Successful Treatment of Post-coronavirus Disease 2019 (COVID-19) Autoimmune Encephalitis With Plasmapheresis After a Failed Trial of Steroids.

In December 2021, a 58-year-old unvaccinated woman with a past medical history of obesity presented to an outside hospital with severe coronavirus disease 2019 (COVID-19) pneumonia requiring intubation and a prolonged ICU stay. Although she eventually recovered and was extubated, she continued to experience persistent generalized weakness, nausea, weight loss, and mental status changes following discharge. In March 2022, she required re-hospitalization for altered mental status. Her condition progressively deteriorated, rendering her obtunded and nonverbal, responding only to noxious stimuli. After an extensive but unremarkable infectious, neurological, and hematologic workup, she was transferred to our facility for a higher level of care. Post-COVID-19 autoimmune encephalitis was suspected. Despite a trial of intravenous steroids, she remained largely nonverbal, producing only occasional single-word utterances. Following treatment with plasmapheresis, she demonstrated remarkable improvement, speaking in near-complete sentences just one day later and gradually recovering thereafter. It had previously been unclear whether plasmapheresis could serve as an effective treatment for post-COVID-19 encephalitis. We present a case of severe encephalopathy due to post-COVID-19 encephalitis that was successfully treated with plasmapheresis after failure of steroid therapy.