[The stenoses at the terminal portion of the internal carotid artery improved after initiation of antithyroid therapy: a case report].

We reported the case of a 19-year-old female complicated with Basedow disease. She was admitted, complaining of headache and endocrine function tests showed hyperthyroidism. CT scan revealed left intraventricle hemorrhage and angiography revealed the stenoses at the terminal portion of the bilateral internal carotid arteries (ICA) without basal moyamoya vessels. During the angiography, a thyroid crisis occurred and we initiated the antithyroid therapy. Bilateral CAG a month after the onset revealed that the stenoses had improved partially and the stenosis was thought to be vasospasm caused by the intraventricle hemorrhage. But as the collateral circulation had already been established soon after the hemorrhage, we suspected that the stenoses at the terminal portion of the ICA had existed before the intraventricle hemorrhage. Angiography was performed one year after the onset and bilateral CAG revealed that the stenoses at the terminal portion of the ICA had also improved. As some investigators have mentioned that Basedow disease might be associated with the causal genesis of Moyamoya disease, we suspected that Basedow disease might have played an important role in vasospasm after hemorrhage and that the stenoses at the terminal portion of the ICA might have existed before the hemorrhage took place.