Case Definitions, Diagnostic Algorithms, and Priorities in Encephalitis: Consensus Statement of the International Encephalitis Consortium

Encephalitis results in substantial morbidity and mortality worldwide. Specific etiologies are identified in <50% of cases, in part due to lack of consensus on case definitions and standardized diagnostic approaches. Advances in encephalitis are hampered by the rarity and heterogeneity of cases, highlighting the need for a collaborative international approach. In March 2012, the International Encephalitis Consortium held a meeting in Atlanta to discuss recent advances in encephalitis and to set priorities for future study. This consortium is an ad-hoc committee begun in 2010 with members from the Americas, Europe, Australia, Africa, and Asia. The mission of the consortium is to advance knowledge of the causes, diagnostic strategies, treatment, and outcome of encephalitis, and to implement interventions based upon this knowledge. Topics discussed at the meeting included: (1) standardization of a case definition for encephalitis, (2) development of practical diagnostic algorithms for evaluation of patients, (3) the role of host genetics in encephalitis, and (4) priorities for the study of selected emerging infectious diseases. Here we present a consensus document that synthesizes our discussions and recent literature, with the goals of aiding clinicians evaluating patients with suspected encephalitis and of identifying priorities and approaches to advance knowledge of encephalitis.