Encephalitis: Difference between revisions

Revision as of 22:00, 12 August 2020

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

Differential Diagnosis

Infectious
- Viruses
- Bacteria
  - Mycoplasma pneumoniae
  - Listeria monocytogenes
  - Borrelia burgdorferi (Lyme disease)
  - Coxiella burnetii
  - Bartonella henselae or B. quintana
- Other
  - Cryptococcus neoformans
  - Toxoplasma gondii
  - Bayliscarias procyonis
  - Prion disease (CJD)
Non-infectious (including post-infectious)
- Acute disseminated encephalomyelitis (ADEM)
- Vasculitis
- Collagen vascular disorders
- Paraneoplastic syndromes

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

Acyclovir for suspected HSV or VZV encephalitis

@@ Line 1: / Line 1: @@
-* Infection of the brain parenchyma causing clouding of the sensorium
+*Infection of the brain parenchyma causing clouding of the sensorium
-* Some overlap with [[meningitis]]
+*Some overlap with [[meningitis]]
-== Differential Diagnosis ==
+==Differential Diagnosis==
-* Infectious
+*Infectious
-** Viruses
+**Viruses
-*** [[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]]
-*** [[Rabies virus]]
+***[[Rabies virus]]
-*** [[Hendra virus]]
+***[[Hendra virus]]
-*** [[Nipah virus]]
+***[[Nipah virus]]
-*** [[Tickborne encephalitis]], [[La Crosse virus]], [[Powassan virus]]
+***[[Tickborne encephalitis]], [[La Crosse virus]], [[Powassan virus]]
-** Bacteria
+**Bacteria
-*** ''[[Mycoplasma pneumoniae]]''
+***''[[Mycoplasma pneumoniae]]''
-*** ''[[Listeria monocytogenes]]''
+***''[[Listeria monocytogenes]]''
-*** ''[[Borrelia burgdorferi]]'' (Lyme disease)
+***''[[Borrelia burgdorferi]]'' (Lyme disease)
-*** ''[[Coxiella burnetii]]''
+***''[[Coxiella burnetii]]''
-*** ''[[Bartonella henselae]]'' or ''[[B. quintana]]''
+***''[[Bartonella henselae]]'' or ''[[B. quintana]]''
-** Other
+**Other
-*** ''[[Cryptococcus neoformans]]''
+***''[[Cryptococcus neoformans]]''
-*** ''[[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
-== Investigations ==
+==Investigations==
-* Lumbar puncture for viral culture or PCR
+*Lumbar puncture for viral culture or PCR
-* MRI is the best neuroimaging; CT if MRI not available
+*MRI is the best neuroimaging; CT if MRI not available
-* EEG is rarely helpful except to rule out non-convulsive status epilepticus
+*EEG is rarely helpful except to rule out non-convulsive status epilepticus
-== Management ==
+=== MRI ===
+{| class="wikitable"
+!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==
-* Acyclovir for suspected HSV or VZV encephalitis
+*Acyclovir for suspected HSV or VZV encephalitis
 [[Category:CNS infections]]