Encephalitis: Difference between revisions
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+ | *Infection of the brain parenchyma causing clouding of the sensorium |
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− | = Encephalitis = |
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+ | *Some overlap with [[meningitis]] |
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+ | ==Differential Diagnosis== |
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− | == Definition == |
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+ | *Common causes include [[HSV]], [[VZV]], and [[enterovirus]] in developed countries |
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− | * Infection of the brain parenchyma causing clouding of the sensorium |
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+ | *Consider [[rabies virus]], [[Japanese encephalitis virus]], [[West Nile virus]], [[tickborne encephalitis virus]], and [[St. Louis encephalitis virus]] depending on travel history |
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− | * Some overlap with [[Meningitis/Meningitis.md|meningitis]] |
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+ | *Infectious |
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+ | **Viruses |
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+ | ***[[Herpes simplex encephalitis|Herpes simplex virus]] |
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+ | ***[[Varicella-zoster virus]] |
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+ | ***[[Enterovirus|Enteroviruses]] |
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+ | ***[[Eastern equine encephalitis virus|Eastern]] or [[Western equine encephalitis virus]], [[Japanese encephalitis virus]], [[Murray Valley encephalitis virus]], [[St. Louis encephalitis virus]], [[West Nile virus]] |
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+ | ***[[Rabies virus]] |
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+ | ***[[Hendra virus]] |
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+ | ***[[Nipah virus]] |
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+ | ***[[Tickborne encephalitis virus]], [[La Crosse virus]], [[Powassan virus]] |
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+ | **Bacteria |
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+ | ***''[[Mycoplasma pneumoniae]]'' |
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+ | ***''[[Listeria monocytogenes]]'' |
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+ | ***''[[Borrelia burgdorferi]]'' (Lyme disease) |
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+ | ***''[[Coxiella burnetii]]'' |
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+ | ***''[[Bartonella henselae]]'' or ''[[B. quintana]]'' |
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+ | **Other |
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+ | ***''[[Cryptococcus neoformans]]'' |
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+ | ***''[[Toxoplasma gondii]]'' |
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+ | ***''[[Bayliscarias procyonis]]'' |
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+ | ***[[Prion disease]] ([[CJD]]) |
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+ | *Non-infectious (including post-infectious) |
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+ | **[[Acute disseminated encephalomyelitis]] (ADEM) |
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+ | **[[Vasculitis]] |
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+ | **[[Collagen vascular disorders]] |
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+ | **[[Paraneoplastic syndromes]] |
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+ | *'''Cryptogenic in 50-70%''' |
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+ | ==Investigations== |
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− | == Differential Diagnosis == |
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+ | *Lumbar puncture for viral culture or PCR |
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− | * Infectious |
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+ | *MRI is the best neuroimaging; CT if MRI not available |
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− | ** Viruses |
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+ | *EEG is rarely helpful except to rule out non-convulsive status epilepticus |
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− | *** Enteroviruses |
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− | *** Eastern or Western equine encephalitis, Japanese encephalitis, Murray Valley encephalitis, St. Louis encephalitis, West Nile virus |
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− | *** Rabies |
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− | *** Hendra virus |
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− | *** Nipah virus |
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− | *** Tickborne encephalitis, La Crosse virus, Powassan virus |
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− | ** Bacteria |
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− | *** ''Mycoplasma pneumoniae'' |
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− | *** ''Listeria monocytogenes'' |
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− | *** ''Borrelia burgdorferi'' (Lyme disease) |
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− | *** ''Coxiella burnetii'' |
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− | *** ''Bartonella henselae'' or ''B. quintana'' |
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− | ** Other |
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− | *** ''Cryptococcus neoformans'' |
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− | *** ''Toxoplasma gondii'' |
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− | *** ''Bayliscarias procyonis'' |
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− | *** Prion disease (CJD) |
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− | * Non-infectious (including post-infectious) |
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− | ** Acute disseminated encephalomyelitis (ADEM) |
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− | ** Vasculitis |
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− | ** Collagen vascular disorders |
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− | ** Paraneoplastic syndromes |
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+ | ===MRI=== |
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− | == Investigations == |
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+ | {| class="wikitable" |
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+ | !Finding |
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+ | !Differential Diagnosis |
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+ | |- |
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+ | |arteritis and infarctions |
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+ | |[[Varicella-zoster virus]], [[Nipah virus]], [[Rickettsia rickettsii]], [[Treponema pallidum pallidum]] |
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+ | |- |
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+ | |calcifications |
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+ | |[[CMV]] (cortical), [[Toxoplasma]] (periventricular), [[Taenia solium]] |
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+ | |- |
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+ | |cerebellar lesions |
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+ | |[[VZV]], [[EBV]], [[Mycoplasma pneumoniae]] |
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+ | |- |
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+ | |basal ganglia, thalamus, or brainstem lesions |
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+ | |[[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]] |
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+ | |- |
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+ | |hydrocephalus |
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+ | |[[Mycobacterium tuberculosis]], [[Cryptococcus neoformans]], [[Coccidioides immitis]], [[Histoplasma capsulatum]], [[Balamuthia mandrillaris]] |
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+ | |- |
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+ | |space-occupying lesions |
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+ | |[[Toxoplasma gondii]], [[Balamuthia mandrillaris]], [[Acanthamoeba]], [[Taenia solium]] |
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+ | |- |
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+ | |subependymal enhancement |
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+ | |[[CMV]] |
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+ | |- |
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+ | |temporal or frontal lobe involvement |
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+ | |[[HSV]], [[VZV]], [[HHV-6]], [[West Nile virus]], [[enterovirus]], [[Treponema pallidum pallidum]] (medial lobes) |
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+ | |- |
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+ | |white matter abnormalities |
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+ | |[[VZV]], [[CMV]], [[EBV]], [[HHV-6]], [[HIV]], [[Nipah virus]], [[JC virus]], [[measles virus]], [[Baylisascaris procyonis]], [[acute disseminated encephalomyelitis]] |
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+ | |} |
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+ | ==Management== |
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− | * Lumbar puncture for viral culture or PCR |
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− | * MRI is the best neuroimaging; CT if MRI not available |
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− | * EEG is rarely helpful except to rule out non-convulsive status epilepticus |
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+ | *Empiric [[acyclovir]] 10 mg/kg IV q8h for suspected HSV or VZV encephalitis |
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− | == Management == |
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+ | *Add [[doxycycline]] if [[Rickettsiae|rickettsiosis]] or [[ehrlichiosis]] is possible |
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+ | [[Category:CNS infections]] |
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− | * Acyclovir for syspected HSV or VZV encephalitis |
Latest revision as of 12:46, 25 January 2022
- Infection of the brain parenchyma causing clouding of the sensorium
- Some overlap with meningitis
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
- Viruses
- Herpes simplex virus
- Varicella-zoster virus
- Enteroviruses
- Eastern or Western equine encephalitis virus, Japanese encephalitis virus, Murray Valley encephalitis virus, St. Louis encephalitis virus, West Nile virus
- Rabies virus
- Hendra virus
- Nipah virus
- Tickborne encephalitis virus, La Crosse virus, Powassan virus
- Bacteria
- Other
- Viruses
- Non-infectious (including post-infectious)
- Cryptogenic in 50-70%
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
Management
- Empiric acyclovir 10 mg/kg IV q8h for suspected HSV or VZV encephalitis
- Add doxycycline if rickettsiosis or ehrlichiosis is possible