Encephalitis

Pathological state of brain parenchymal dysfunction leading to an altered state of consciousness or focal neurological signs.

Serious, complex, and potentially fatal disorder with non-infectious and infectious causes.

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

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

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

Complications include seizures, hydrocephalus, and neurological sequelae (e.g., behavioural disturbances, motor problems).

Encephalitis is defined as inflammation of the brain parenchyma associated with neurological 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 non-infectious causes. Unfortunately, an aetiological 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