Recent in vitro and in vivo data indicate that intrathyroidal
iodine deficiency is the most important factor for the development of endemic goitre. Normalisation of the thyroid
iodine content is essential to achieve regression of
hyperplasia of
iodine-depleted thyroid tissue. As clinical studies clearly demonstrate
iodine should always be part of
therapy of euthyroid diffuse endemic goitre. After
therapy with
levothyroxine alone the intrathyroidal
iodine deficiency remains unchanged, and relapse of goitre will soon occur. There are the following indications for
conservative therapy of euthyroid diffuse endemic goitre: 1. Children and adolescents should be treated by
iodine alone (100-200 micrograms/die). 2. For adults a combined
therapy with
levothyroxine (100 micrograms/die) plus
iodine (200 micrograms/die) is to be preferred to avoid the possible induction of
thyrotoxicosis or autoimmune
thyroid disease by high
iodine doses (monotherapy with
iodine would need 400-500 micrograms/die). In addition no reduction of goitre volume can be expected in adults older than 40 years because of an increasing number of thyroid nodular formations. 3. During pregnancy the combination
therapy has advantages as high
iodine dosages of
iodine, potentially dangerous for the foetus, can be avoided whereas goitre formation in the mother is effectively suppressed and
iodine deficiency in mother and child is compensated. Goitre
therapy should be carried out at least for 6 months. The efficacy of goitre
therapy should be controlled by sonographic determination of thyroid volume at least once a year after the end of treatment. An effective goitre prophylaxis with 100-200 micrograms
iodine per day is recommended following the actual
therapy period.