When do you start cyclophosphamide for the treatment of anti-NMDA receptor encephalitis?  

First-line immunotherapy for anti-NMDA receptor encephalitis includes high-dose steroids, intravenous immunoglobulin (IVIg), and plasma exchange (PLEX), sequentially or concurrently. Second-line immunotherapy includes a trial of rituximab first and then cyclophosphamide due to the serious side effec...