From the Guidelines
Plasmapheresis (PLEX) is indicated for seronegative myasthenia gravis, particularly during myasthenic crisis or for rapid symptom control before other treatments take effect, as it can remove circulating autoantibodies that may not be detected by standard testing in seronegative patients. When managing seronegative myasthenia gravis, it is essential to avoid medications that can worsen the condition, such as β-blockers, IV magnesium, fluoroquinolones, aminoglycosides, and macrolides 1. The treatment approach may involve a 5-day course of plasmapheresis or a 2 g/kg course of IVIG over 5 days, alongside corticosteroids like methylprednisolone at 1–2 mg/kg daily, with weaning based on symptom improvement 1. Key considerations for PLEX in seronegative myasthenia gravis include:
- The typical regimen consists of 5-6 exchanges over 1-2 weeks, with each session removing approximately one plasma volume
- PLEX works by removing circulating autoantibodies, including those that may not be detected by standard testing in seronegative patients
- The clinical response to PLEX is often rapid, with improvement typically seen within days, though the effects are temporary (2-6 weeks)
- Potential complications include hypotension, citrate toxicity, bleeding risk, and infection risk from central venous access, so patients should be monitored closely during treatment. In the context of seronegative myasthenia gravis, PLEX should be considered alongside other treatments like immunosuppressants, as it addresses symptoms but not the underlying autoimmune process.
From the Research
Indication of Plex for Seronegative Myasthenia
- The provided studies do not directly address the indication of plasma exchange (PLEX) for seronegative myasthenia gravis (MG) 2, 3, 4, 5, 6.
- However, some studies discuss the use of PLEX in patients with myasthenia gravis, including those with moderate to severe disease 2, 3.
- One study compared the efficacy of intravenous immunoglobulin (IVIg) and PLEX in patients with moderate to severe MG, and found that both treatments were effective and well-tolerated 3.
- Another study discussed the use of eculizumab and rituximab in patients with generalized myasthenia gravis, but did not specifically address the use of PLEX in seronegative patients 4.
- A review of maintenance immunosuppression in MG mentioned plasmapheresis as an option, but did not provide specific guidance on its use in seronegative patients 5.
- A case series reported the use of double-filtration plasmapheresis and rituximab in patients with refractory MG, but did not specify the serological status of the patients 6.