Early Recovery from Cryptogenic NORSE Following Repeated C-NORSE Score Assessment and Cyclophosphamide Treatment.

Cryptogenic new-onset refractory status epilepticus (C-NORSE) is a rare, severe condition characterized by refractory status epilepticus without identifiable causes. It is often unresponsive to first-line immunotherapy. The C-NORSE score is a useful diagnostic tool, but in the early phase, when the score remains low and antibody test results are unavailable, it is difficult to initiate second-line immunotherapy, including cyclophosphamide. We report a 27-year-old man with C-NORSE who achieved early recovery and favorable outcome following administration of intravenous cyclophosphamide, despite a low C-NORSE score on admission, suggesting the importance of repeated assessment using the C-NORSE score and early administration of cyclophosphamide.