Plasmapheresis in the treatment of myasthenia gravis: retrospective study of 26 patients.

We analyzed the experience of Unicamp Clinical Hospital with plasma exchange (PE) therapy in myasthenia gravis (MG). About 17.8 % of a totality of MG patients had PE performed: 26 cases, 19 women and seven men. The mean age-onset of MG was 28 years, extremes 11 and 69. Minimum deficit observed in the group was graded IIb (O & G) or IIIa (MGFA scale). One patient had prethymectomy PE. In seven the procedures were performed due to myasthenic crisis and in 18 patients due to severe myasthenic symptoms or exacerbation of previous motor deficit. Two patients were also submitted to chronic PE considering refractoriness to other treatments. Twenty-six patients had 44 cycles of PE and 171 sessions. The mean number of sessions was 3.9 (SD +/- 1.4) each cycle; median 5, extremes 2 and 6. The mean time by session was 106,5 minutes (SD +/- 35.2); median 100.5 (extremes of 55 and 215). The mean volume of plasma exchanged in each session was 2396 ml (SD +/- 561); median 2225 (extremes 1512 and 4500). Side effects occurred: reversible hypotension (seven cases), mild tremor or paresthesias (seven cases). Infection and mortality rates due to PE were zero. All patients had immediate benefit of each PE cycle and usually they also received prednisone or other immunosuppressors. Good acceptance of the procedure was observed in 80.7% of patients.