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

Abstract

-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.KEY WORDS: plasmapheresis, myasthenia gravis, therapeutics, acceptance, complications. Plasmaférese no tratamento da miastenia grave: estudo retrospectivo de 26 pacientes RESUMO -Analisamos a experiência do Hospital das Clínicas da Unicamp com plasmaferese: (PF) na miastania grave (MG). 17,8 % do total dos casos de MG submeteu-se a PF, 26 casos, 19 mulheres e sete homens. A idade média de início da MG foi 28 anos (extremos 11 e 69). O menor déficit clínico foi IIb (O & G) e IIIa (MGFA).A PF foi indicada no pré-operatório de timectomia em um caso e em sete devido a crise miastênica. Em 18 casos, com MG generalizada e sintomas bulbares ou com exacerbação de déficit prévio, a PF foi indicada como intervenção aguda. Em dois pacientes desse grupo ela foi indicada também em regime crônico de ciclos mensais. Os 26 pacientes submeteram-se a 44 ciclos e a 171 sessões de PF. O número médio de sessões em cada ciclo foi 3,9 (DP ± 1,4); mediana de 5, extremos 2 e 6. O tempo médio de cada sessão foi 106,5 minutos (DP ± 35,2); mediana de 100,5 (extremos 55 e 215).O volume médio de plasma trocado em cada sessão foi 2396 ml (DP ± 561); mediana 2225 (extremos 1512 e 4500). Efeitos colaterais foram reversíveis: hipotensão (sete casos), tremor ou parestesias leves (sete casos). Taxas de infecção e mortalidade devido a PF foram zero. A totalidade dos pacientes teve benefícios imediatos a cada ciclo de PF e usualmente receberam prednisona ou outro imunossupressor. Houve boa aceitação ao procedimento em 80,7% dos pacientes.

Myasthenic crisis: Guidelines for prevention and treatment

“…A series of early, non-randomized studies [54][55][56][57][58] quickly established the beneficial, primarily short-term effect of PE and since then it has gained wide application in acute care setting [33,35,59,60]. The 1986 NIH consensus statement supported the use of PE, and no placebo controlled clinical trials have been conducted [61].…”

Continuous infusion of calcium gluconate in 5% albumin is safe and prevents most hypocalcemic reactions during therapeutic plasma exchange

“…Patients with neurologic conditions appear to be at particularly high-risk of hypotension, presumably due to autonomic involvement by the primary disease process. A recent paper reported a high occurrence of reversible hypotension (27%) during TPE for myasthenia gravis exacerbations [10]. However, an important difference between our study and theirs was that saline was used as replacement fluid for the first half of their procedures, which could have caused hypotension due to decreased oncotic pressure.…”

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“…Another possibility for non-sustainability of the initial response to TPE in this patient could be the irregularity of the administration of TPE. Therapeutic plasma exchange has been reported to be more effective when given in short interval especially on alternate day [12]. The irregularity of TPE in our patient was multifactorial, ranging from unavailability of Cobe spectra TPE kit, faulty cobe spectra machine with delay in repair due to lack of on-site trained engineers, lack of backup equipment to the financial constraint on the part of the patient.…”