New-onset refractory status epilepticus mimicking herpes virus encephalitis.

New-onset refractory status epilepticus (NORSE) is a recently defined clinical entity that describes patients who present with status epilepticus of unclear etiology that is highly refractory to therapy. Magnetic resonance imaging (MRI) of NORSE usually discloses no specific abnormalities except for an occasional mild T2/FLAIR hyperintense signal of the mesial temporal lobe. Here, we report a peculiar case of NORSE in which brain MRI showed massive alteration of both temporal lobes, with features strongly supporting the diagnosis of herpes virus encephalitis, but lacking any laboratory evidence of viral infection in the blood and cerebrospinal fluid. It showed also striking signal alterations in the thalamus, which got worse in the course of the disease. This report emphasizes the possibility that seizure activity alone plays a critical role in both determining the disease and whether it will be self-sustaining.