Usually viral - usually HSV (most common pathogen), VZV and other herpes group viruses, HHV-6, 7, enteroviruses and adenovirus
Limbic encephalitis is a form of antibody-mediated encephalitis
May be associated with underlying malignancy or autoimmune
Clinical features
Fever (90%)
Meningism
Personality and behavioural change, which progresses to a reduced level of consciousness and even coma
Seizures (focal and generalised)
Focal neurological deficits, such as speech disturbance
Investigations
Routine bloods
Blood cultures and viral PCR
Lumbar puncture: CSF analysis with viral PCR
Viral - elevated lymphocytes, viral detection by CSF PCR
Limbic - antibodies may be identifiable
MRI: bilateral medial temporal lobe involvement
Management
Suspected HSV and VZV encephalitis is treated immediately with intravenous acyclovir, even before investigation results are available - significantly improves outcomes
Management of limbic encephalitis depends on cause - treat tumour, immunosuppressive treatment