Neurologic manifestations of systemic vasculitis

Vasculitis is defined as inflammation of blood vessels with associated structural damage and, usually, vascular necrosis. It may be caused by direct invasion of blood vessels and perivascular spaces by infectious organisms; by immunologic responses to drugs, heterologous proteins, or an underlying autoimmune, infectious, or neoplastic process (e.g., drug-induced vasculitis, vasculitis in the setting of systemic lupus erythematosus, polyarteritis nodosa [PAN] secondary to hepatitis B infection, or paraneoplastic vasculitis, respectively); or it may occur on an immunologic basis in the complete absence of any identifiable underlying disease (e.g., Wegener's granulomatosis [WG], temporal arteritis). The principal focus of this article will be on primary systemic vasculitides. The incidence of these vasculitides is estimated at 3.86/100,000/year.(80) This topic has recently been reviewed in detail.(60)