Infective meningo-encephalitis in the immune competent adult in intensive care

Abstract

Encephalitis refers to an acute or subacute, inflammatory process affecting the brain in association with clinical evidence of neurologic manifestations such as altered consciousness, seizures or focal disturbances and cerebrospinal fluid abnormalities. This clinical syndrome is associated with a number of infectious, post-infectious, and non-infectious causes. An infection by a virus is the most common and important cause of encephalitis, although bacteria and parasites may sometimes be responsible for this syndrome. Three recent multicentre studies conducted in the USA, France and England, respectively, have shown that extensive testing may substantially reduce the proportion of unknown causes, which still varies from 37 to 70%.Magnetic resonance imaging is the most sensitive neuroimaging test to evaluate patients with encephalitis, while performing nucleic acid amplification by polymerase chain reaction (PCR) of CSF specimens may increase the ability to identify certain etiologic agents. Herpes simplex virus is the most frequent cause of sporadic necrotizing encephalitis and is the most frequently identified pathogen. Since Herpesviral encephalitis is associated with a substantial incidence of mortality and severe disability, early acyclovir therapy should be initiated in all patients with suspected encephalitis, pending results of neuroimaging and PCR testing. The number of emerging infectious diseases (EIDs) and the magnitude of their threat to global health is increasing. Viral EID’s may produce severe neurologic symptoms including encephalitis. In patients with encephalitis and a history of recent illness, the diagnosis of acute disseminated encephalomyelitis should be considered.