Editors' Note: Prolonged Unconsciousness Following Severe COVID-19

Abstract

Dr. Abdo et al. reported a case series of 6 patients with prolonged but reversible unconsciousness after severe coronavirus disease 2019 (COVID-19) requiring critical care. Brain MRI showed diffuse restricted diffusion in the white matter. Awakening started with early eye opening and flaccid weakness in all cases, with the patients becoming fully responsive and obeying commands between 8 and 31 days after the cessation of sedatives. In response, Dr. Machado notes that the apparent diffusion coefficient of the white matter lesions in these patients was relatively high, suggesting extracellular edema and destruction of myelination. He postulates that these changes could be related to metabolic changes caused by inflammation associated with SARS-CoV-2 infection, and that resolution of the inflammatory syndrome may have allowed recovery of mitochondrial function and subsequent clinical improvement. In another response, Dr. Vogrig et al. suggest nonconvulsive status epilepticus (NCSE) as another potential etiology for the patients' reversible unconsciousness, besides the authors' differential diagnoses of parainfectious or autoimmune encephalitis or critical illness–related encephalopathy. They note that only 2 patients underwent EEG, and none had continuous EEG monitoring. They emphasize that seizures are common in critically ill patients and may not have evident clinical signs and suggest that EEG should be considered in the evaluation of COVID-19 patients with coma. Responding to these comments, the authors agree that NCSE may have been missed. They cite the recent literature on EEG findings in patients with COVID-19 and note that in the largest study, NCSE was seen in 1% of the cases in those patients undergoing continuous EEG. The authors acknowledge that continuous EEG was not available in many of their participating hospitals. This exchange highlights the various potential etiologies that may underlie disorders of consciousness in patients with COVID-19 and the added value of continuous EEG in the evaluation of such patients. Dr. Abdo et al. reported a case series of 6 patients with prolonged but reversible unconsciousness after severe coronavirus disease 2019 (COVID-19) requiring critical care. Brain MRI showed diffuse restricted diffusion in the white matter. Awakening started with early eye opening and flaccid weakness in all cases, with the patients becoming fully responsive and obeying commands between 8 and 31 days after the cessation of sedatives. In response, Dr. Machado notes that the apparent diffusion coefficient of the white matter lesions in these patients was relatively high, suggesting extracellular edema and destruction of myelination. He postulates that these changes could be related to metabolic changes caused by inflammation associated with SARS-CoV-2 infection, and that resolution of the inflammatory syndrome may have allowed recovery of mitochondrial function and subsequent clinical improvement. In another response, Dr. Vogrig et al. suggest nonconvulsive status epilepticus (NCSE) as another potential etiology for the patients' reversible unconsciousness, besides the authors' differential diagnoses of parainfectious or autoimmune encephalitis or critical illness–related encephalopathy. They note that only 2 patients underwent EEG, and none had continuous EEG monitoring. They emphasize that seizures are common in critically ill patients and may not have evident clinical signs and suggest that EEG should be considered in the evaluation of COVID-19 patients with coma. Responding to these comments, the authors agree that NCSE may have been missed. They cite the recent literature on EEG findings in patients with COVID-19 and note that in the largest study, NCSE was seen in 1% of the cases in those patients undergoing continuous EEG. The authors acknowledge that continuous EEG was not available in many of their participating hospitals. This exchange highlights the various potential etiologies that may underlie disorders of consciousness in patients with COVID-19 and the added value of continuous EEG in the evaluation of such patients.