Encephalitis

Diagnostic definition[2]Venkatesan A, Tunkel AR, Bloch KC, et al. Case definitions, diagnostic algorithms, and priorities in encephalitis: consensus statement of the International Encephalitis Consortium. Clin Infect Dis. 2013 Oct;57(8):1114-28. https://academic.oup.com/cid/article/57/8/1114/529190/Case-Definitions-Diagnostic-Algorithms-and http://www.ncbi.nlm.nih.gov/pubmed/23861361?tool=bestpractice.com ​​

Diagnostic criteria for encephalitis and encephalopathy of presumed infectious or autoimmune etiology

• Major criterion (required):

  • Patients presenting to medical attention with altered mental status (defined as decreased or altered level of consciousness, lethargy, or personality change) lasting ≥24 hours with no alternative cause identified.

• Minor criteria (2 required for possible encephalitis; ≥3 required for probable or confirmed encephalitis):

  • Documented fever ≥100.4ºF (38ºC) within the 72 hours before or after presentation

  • Generalized or partial seizures not fully attributable to a preexisting seizure disorder

  • New onset of focal neurologic findings

  • Cerebrospinal fluid WBC count ≥5/mm³

  • Abnormality of brain parenchyma on neuroimaging suggestive of encephalitis that is either new from prior studies or appears acute in onset

  • Abnormality on electroencephalography that is consistent with encephalitis and not attributable to another cause.

Confirmed encephalitis requires one of the following:

• Pathologic confirmation of brain inflammation consistent with encephalitis

• Defined pathologic, microbiologic, or serologic evidence of acute infection with a microorganism strongly associated with encephalitis from an appropriate clinical specimen

• Laboratory evidence of an autoimmune condition strongly associated with encephalitis.