Vasculitis and collagen vascular diseases

That part of the clinical interface between neurology and general medicine occupied by inflammatory and immunological diseases is neither small nor medically trivial. Neurologists readily accept the challenges of ‘primary’ immune diseases of the nervous system: these tend to be focussed on one particular target such as oligodendrocytes or the neuro-muscular junction present in predictable ways, and are amenable as a rule to rational, methodological diagnosis, and occasionally even treatment. This is proper neurology.‘Secondary’ neurological involvement in diseases mainly considered systemic inflammatory conditions—for example, SLE, sarcoidosis, vasculitis, and Behçet’s—is a rather different matter. It may be difficult enough to secure such a diagnosis even when systemic disease has previously been diagnosed and new neurological features need to be differentiated from iatrogenic disease, particularly drug side effects or the consequences of immune suppression. But all the diseases mentioned may present with and confine themselves wholly to the nervous system; they may mimic one another, and pursue erratic and unpredictable clinical courses. In central nervous system disease, diagnosis by tissue biopsy is potentially hazardous and unattractive. Few neurologists enjoy excesses of confidence or expertise when faced with such clinical problems: the cautious diagnostician is perplexed, and the evidence-based neuroprescriber confounded. Unsurprisingly, great variations in approaches to diagnosis and management are seen (Scolding et al. 2002b).But rheumatologically inclined general, renal or respiratory physicians, comfortable when managing inflammation affecting their system or indeed other parts of the body designed to support the nervous system, are generally also ill at ease when faced with neurological features whose differential diagnosis may be large, particularly given the near universal diagnostic non-specificity of either imaging or CSF analysis.Here then is the subject material for this chapter: the diagnosis and management of central nervous system involvement in inflammatory and immunological systemic diseases (Scolding 1999a). In not one of these neurological conditions has a single controlled therapeutic trial been reported, and much that is published on these conditions is misleading or inaccurate. And yet the frequency with which the diagnosis is only confirmed or even first emerges at autopsy bears stark witness to both the severity and evasiveness of these disorders.