No abstract

Objective: To determine the effects of medical treatment on the thyroid gland, peripheral circulation, and laboratory findings in patients with Graves' disease. Methods: Twenty patients with Graves' disease were treated with either carbimazole and propranolol (group I) or carbimazole only (group II). Serum free thyroxine (FT 4), thyroid-stimulating hormone (TSH), and thyrotropin-binding inhibitory immunoglobulins (TBII) were estimated before and after 6 weeks of treatment. Duplex Doppler ultrasonographic examination of the thyroid, inferior thyroid artery (ITA), and common carotid artery (CCA) was performed before and after 2, 4, and 6 weeks of therapy. Results: Serum FT 4 and TBII decreased after treatment in both groups, whereas serum TSH increased in group I only. The volume of the thyroid gland and parenchymal blood velocity were increased in these patients and diminished only with addition of propranolol to carbimazole. A diffuse hypoechogenic pattern in the thyroid gland and increased ITA blood flow and peak velocity were observed in all patients and persisted throughout treatment. The mean CCA peak blood velocity was accelerated in Graves' disease and diminished after 6 weeks of therapy in both groups, whereas increased CCA blood flow diminished only in group I. Conclusion: A 6-week period of therapy with carbimazole and propranolol has no effect on the diffuse low echogenic pattern in the thyroid gland and the accelerated ITA blood flow in Graves' disease. The addition of propranolol is associated with early decrements in thyroid volume, parenchymal vascularity, and CCA blood flow as well as early recovery of TSH suppression, but it has no additional effect on thyroid hormone secretion or TBII levels.