Fibromuscular dysplasia and childhood stroke

Arteriopathies are the leading cause of childhood stroke but mechanisms are poorly understood. Fibromuscular dysplasias are non-inflammatory arteriopathies classically described in adults with a cerebral-renal distribution and distinct 'string-of-beads' angiographic appearance. Diagnostic characteristics of paediatric fibromuscular dysplasia are uncharacterized. We aimed to compare pathologically proven versus clinically suspected paediatric fibromuscular dysplasia stroke cases to elucidate diagnostic features. Children in the Canadian Paediatric Ischaemic Stroke Registry, Calgary Paediatric Stroke Program, and published literature were screened for stroke associated with fibromuscular dysplasias or renal arteriopathy. Comparison variables included pathological classification, presentations, stroke types, imaging/angiography, treatments, and outcomes. We report 81 cases (15 new, 66 from the literature). For pathologically proven fibromuscular dysplasia (n = 27), intimal fibroplasia predominated (89%) and none had typical adult medial fibroplasia. Ischaemic strokes predominated (37% haemorrhagic) and were often multifocal (40%). Children often presented early (33% <12 months). Angiography demonstrated focal, stenotic arteriopathy (78%) rather than 'string-of-beads'. Renal arteriopathy (63%) with hypertension (92%) was common, with systemic arteriopathy in 72%, and moyamoya in 35%. Anti-inflammatory (29%) and anti-thrombotic (27%) therapies were inconsistently applied. Outcomes (mean 43 months) were poor in 63%, with stroke recurrence in 36%. Clinically suspected fibromuscular dysplasias (n = 31) were usually older, normotensive with string-of-beads angiography and good outcome. We conclude that fibromuscular dysplasia causes childhood stroke with distinctive clinic-radiological features including hypertension and systemic arteriopathy. Intimal fibroplasia predominates while 'string of beads' angiography is rare. Accurate clinical diagnosis is currently challenging.