[Treatment of hypothyroidism]

Hypothyroidism is a common disease with a prevalence of 5-6% in women and 1-2% in men. Primary hypothyroidism is the most common form (> 98%) autoimmune thyroiditis and thyroid destruction caused by radio-iodine treatment or thyroidectomy are the most common causes.

On the basis of relevant literature, an overview of diagnostic criteria and guidelines for treatment is presented.

An elevated TSH and a low free thyroxine level are diagnostic for primary hypothyroidism. The presence of anti-TPO antibodies indicates an autoimmune thyroiditis as the cause. In patients with non-thyroidal illness, a range of test abnormalities may be observed, making the interpretation of the test results difficult. Thyroxine is the preferred treatment of hypothyroidism. The therapeutic goal is to achieve a TSH level between 0.5-1.5 mIU/l. Most patients will then have thyroxine values in the upper 1/3 of the reference range, some will have elevated thyroxine values. If necessary, the thyroxine dose can be increased to give a TSH level between 0.2 and 1.0 mIU/l. In patients not satisfactorily treated with thyroxine alone, treatment with thyroxine combined with triiodothyronine may be tried. A diagnosis made on clinical grounds must always be verified biochemically before thyroxine treatment is started. The present literature does not support the treatment of patients complaining of "symptoms of hypothyroidism" such as tiredness, lethargy, weight gain and intolerance to cold, provided that their thyroid function tests are normal.