Neurology of the vasculitides and connective tissue diseases

Neurological and psychiatric abnormalities are frequent complications of systemic autoimmune and inflammatory diseases. The range and acuity of these abnormalities vary widely, as do the immunopathogenic mechanisms. Progress in the understanding of likely mechanisms and potential therapies in these groups of disorders has come from diverse areas of investigation. Studies during the past decade detail the intrinsic role of the vasculature in the physiology of inflammation. Numerous small soluble molecules mediate autocrine and paracrine eVects within and between cells of the vasculature, tissue parenchyma, and haematopoietic system. Further, various pathological processes use the same mediators to actively target or passively injure blood vessels. These processes, which may result in acute or chronic vascular injury, are clearly evident in many of the systemic autoimmune diseases. In addition, systemwide responses to inflammatory stress or local injury evoke cascades and feedback loops of hormones and neurotransmitters. Although these responses are adaptive to the acute situation, they may contribute to the chronic injury when persistently activated. In another area, autoantibodies, prominent in many autoimmune diseases, are potential causes of cellular dysfunction. Distinguishing among the protective, pathogenic, and neutral role of autoantibodies, however, requires careful study.