Moyamoya syndrome associated with Graves' disease: a case series study

The aim of this study was to describe the clinical and radiological findings of patients with moyamoya syndrome and Graves' disease. Possible mechanisms predisposing these individuals to ischemic stroke are discussed.

We retrospectively analyzed 12 consecutive patients with both moyamoya syndrome and Graves' disease. Moyamoya vasculopathy was diagnosed by digital subtract angiography or magnetic resonance angiography (MRA). The clinical characteristics, laboratory data, vascular radiological characteristics and outcome were reported.

All patients were female and mean age was 33.33±12.65 years. Stenosis or occlusion of bilateral terminal internal carotid artery and/or proximal anterior/middle cerebral arteries was found in nine patients. Among them, three patients displayed asymmetrical stenosis. In addition, there were three patients with probable unilateral moamoya syndrome. Eleven patients presented with ischemic stroke and/or transient ischemic attack (TIA) and one with dizziness. Thyroid function tests demonstrated elevated thyroid hormone levels and suppressed thyroid stimulating hormone levels in all the patients with ischemic events. All patients received anti-thyroid therapy and two had recurrent ischemic attack after drug withdrawal.

Moyamoya syndrome associated Graves' disease often presented with asymmetric stenosis or occlusion. We hypothesize cerebrovascular hemodynamic changes due to thyrotoxicosis contribute to the ischemic events.