH) and normal levels of serum thyroxine in the absence of overt symptoms. Autoimmune thyroid disease is the most frequent cause. Prevalence is between 2.5% and 10%, depending on the patient population. The disorder may not be as asymptomatic as previously thought; mild but consistent hypothyroid symptoms may exist in 25% to 50% of patients. Subtle cardiac defects may be present and are probably most clinically relevant in patients with existing heart disease. Mild disturbances in cholesterol metabolism are a more common finding. Treatment of subclinical hypothyroidism must be individualized. The lowest dose of levothyroxine sodium (Levothroid, Levoxine, Synthroid) required to normalize TSH levels and improve symptoms yet avoid unnecessary side effects should be used.