[Various infective diseases of the nervous system]

A variety of viral, bacterial, fungal and spirochete infections may invade both the central and peripheral nervous system. The neurological hallmarks of these infectious diseases are very diverse and resulting in meningitis, meningoradiculitis, or as encephalomyelitis from the very start. Accordingly, patients may present with the cardinal signs of meningitis alone, or in association with focal neurological deficit, or with encephalopathy. This variability is related to the physiopathological mechanisms depending on the nature of the infectious agent. Thus the disease processes are due to the cytopathogenic action of these agents on the one hand and on the collateral damage induced by the immunological defence reaction of the patient on the other hand. In any case, serological and molecular analysis of blood and CSF samples are mandatory in order to diagnose correctly the underlying agent and to install prompt treatment that should be adapted to the new coming results. In this paper we will show examples of the clinical presentation of the most frequently encountered infectious diseases, the diagnostic approach and treatment.