A retrospective cohort study of plasma exchange in central nervous system demyelinating events in children

Background: Plasma exchange (PLEX) may improve recovery of acute central nervous system (CNS) demyelinating events related to multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), transverse myelitis (TM), acute disseminated encephalomyelitis (ADEM), and MOG-antibody associated demyelination (MOG) if recovery with pulse steroids (PS) is incomplete. Although there is a single randomized controlled trial in adults, there are limited case series in children. We aimed to describe the effectiveness and safety of PLEX in children with acute events of MS, NMOSD, TM, ADEM, and MOG with limited improvement after PS. Methods: This was a retrospective cohort study of children with acute CNS demyelinating events seen at a single tertiary referral center who received PLEX as a second- or third-line therapy between 2006 and 2018. Through chart review of clinical notes, presence of clinical improvement by physician assessment was recorded pre- and post-PS and pre- and post-PLEX. Expanded Disability Status Scale (EDSS) scores were collected pre- and post-PLEX. We evaluated the number who improved clinically with PLEX and compared pre- and post-PLEX EDSS with Wilcoxon matched pairs signed-rank test. Results: 26 patients followed at the Pediatric MS Center at the University of California, San Francisco received PLEX for acute events of MS (n = 15), NMOSD (n = 7), MOG (n = 2), TM (n = 1), and ADEM (n = 1). At time of PLEX initiation, median age was 13.5 years (range 3-17) and median time between the acute event onset and PLEX initiation was 22 days (range 3-94). 14 of 24 patients had documented clinical improvement after PS. Of those who improved during PS (n = 14), 13 had additional improvement after PLEX. Of those with no improvement after PS (n = 10), 8 improved after PLEX. 16 of 26 patients had pre- and post-PLEX EDSS scores available. Median pre-PLEX EDSS score was 4.0 (range 3.0-8.0), and median post-PLEX EDSS score was 3.75 (range 0-8.0) (p = 0.062). 5 patients had improved EDSS scores by 1 or more points. Adverse events during PLEX included hypotension (n = 3), nausea (n = 2), headache (n = 2), hypocalcemia (n = 2), hypofibrinogenemia (n = 2), thrombocytopenia (n = 1), spinal cord hemorrhage (n = 1), acute non-occlusive thrombosis of internal jugular vein (n = 1), occlusion of the central line (n = 1), edema of the neck (n = 1), and gastrointestinal discomfort (n = 1). Conclusions: PLEX is an overall well-tolerated second-line treatment option for pediatric patients with severe acute CNS demyelinating events with limited response to PS.