Effect of Intravenous Immunoglobulin or Plasmapheresis in Myasthenic Crisis and Worsening Myasthenia Gravis Compared to Without Rescue Treatment.

PURPOSE: There is a paucity of studies on intravenous immunoglobulin (IVIg)/plasmapheresis (PLEX) compared with no rescue treatment (NRT) in myasthenic crisis (MC) and worsening myasthenia gravis (WMG). We report the efficacy of RTs (IVIg and PLEX) compared with NRT in MC/WMG.

METHODS

Patients with MC and those having worsening in the MG Foundation of America classification by ≥2 grades were included. Their clinical findings, precipitating causes, and MG Activity of Daily Living (MGADL) and MG Quality of Life (MGQoL)-15 scores were noted. Patients were either treated with IVIg (400 mg/kg/d for 5 days) or PLEX (20-25 mL/kg × 5 sessions), and nonaffording patients received only standard care. The primary outcome was improvement in MG Foundation of America classification by ≥2 grades, and the secondary outcomes included MG Activity of Daily Living score, MG Quality of Life-15 score, Myasthenia Muscle Score, and days of mechanical ventilation (MV), hospital stay, and reaching pre-worsening status at 1 month.

FINDINGS: Forty-four patients were included; 19 had MC and 25 had WMG. They were treated for MG for 2 to 19 years. Forty-one (93.2%) patients achieved the primary end point; 22 (95.7%) in RT and 19 (90.5%) in NRT (P = 0.60). The overall odds ratio of RT for the primary outcome was 1.20 (95% CI, 0.70-23.50; P = 0.13). The RT group had an overall hazard ratio of 0.93 (95% CI, 0.37-2.40; P = 0.96) for duration of MV, had hospital stay of 0.78 days (95% CI, 0.34-1.94; P = 0.80), and achieved pre-worsening MG status in 0.99 days (95% CI, 0.40-2.40; P = 0.72) compared with NRT after adjusting for age, triggers, dose of acetylcholine esterase inhibitors (AChEIs), and azathioprine at baseline. PLEX had an edge over IVIg in reducing the duration of MV and hospital stay, but overall hazard ratio was not significant. The RT group, however, required a lower dose of AChEIs (P = 0.04). Ten patients had mild adverse effects.

IMPLICATIONS: All the patients with MC and WMG improved irrespective of RT or NRT, and the RT group required a lower dose of AChEIs at 1 month. A multicenter randomized controlled trial may confirm these observations.