Criteria

Description

1

Positive diagnosis of influenza

Influenza infection is surely present

2

Clinical manifestations

Neuropsychiatric symptoms appear for the first time during the recovery from influenza or 2 to 3 weeks after the onset of influenza: personality changes, seizures, delirium, hallucinations, gibberish, limb weakness or dyskinesia, etc.

3

Laboratory

CSF cell number increased, lymphocyte hyperplasia, protein can be slightly increased or normal

4

Brain imaging

The EEG may show diffuse slow electrical activity

5

Best treatment practice

Intravenous immunoglobulin (IVIG) (e.g., 400 mg/kg daily for 5 days); intravenous methylprednisolone; plasma exchange