Inflammatory and infective causes of dementia

Inflammation occurs as part of the pathology of many dementias including most neurodegenerative disorders, amyloidosis and stroke. Only a small proportion of all cases of dementia are primarily due to inflammation or infection. These cases are important because they can be treated with a chance of improvement or stabilization of cognitive impairment. In general they present more rapidly than the primary degenerative dementias, with atypical features such as focal deficit, seizures or diminuition of consciousness. Abnormalities on magnetic brain imaging and CSF examination will usually point the clinician towards this group of conditions. This article provides an introduction to the clinical syndromes of infectious and inflammatory causes of dementia, including relevant investigations. Specific treatment of these rare disorders, however, is beyond the scope of this chapter.