Encephalitis: Difference between revisions

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==Differential Diagnosis==
==Differential Diagnosis==


*Common causes include [[HSV]], [[VZV]], and [[enterovirus]] in developed countries
*Consider [[rabies virus]], [[Japanese encephalitis virus]], [[West Nile virus]], [[tickborne encephalitis virus]], and [[St. Louis encephalitis virus]] depending on travel history
*Infectious
*Infectious
**Viruses
**Viruses
***[[Herpes simplex encephalitis|Herpes simplex virus]]
***[[Varicella-zoster virus]]
***[[Enteroviruses]]
***[[Enteroviruses]]
***[[Eastern equine encephalitis|Eastern]] or [[Western equine encephalitis]], [[Japanese encephalitis]], [[Murray Valley encephalitis]], [[St. Louis encephalitis]], [[West Nile virus]]
***[[Eastern equine encephalitis|Eastern]] or [[Western equine encephalitis]], [[Japanese encephalitis]], [[Murray Valley encephalitis]], [[St. Louis encephalitis]], [[West Nile virus]]
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***''[[Toxoplasma gondii]]''
***''[[Toxoplasma gondii]]''
***''[[Bayliscarias procyonis]]''
***''[[Bayliscarias procyonis]]''
***Prion disease ([[CJD]])
***[[Prion disease]] ([[CJD]])
*Non-infectious (including post-infectious)
*Non-infectious (including post-infectious)
**Acute disseminated encephalomyelitis (ADEM)
**[[Acute disseminated encephalomyelitis]] (ADEM)
**Vasculitis
**[[Vasculitis]]
**Collagen vascular disorders
**[[Collagen vascular disorders]]
**Paraneoplastic syndromes
**[[Paraneoplastic syndromes]]
*'''Cryptogenic in 50-70%'''


==Investigations==
==Investigations==

Revision as of 22:04, 12 August 2020

  • Infection of the brain parenchyma causing clouding of the sensorium
  • Some overlap with meningitis

Differential Diagnosis

Investigations

  • Lumbar puncture for viral culture or PCR
  • MRI is the best neuroimaging; CT if MRI not available
  • EEG is rarely helpful except to rule out non-convulsive status epilepticus

MRI

Finding Differential Diagnosis
arteritis and infarctions Varicella-zoster virus, Nipah virus, Rickettsia rickettsii, Treponema pallidum pallidum
calcifications CMV (cortical), Toxoplasma (periventricular), Taenia solium
cerebellar lesions VZV, EBV, Mycoplasma pneumoniae
basal ganglia, thalamus, or brainstem lesions EBV, eastern equine encephalitis virus, Murray Valley encephalitis virus, St. Louis encephalitis virus, Japanese encephalitis virus, West Nile virus, enterovirus A71, influenza virus, prion disease, Tropheryma whipplei, Listeria monocytogenes
hydrocephalus Mycobacterium tuberculosis, Cryptococcus neoformans, Coccidioides immitis, Histoplasma capsulatum, Balamuthia mandrillaris
space-occupying lesions Toxoplasma gondii, Balamuthia mandrillaris, Acanthamoeba species, Taenia solium
subependymal enhancement CMV
temporal or frontal lobe involvement HSV, VZV, HHV-6, West Nile virus, enterovirus, Treponema pallidum pallidum (medial lobes)
white matter abnormalities VZV, CMV, EBV, HHV-6, HIV, Nipah virus, JC virus, measles virus, Baylisascaris procyonis, acute disseminated encephalomyelitis

Management