What is the recommended treatment for acute myelitis?

Treatment of Acute Myelitis

Start high-dose intravenous methylprednisolone (IVMP) immediately once infection is ruled out, and escalate to plasma exchange (PLEX) or IVIG if no improvement occurs within the initial treatment cycle. 1

Initial Acute Treatment Algorithm

First-Line Therapy: High-Dose Corticosteroids

• Initiate IVMP as soon as basic CSF results exclude infection (e.g., cell count patterns inconsistent with bacterial/fungal infection) 1
• This approach is supported by evidence showing significant improvement in independent walking at 1 month and full recovery at 1 year in children with severe acute transverse myelitis 2
• If steroids are contraindicated (uncontrolled hypertension, uncontrolled diabetes, acute peptic ulcer, severe behavioral symptoms), start with IVIG or PLEX instead 1

When to Escalate Treatment

If no clinical, radiological, or electrophysiological improvement by end of initial treatment cycle, add second-line therapy: 1

• Choose IVIG first if:

  • Patient is agitated
  • Bleeding disorders present

• Choose PLEX first (5-10 sessions every other day) if: 1

  • Severe hyponatremia present
  • High thromboembolic risk (cancer, smoking, hypertension, diabetes, hyperlipidemia, hypercoagulable states)
  • Associated brain or spinal demyelination present
  • Patient failed corticosteroid treatment 3

Severe Presentations Require Combination Therapy

For severe initial presentations, start combination therapy (steroids/IVIG or steroids/PLEX) from the beginning rather than sequentially: 1

• Severe NMDAR-antibody presentation
• New-onset refractory status epilepticus
• Severe dysautonomia

Second-Line Immunotherapy

If no improvement 2-4 weeks after combined acute therapy, consider: 1

• Rituximab for known or highly suspected antibody-mediated autoimmunity (e.g., NMDAR-antibody encephalitis, NMO spectrum disorder) 3
• Cyclophosphamide for known or highly suspected cell-mediated autoimmunity (e.g., classical paraneoplastic syndrome) 1
• Tocilizumab may be considered for moderate-to-severe myelitis in NMOSD, as early initiation showed significant improvement in disability scores (EDSS, HAI, mRS) at 3 months compared to steroids alone 4

Critical Diagnostic Considerations That Guide Treatment

Essential Testing Before Treatment

• NMO-IgG (aquaporin-4) antibodies should be tested as they determine both etiology and recurrence risk 3
• MOG antibodies testing helps distinguish MOGAD from other etiologies 5
• Spinal MRI characteristics:
  • Lesions extending >3 vertebral segments suggest NMO vs MS 3
  • This distinction is critical as treatment approaches differ

Age and Clinical Pattern Matter

• Older patients more likely to have spinal infarcts (different treatment paradigm) 3
• Acute complete transverse myelitis (ACTM) vs acute partial transverse myelitis (APTM) distinction helps determine etiology and relapse risk (APTM has higher relapse risk) 3

Common Pitfalls to Avoid

1. Don't delay treatment waiting for antibody results - start IVMP once infection is excluded, as early intervention reduces inflammatory damage 6, 2

2. Don't use steroids alone in severe presentations - combination therapy from the start improves outcomes 1

3. Don't forget to screen for underlying malignancy - perform CT chest/abdomen/pelvis with contrast, as paraneoplastic myelitis requires different management 1

4. Don't miss AFM (acute flaccid myelitis) - this enterovirus-associated variant presents with acute flaccid limb weakness, often with respiratory prodrome, and may require different supportive care including potential nerve transfer surgery for persistent weakness 7, 8

Maintenance Therapy

After acute treatment, bridge with: 1

• Gradual oral prednisone taper, OR
• Monthly intravenous immunoglobulin, OR
• Monthly intravenous methylprednisolone

The specific etiology-based diagnosis (MS, NMOSD, MOGAD, sarcoidosis) will ultimately determine long-term preventive treatment strategy 5.