Herpes simplex encephalitis: Difference between revisions
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==Background== |
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*Infection of the brain parenchyma by [[Herpes simplex virus|HSV]], with a predilection for temporal lobes |
*Infection of the brain parenchyma by [[Herpes simplex virus|HSV]], with a predilection for temporal lobes |
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===Microbiology=== |
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*More commonly caused by [[HSV-1]] than [[HSV-2]] (which more commonly causes [[aseptic meningitis]]) |
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===Pathophysiology=== |
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*About one-third are from primary infection while two-thirds are from reactivation of latent infection |
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===Epidemiology=== |
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*Causes about 10% of [[encephalitis]] cases |
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==Clinical Manifestations== |
==Clinical Manifestations== |
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*Rapidly progressing and can lead to coma |
*Rapidly progressing and can lead to coma |
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==Differential Diagnosis== |
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*Other causes of [[encephalitis]] |
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==Investigations== |
==Investigations== |
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**Normal or slightly low glucose |
**Normal or slightly low glucose |
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**'''HSV PCR''' is confirmatory |
**'''HSV PCR''' is confirmatory |
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**If PCR is negative but suspicion remains high, repeat LP in 3 to 7 days |
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*EEG |
*EEG |
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**Spikes and slow waves over involved areas |
**Spikes and slow waves over involved areas |
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==Management== |
==Management== |
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*May need repeat LP if the first one is negative but suspicion is high |
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*[[Acyclovir]] 10mg/kg q8h IV for 14 days |
*[[Acyclovir]] 10mg/kg q8h IV for 14 days |
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**Ensure adequate hydration and adjust for renal function |
**Ensure adequate hydration and adjust for renal function |
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**May do longer 14-21 days in immunocompetent patients due to high risk of relapse |
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==Prognosis== |
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*15% recover completely |
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*20% have severe neurologic sequelae |
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**Primarily dysnomia and impaired new learning |
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**Also seizures, neuropsychiatric illnesses |
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*28% mortality even with treatment |
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*Prognosis is worse with those who are older, are sicker at presentation, or have delayed treatment |
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[[Category:Herpesviridae]] |
[[Category:Herpesviridae]] |
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Latest revision as of 14:55, 27 April 2021
Background
- Infection of the brain parenchyma by HSV, with a predilection for temporal lobes
Microbiology
- More commonly caused by HSV-1 than HSV-2 (which more commonly causes aseptic meningitis)
Pathophysiology
- About one-third are from primary infection while two-thirds are from reactivation of latent infection
Epidemiology
- Causes about 10% of encephalitis cases
Clinical Manifestations
- Fever
- Headache
- Altered level of consciousness
- Personality and behavioural changes
- Focal neuro deficits
- Seizures
- Rapidly progressing and can lead to coma
Differential Diagnosis
- Other causes of encephalitis
Investigations
- Imaging
- CT head usually normal
- MRI head can show T2 signal change in temporal lobes
- Lumbar puncture
- Elevated protein
- Lymphocytosis (10-1000 WBCs)
- Erythrocytes in 80% of cases ("hemorrhagic necrotizing meningoencephalitis")
- Normal or slightly low glucose
- HSV PCR is confirmatory
- If PCR is negative but suspicion remains high, repeat LP in 3 to 7 days
- EEG
- Spikes and slow waves over involved areas
- Periodic lateralized epiieptiform discharges (PLEDs)
- Usually predominately over involved termporal lobe
Management
- May need repeat LP if the first one is negative but suspicion is high
- Acyclovir 10mg/kg q8h IV for 14 days
- Ensure adequate hydration and adjust for renal function
- May do longer 14-21 days in immunocompetent patients due to high risk of relapse
Prognosis
- 15% recover completely
- 20% have severe neurologic sequelae
- Primarily dysnomia and impaired new learning
- Also seizures, neuropsychiatric illnesses
- 28% mortality even with treatment
- Prognosis is worse with those who are older, are sicker at presentation, or have delayed treatment
