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Evidence summaries

Intravenous Immunoglobulin for Exacerbations of Myasthenia Gravis

Intravenous immunoglobulin (IVIg) is probably of limited benefit for exacerbations of myasthenia gravis (MG). In chronic MG there is insufficient evidence from RCTs to determine whether IVIg is efficacious. Level of evidence: "C"

A Cochrane review [Abstract] 1 included 7 studies with a total of 371 subjects. Five trials (n=344) addressed the efficacy of IVIg for the treatment of MG worsening or exacerbation and two (n=27) for treatment of chronic or severe but stable MG. All trials investigated short-term benefit.

  • MG exacerbations: When intravenous immunoglobulin (IVIg) was compared with placebo, mean difference on day 14 in the quantified MG score (QMGS) was -1.60 (95% CI -3.23 to 0.03), being borderline significant in favour of IVIg (1 study, n=51). In an unblinded study (n=87) comparing IVIg and plasma exchange there was no difference in myasthenic muscle score (MMS) after 15 days (MD -1.00; 95% CI -7.72 to 5.72). In the third trial (n=84) there was no difference in change in QMGS 14 days after IVIg or plasma exchange (MD -1.50; 95% CI -3.43 to 0.43). The fourth study (n=33) with moderate exacerbations of MG showed no difference in change in QMGS 14 days after IVIg or methylprednisolone (MD -0.42; 95% CI -1.20 to 0.36). The last trial (n=168) showed no evidence of superiority of IVIg 2 g/kg over IVIg 1 g/kg on the change of MMS after 15 days (MD 3.84; 95% CI -0.98 to 8.66).
  • Chronic or severe but stable MG: In the study with moderate or severe MG (n=12), the mean fall in QMGS both for IVIg and plasma exchange after 4 weeks was significant (p < 0.05). Another study with mild or moderate MG (n=15) found no difference in change in QMGS 42 days after IVIg or placebo (MD 1.60; 95% CI -1.92 to 5.12).

Adverse events due to IVIg were moderate (fever, nausea, headache), self-limiting and subjectively less severe than with plasma exchange (although, given the available data, no statistical comparison was possible).

Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in patients and outcomes) and imprecise results (limited study size, few patients with wide confidence intervals).

References

  • Gajdos P, Chevret S, Toyka KV. Intravenous immunoglobulin for myasthenia gravis. Cochrane Database Syst Rev 2012;12:CD002277. [PubMed].

Primary/Secondary Keywords