Acute hemorrhagic leukoencephalitis: a case report and systematic review of factors associated with severe disability and death.

Introduction: Acute hemorrhagic leukoencephalitis (AHLE), a rare form of acute disseminated encephalomyelitis (ADEM), has a generally poor prognosis. However, significant variation is observed, and even complete recovery has been reported. The recent increase in the frequency of AHLE case reports is possibly contributed by the advent of COVID-19 and may have added to the heterogeneity of cases.

Methods: We report a fatal case of AHLE with a preceding unspecified respiratory infection, then perform a systematic review of AHLE, in an effort to delineate factors that may be associated with an ultimate outcome of severe disability (defined as modified Rankin scale score of 4 or 5) or death.

Results: Descriptions of 31 cases of AHLE were found in 21 identified articles, with our case being the 32nd case. The most common antecedent event was an infection (20 patients, 62.5%), with nearly half of these being COVID-19 (9 patients). The majority of patients had a subacute progression (1 to 10 days) from onset to clinical nadir. We found that an altered mental status (AMS) and a Glasgow Coma Scale (GCS) score of less than 12 were associated with a final outcome of severe disability or death. An abnormal upgoing plantar response was associated with a final outcome of death. COVID-19 and its vaccines were not associated with either outcome.

Conclusion: AMS, depressed GCS, and an upgoing plantar response at presentation may be associated with a poor outcome in AHLE. Our findings may serve as a springboard to much-needed research into the stratification of AHLE.