Number of plasma exchanges and outcome in myasthenic crisis

Abstract

Background: Plasma exchange is an effective therapy for myasthenic crisis (MC); yet the number of exchanges needed is unknown. We set out to examine the relationship between the number of plasma exchanges and clinical outcome in patients experiencing MC. Methods: We retrospectively reviewed patient episodes with ICD 9 and ICD 10 codes for myasthenia gravis and myasthenia gravis exacerbation/crisis in patients admitted to a single center tertiary care referral center from July 2008 to July 2017. These episodes were screened for patients with impending myasthenia gravis crisis and manifest crisis who received plasmapheresis during their hospital course. We performed statistical analyses to determine if increased number of plasma exchanges improves the primary outcome (hospital length of stay), as well as the secondary outcome (disposition to home, skilled nursing facility, long term acute care hospital, or death). Results: There is neither clinically observable nor statistically significant improvement in length of stay or disposition on discharge in patients who received six or greater sessions of plasmapheresis. Conclusions: This study provides class IV evidence that extending the number of plasma exchanges beyond five does not correlate with decreased hospital length of stay or improved discharge disposition in patients experiencing myasthenic crisis.