What is the initial approach to managing chronic myelitis?

Initial Management of Chronic Myelitis

The initial approach to managing chronic myelitis should begin with MRI of the spine area of interest without and with IV contrast, as this is the most appropriate imaging modality to evaluate the underlying cause and guide treatment decisions. 1

Diagnostic Approach

Imaging

• MRI spine without and with IV contrast is the preferred initial imaging modality for chronic myelitis 1

  • Helps visualize spinal cord edema, enhancement patterns, and extent of lesions
  • Can identify specific etiologies (demyelination, vascular malformations, tumors)
  • Superior to CT for visualization of the marrow and spinal cord

• If MRI findings suggest arachnoid cyst/web or ventral cord herniation:

  • CT myelography can be performed for further evaluation 1
  • Positional MRI with flexion/extension may be indicated if positional myelopathy is suspected 1

Laboratory Evaluation

• Cerebrospinal fluid analysis to evaluate for:

  • Inflammatory markers (cell count, protein, glucose)
  • Oligoclonal bands
  • Specific antibodies (AQP4-IgG, MOG-IgG) 2
  • Infectious pathogens

• Serum studies to rule out:

  • Autoimmune disorders
  • Infectious causes (before starting immunosuppression) 3
  • Paraneoplastic syndromes

Treatment Algorithm

First-Line Treatment

• High-dose intravenous methylprednisolone (1g/day for 3-5 days) as soon as possible after diagnosis 3
  • Aims to reduce inflammation and prevent further damage
  • Should be initiated promptly for better outcomes

Second-Line Options

If inadequate response to steroids, consider:

• Intravenous immunoglobulin (IVIG) 2g/kg divided over 5 days 3
• Plasma exchange (5-10 sessions every other day) 3

Third-Line/Refractory Cases

For patients who fail to respond to first and second-line treatments:

• Cyclophosphamide for refractory cases 3
• Rituximab, especially for AQP4-IgG positive patients 3

Maintenance Therapy

• Long-term immunosuppressive therapy is crucial to prevent relapses 3
• Options depend on the specific etiology of myelitis:
  • For MS-related myelitis: disease-modifying therapies
  • For AQP4-IgG positive NMOSD: rituximab or other immunosuppressants
  • For MOG-IgG associated disease: tailored immunosuppression

Symptomatic Management

• Neuropathic pain: pregabalin, gabapentin, or duloxetine 3
• Spasticity: baclofen, tizanidine, or physical therapy 3
• Autonomic dysfunction: monitor for cardiac arrhythmias, blood pressure fluctuations, and urinary retention 3

Important Considerations

Etiology-Specific Approach

• If infectious cause is suspected, antimicrobial therapy should be initiated promptly
  • For parasitic infections like Schistosomiasis: Praziquantel plus dexamethasone 3
  • For viral myelitis: antiviral drugs upon identification of viral pathogen 4

Prognostic Factors

• Better prognosis associated with:

  • Early treatment initiation
  • Prompt neurological response
  • Absence of extensive MRI lesions 3

• Poorer prognosis associated with:

  • Extensive lesions on spinal MRI
  • Reduced muscle strength or sphincter dysfunction at onset
  • Delayed initiation of treatment 3

Monitoring

• Regular assessment for treatment response and side effects
• Evaluation for remission to determine if treatment can be tapered or discontinued
• Follow-up MRI to assess lesion evolution and response to treatment

Pitfalls to Avoid

• Delaying treatment while awaiting complete diagnostic workup
• Failing to rule out compressive etiologies, which require surgical intervention 5
• Starting immunosuppression without ruling out infectious causes
• Discontinuing maintenance therapy too early, risking relapse

By following this algorithmic approach to the management of chronic myelitis, clinicians can optimize outcomes by ensuring prompt diagnosis and appropriate treatment based on the underlying etiology.