Plasma Exchange in Transverse Myelitis
Plasma exchange should be used as add-on therapy for severe transverse myelitis that fails to respond adequately to high-dose intravenous corticosteroids, with the strongest evidence supporting its use when initiated early (within 2 weeks of symptom onset) in patients with baseline EDSS ≤6. 1, 2, 3
Treatment Algorithm
First-Line Therapy
- Initiate high-dose intravenous methylprednisolone immediately upon diagnosis (typically 1000 mg/day for 3-5 days), while excluding infectious causes 1, 4
- Begin treatment within hours of presentation when possible, as delays beyond 2 weeks are associated with worse neurological outcomes 1
Indications for Adding Plasma Exchange
- Inadequate response to corticosteroids after 3-5 days of high-dose IV methylprednisolone 4, 2, 3
- Severe neurological deficit at presentation, including extensive spinal cord involvement (>3 segments), reduced muscle strength, or sphincter dysfunction 1
- Neuromyelitis optica spectrum disorder (NMOSD) with transverse myelitis, regardless of AQP4-IgG status 2, 3
Plasma Exchange Protocol
- Perform 5-10 sessions over 10-14 days, exchanging 1-1.5 plasma volumes per session 1, 2, 5
- Replace with 5% albumin solution or fresh-frozen plasma 1, 5
- Continue maintenance immunosuppression (azathioprine or mycophenolate) to prevent relapses, which occur in 50-60% of cases during corticosteroid taper 1
Evidence Quality and Nuances
The EULAR guidelines for SLE-associated myelopathy specifically mention plasma exchange for severe cases, though the evidence level is limited to case series 1. The strongest research evidence comes from NMOSD populations, where plasma exchange as add-on therapy reduced residual disability (DeltaEDSS 1.2 vs 2.6, p<0.01) compared to steroids alone 2.
Critical predictors of good outcomes at 6 months include:
- Baseline EDSS ≤6 before the attack (OR 58.33,95% CI 1.92-1770) 3
- Early initiation of plasma exchange (OR 6.29,95% CI 1.18-52.96) 6
- Preserved reflexes and minimal disability at baseline 3
- Improvement at hospital discharge (OR 7.32,95% CI 1.21-44.38) 6
Important Caveats
Timing is critical: Delays beyond 2 weeks from symptom onset are associated with severe neurological deficits and poor outcomes 1. Even patients who don't improve immediately may show delayed improvement—48% of non-responders at discharge improved during 6-month follow-up 6.
Safety profile: Plasma exchange has a 3-4% incidence of adverse effects, mostly reversible, with minor events occurring in approximately 24% of sessions 1, 2. The procedure is relatively safe when performed with appropriate monitoring 7.
Context-specific considerations: For SLE-associated myelopathy with antiphospholipid antibodies, anticoagulation therapy should be considered alongside immunosuppression 1. In NMOSD, plasma exchange efficacy is independent of AQP4-IgG antibody status 2.
Combination Therapy
Plasma exchange should not be used as monotherapy 4. Always combine with:
- High-dose corticosteroids (methylprednisolone) 1, 4
- Consider adding cyclophosphamide for refractory cases or when rapid immunosuppression is needed 1, 4
- Transition to maintenance immunosuppression (azathioprine, mycophenolate, or rituximab) to prevent relapses 1
Overall response rate: Approximately 63% of patients with severe CNS demyelination show improvement at 6 months when plasma exchange is added to corticosteroid therapy 6. In NMOSD-specific populations, improvement rates reach 81% at 6 months 3.