No randomized trials but may include  IVIG, plasmapheresis, corticosteroids, cyclophosphamide and/or rituximab.
Treat underlying malignancy
Limbic encephalitis
Hypoxic encephalopathy
Japanese encephalitis
Acute toxic-metabolic encephalopathy 
Anti-NMDA receptor encephalitis
Hypoglycemia
Drug induced aseptic meningitis
Hyperosmolar state 