A medical overview of encephalitis

Abstract

Encephalitis is uncommon but is a neurological emergency which must be considered in a patient presenting with altered consciousness. Encephalitis is a diffuse inflammatory process of the brain parenchyma associated with evidence of brain dysfunction. The presentation of encephalitis can be acute or chronic. The aetiology of encephalitis can be broadly divided into two major subtypes. (1) Infection-related encephalitis which is a direct consequence of pathogenic viral, bacterial or parasitic agents. Herpes simplex virus (HSV) and varicella-zoster virus (VZV) are the most common cause of acute infectious encephalitis. (2) Autoimmune-mediated encephalitis which is mediated by an aberrant immune response. This can be triggered by a recent viral infection or vaccination. An example of this would be acute disseminated encephalitis (ADEM). This article will focus on the medical management of acute encephalitis. This will involve an extensive overview of the literature reviewing the diagnosis, investigation and treatment of acute viral encephalitis, ADEM and acute haemorrhagic leukoencephalopathy (AHLE). Encephalitis can also present chronically, and some of the different types of chronic encephalitis will be discussed.

The Neuropsychiatric Consequences of Childhood Encephalitis: A Review of Cases from Middle-Eastern Countries

“…Focal motor signs may include cranial nerve palsies (especially the occulomotor nerve) and upper motor neuron pareses in limbs. Approximately 70 % of cases may result in severe neurological damage or death (Lishman, 2003;Stone and Hawkins, 2007). The sequels are directly related to the length of coma in the acute stage and inversely related to the age at infection.…”

“…Adult patients frequently report multiple, vague, somatic complaints. Depression, irritability, insomnia, forgetfulness, reduced concentration, and tremors may also be reported (Lishman, 2003;Stone and Hawkins, 2007). Recent studies conducted in Turkey and Middle-Eastern countries revealed that, Tick-borne and other arthropod related encephalitis may be commoner than thought before (Ergunay et al, 2007).…”

Clinical and economic importance of applying the guidelines for the diagnosis of viral encephalitis

“…L'encefalite colpisce l'encefalo in maniera diffusa; quando coinvolge le meningi si ha il quadro di meningo-encefalite, quando coinvolge il midollo si parla di encefalo-mielite. L'encefalite può essere primitiva o costituire la complicanza secondaria di un'infezione virale (14). Si suddividono, inoltre, le encefaliti in virali acute, se si manifestano entro breve tempo dall'infezione, e in encefaliti da virus lenti, se si manifestano dopo mesi o anni dall'infezione e hanno sviluppo progressivo.…”

“…Human Herpes Virus 6 (HHV6).L'herpes virus umano 6 è un agente a elevato neuro-tropismo, pertanto il suo isolamento dal liquor in pazienti affetti da encefalite non è interpretabile come prova sicura di una responsabilità eziologica diretta (che, comunque, si realizza solo in soggetti immunocompromessi) (15). Può provocare un quadro clinico di meningite in concomitanza con la comune malattia esantematica (esantema critico o roseola infantum) (14). Adenoviridae:Adenovirus.Gli adenovirus sono comuni agenti eziologici di infezioni delle alte vie respiratorie e di infezioni gastrointestinali ma, occasionalmente, producono infezioni del SNC in pazienti sia immunocompetenti che immunodepressi (9).…”

Management of acute viral encephalitis in Brazil

“…The first is due to direct viral entry into the CNS leading to neuronal damaging. The second mechanism is triggered by systemic viral infections leading to postinfectious autoimmune response inside the CNS [1].…”