Demyelination due to systemic vasculitis
Definition
Globally, cerebrospinal involvement is infrequent in small-medium size vessel vasculitis, including Wegener’s granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome, polyarteritis nodosa, cryoglobulinemic vasculitis, and Behçet’s disease. CNS involvement occurs in less than 15% of patients. Transient ischaemic episodes or strokes can occur in a multifocal pattern in patients with a systemic vasculitis.Neurological involvement in polyarteritis nodosa, Churg-Strauss syndrome and Wegener's granulomatosis involves the peripheral nervous system with a rapidly involving and progressive mononeuritis multiplex or symmetrical polyneuopathy. Oculomotor palsies or visual impairment are seen with the orbital involvement that can occur in Wegener's granulomatosis [McAlpine, 2006, pg 404]. Patients with active polyarteritis will be systemically unwell and will have a raised erythrocyte sedimentations rate and the presence of anti-neutrophil cytoplasmic antobodies. This clinical picture, in addition to peripheral nerve and systemic non-neurologcial involvement, means that multiple sclerosis will rarely arise in the differential diagnosis of systemin vasulitis.