Seizure and Stroke in a Patient with Down Syndrome Diagnosed with Moyamoya Syndrome: A Case Report

Abstract

Moyamoya syndrome (MMS) is a rare, progressive occlusive vasculopathy characterized by stenosis of the distal internal carotid arteries and the formation of collateral vessels resembling a “puff of smoke” on angiography. Patients with Down syndrome (DS) have a significantly higher risk of MMS; however, diagnosis is often delayed due to underlying intellectual disability. We report the case of a 21-year-old male with Down syndrome who presented with recurrent ischemic strokes. Initial magnetic resonance imaging (MRI) revealed scattered infarcts in both hemispheres. Magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) demonstrated bilateral terminal internal carotid artery stenosis with compensatory anastomoses from the external carotid arteries, confirming the diagnosis of moyamoya syndrome. Due to adequate collateral circulation, the patient was managed conservatively with dual antiplatelet therapy rather than surgical revascularization. Unfortunately, the clinical course was complicated by Stevens–Johnson syndrome following antiseizure medication and subsequently severe pneumonia with bilateral pleural effusion, which ultimately led to the patient’s death. While confirming previous findings on the diagnostic challenges of MMS in DS, this report emphasizes that systemic complications pose a serious threat to these patients.