New-onset, rapidly progressive mental status changes of 1-6 weeks, or new-onset seizure activity

Neuropsychiatric changes; agitation, aggressiveness, emotional lability

Autonomic dysfunction (presenting as labile blood pressure, labile heart rate, persistent tachycardia, postural hypertension)

Viral prodrome (runny nose, sore throat, low-grade fever), only to be scored in absence of underlying malignancy

Facial dyskinesias or faciobrachial dystonic movements

Seizure refractory to at least 2 antiseizure medications

CSF findings consistent with inflammation (elevated CSF protein level >50mg/dL and/or lymphocytic pleocytosis >5 cells/dL, if the total number of CSF RBCs is <1000 cells/dL)

Brain MRI showing signal changes consistent with limbic encephalitis (medial temporal T2/FLAIR signal changes)

Presence of underlying malignancy (excluding cutaneous squamous cell or basal cell carcinomas)