A case of suspected autoimmune encephalopathy with involuntary movements and cognitive dysfunction post‐COVID‐19

Background We report a case of suspected autoimmune encephalopathy with involuntary movements and concomitant cognitive dysfunction after COVID‐19. Case Presentation The patient is a male in his 20s who presented with fever and generalized involuntary movements and was diagnosed with COVID‐19. The involuntary movements improved slightly, and the fever resolved within a week of the diagnosis. However, about a month later, the patient presented with severe recurrence of the involuntary movements. Antiepileptic drugs were ineffective, and the patient was re‐hospitalized with suspected autoimmune encephalopathy. The electroencephalogram (EEG) was difficult to assess accurately due to involuntary movements. Neuropsychological testing on re‐admission revealed mild memory impairment, executive dysfunction, and decreased processing speed. We treated the patient with methylprednisolone (mPSL) 1000 mg/day for a total of 8 days and intravenous immunoglobulin therapy (IVIG) 27.5 g/day for 5 days. Involuntary movements were mild after 59 days. A repeat neuropsychological assessment conducted 3 weeks later showed improvement of both memory and executive functions. The patient was discharged on Day 75, and he returned to work the following month. Conclusion In our patient reported herein, early and appropriate treatment was successful. Impaired activities of daily living and cognitive dysfunction rapidly improved. The case serves to underscore the importance of early detection and intervention for the sequelae of COVID‐19.