Update on investigation and management of postinfectious encephalitis

PURPOSE OF REVIEW: Encephalitis is a complex syndrome associated with significant morbidity and mortality. Despite biological and neuroimaging investigations, the cause of encephalitis remains undetermined in more than half of the cases. The aim of this review was to describe available data concerning diagnosis and treatment of postinfectious encephalitis, focusing on acute disseminated encephalomyelitis (ADEM) and acute hemorrhagic leukoencephalitis (AHLE). RECENT FINDINGS: The increasing availability of brain MRI studies has allowed a better delineation of diagnosis and prognosis of postinfectious central nervous system disorders. Beneficial effects of steroids and plasma exchange have been described in the most severe forms of postinfectious encephalitis, including ADEM and AHLE, but randomized controlled studies are lacking. Intravenous immunoglobulins may be of value in ADEM with peripheral nerve involvement and for patients in whom corticosteroid therapy is contraindicated. SUMMARY: Postinfectious encephalitis needs to be identified early in the management of patients with unexplained encephalitis as it represents a treatable disease. Randomized studies are needed in order to assess the potential benefit of early combined immunotherapy in ADEM.