Recurrent Stroke in Two Children with Basilar Artery Occlusion and the Effects of Immunomodulatory Therapy

Only 10 to 30% of pediatric arterial ischemic strokes occur in the posterior circulation. The etiology of basilar artery occlusion (BAO) is often unknown. We report the clinical course of two unrelated 9-year-old boys (P1 and P2) with recurrent stroke due to BAO despite intensive antithrombotic treatment. P1 presented with headache, vertigo, ataxia, and aphasia. Brain magnetic resonance imaging (MRI) revealed a thrombosis in the distal basilar artery and bilateral infarctions in the cerebellum. He was anticoagulated with unfractionated heparin (UFH). P1 recovered gradually and had a first recurrence 9 days after the initial stroke, despite antiplatelet prophylactic treatment with acetylic acid (ASA) and a second relapse 4 weeks later, despite prophylactic anticoagulation with low-molecular-weight heparin. During the second relapse, MRI revealed an almost total BAO. P1 underwent immediate local thrombolysis with recombinant tissue plasminogen activator and mechanical thrombectomy with temporary stenting. P2 presented with acute right hemiparesis, aphasia, paresis of the hypoglossal nerve, and progressive somnolence. Brain MRI revealed irregular vessel walls with suspicion of a thrombus in the basilaris artery and the right posterior cerebral artery, leading to brain stem and cerebellar infarctions. He had two relapses within 15 days while on full antithrombotic treatment with ASA and UFH. In both the cases, extensive diagnostic work-up did not reveal the etiology. Both the patients underwent anticoagulation with UFH at therapeutical dose, followed by dual antiplatelet therapy (ASA and clopidogrel) after their second stroke recurrence. Assuming a cerebral vasculitis, both boys received 5 days of methylprednisolone pulse therapy after their second relapse and continuous immunomodulatory therapy with mycophenolate mofetil (MMF) thereafter. P1 and P2 remained symptom- and relapse-free for 17 and 5 months, respectively. P1 has mildly reduced fine motor skills, and P2 has a mild right hemiparesis. BAO is rare in childhood, with recurrence prevalence of 4 to 13% and poor outcome in 50%. Imaging characteristics of the basilar artery, relapses despite antithrombotic treatment alone, and response to immunomodulatory therapy point to childhood primary cerebral angiitis of the central nervous system in the two patients. Treatment with methylprednisolone and MMF in addition to dual antiplatelet therapy has thus far prevented further relapses and was associated with a satisfactory neurological outcome.