The spectrum of CNS vasculitis in children and adults.

Children and adults who present with severe, newly acquired neurological or psychiatric deficits should be evaluated for an underlying inflammatory brain disease-the inflammation could be reversible, if diagnosed and treated rapidly. In our experience, primary angiitis of the central nervous system (PACNS) is the most common inflammatory brain disease and is increasingly recognized across patients of all ages. Distinct disease subtypes have been reported with characteristic disease courses, neuroimaging features and histopathological findings. In this Review, we provide a comprehensive comparison of childhood and adult PACNS, revealing distinct gender distributions, characteristic presenting clinical phenotypes and tailored differential diagnosis evaluations in the different subtypes of PACNS. Novel and traditional laboratory markers can help to define disease subtype and activity, whilst MRI and angiography can aid diagnosis in both children and adults. Characteristic patterns of parenchymal lesions and vessel involvement have been identified in PACNS and differ markedly between subtypes. Brain histopathology has also revealed distinct inflammatory pathways at different ages. Immunosuppressive treatment protocols have been shown to be effective and safe across the age spectrum; overall, in the past few years, the mortality of PACNS has decreased dramatically.