Status Epilepticus in Patients with Anti-NMDAR Encephalitis Requiring Intensive Care: A Follow-Up Study

To date, specialized studies focusing on status epilepticus (SE) in anti-N-methyl d-aspartate receptor (anti-NMDAR) encephalitis are limited, and the association between the occurrence of SE and clinical outcome is controversial. This study aims to investigate the differences between patients with critical anti-NMDAR encephalitis with SE and patients who experienced epileptic seizures without SE and to evaluate the long-term disease outcomes of patients with anti-NMDAR encephalitis with SE who were admitted to the neurological intensive care unit (neuro-ICU). In this retrospective study based on a prospective registry, patients with anti-NMDAR encephalitis with neuro-ICU admission from 2014 to 2019 were analyzed and divided into two groups based on whether they had SE. Their clinical characteristics during the neuro-ICU stay were assessed and compared. The neurological and seizure outcomes were evaluated every 3 months. Of 83 patients with anti-NMDAR encephalitis, 24 required intensive care. In the SE group, 38.5% (5 of 13) of patients developed refractory SE (RSE), and 21.3% (3 of 13) of patients developed super RSE. More patients in the SE group presented with seizures as the initial symptoms (53.8% vs. 9.1%, p = 0.033) and had a strong positive NMDAR antibody titer in the cerebrospinal fluid (76.9% vs. 27.3%, p = 0.043). More patients in the non-SE group had a good neurological outcome (modified Rankin Scale (mRS) score < 2) at 3 months after disease onset (60.0% vs. 15.4%, p = 0.039), but 83.3% of patients with SE had a mRS score < 2 at 9 months after disease onset, which was similar to the rate in the non-SE group. A total of 41.7% of patients with SE had their last seizure within 1 month from disease onset, which was significantly lower than the rate in the non-SE group (90%), but all the patients with SE became seizure free after the acute phase of disease. Patients with critical anti-NMDAR encephalitis who present with SE have a high rate of RSE/super RSE and recover more slowly than patients without SE, but most of them will eventually achieve good long-term neurological outcomes and live seizure free after the acute phase.