In general, patients suspected to have central hypothyroidism should be referred for consultation with an endocrinologist. Conversely, an increased TSH is not always caused by hypothyroidism, but rather it may occur in patients recovering from nonthyroidal illnesses, in those with impaired renal function, and in those with glucocorticoid deficiency. These symptoms are typically nonspecific and include fatigue, memory impairment, depression, cold intolerance, dry skin, constipation, and weight gain. In patients with mild hypothyroidism, impaired myocardial contractility can represent another reason for therapy. These associations were slightly stronger among women who had a positive antithyroid antibody test indicating thyroid autoimmunity.
Age is important in determining appropriate dosing.
Pregnant women receiving thyroid hormone replacement therapy may temporarily require higher doses of thyroxine because it is cleared more rapidly in them. Furthermore, compounds such as sucralfate, aluminum hydroxide gel, calcium carbonate, ferrous sulfate, and cholestyramine can interfere with thyroxine absorption. Follow-up should include clinical evaluation and TSH measurement approximately four weeks after the initiation of treatment and after any subsequent change in the thyroxine dose to ensure that an adequate TSH level is achieved but not exceeded. Once an appropriate thyroxine dose is established, annual clinical assessment and serum TSH measurement are sufficient. Once started for treatment of mild hypothyroidism, thyroxine therapy typically continues throughout a person's lifetime.