Encephalitis

Pathologic state of brain parenchymal dysfunction leading to an altered state of consciousness or focal neurologic signs.

Serious, complex, and potentially fatal disorder with noninfectious and infectious causes.

Presents with acute onset of a febrile illness and altered mental status; typical features include headache, seizures, and focal neurologic signs.

Investigations should include blood cultures, neuroimaging (preferably MRI), and CSF analysis.

Acyclovir should be administered as soon as possible in all cases of suspected viral encephalitis.

Complications include seizures, hydrocephalus, and neurologic sequelae (e.g., behavioral disturbances, motor problems).

Encephalitis is defined as inflammation of the brain parenchyma associated with neurologic dysfunction[1]Tunkel AR, Glaser CA, Bloch KC, et al; Infectious Diseases Society of America. The management of encephalitis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2008 Aug 1;47(3):303-27. https://academic.oup.com/cid/article/47/3/303/313455/The-Management-of-Encephalitis-Clinical-Practice http://www.ncbi.nlm.nih.gov/pubmed/18582201?tool=bestpractice.com such as altered state of consciousness, seizures, personality changes, cranial nerve palsies, speech problems, and motor and sensory deficits. It is the result of direct inflammation of the brain tissue, as opposed to the inflammation of the meninges (meningitis), and can be the result of infectious or noninfectious causes. Unfortunately, an etiologic agent is only identified in around 50% of cases.[1]Tunkel AR, Glaser CA, Bloch KC, et al; Infectious Diseases Society of America. The management of encephalitis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2008 Aug 1;47(3):303-27. https://academic.oup.com/cid/article/47/3/303/313455/The-Management-of-Encephalitis-Clinical-Practice http://www.ncbi.nlm.nih.gov/pubmed/18582201?tool=bestpractice.com