When to increase the usual steroid (corticosteroid) dose in patients with myasthenia gravis?

When to Increase Corticosteroid Dose in Myasthenia Gravis

Corticosteroid dose in myasthenia gravis should be increased during exacerbations, when respiratory function deteriorates, when bulbar symptoms worsen, or when there is inadequate response to current therapy. 1

Monitoring Parameters for Dose Adjustment

Regular monitoring is essential to identify when steroid dose increases are needed:

• Respiratory Function Indicators:

  • Negative Inspiratory Force (NIF) between -20 to -60 cm H₂O (normal is more negative than -60 cm H₂O)
  • Forced Vital Capacity (FVC) <80% predicted with symptoms or <50% without symptoms
  • Peak Cough Flow (PCF) <270 L/min 1

• Clinical Signs Requiring Dose Increase:

  • Worsening muscle weakness
  • Increasing difficulty swallowing or speaking
  • Respiratory compromise
  • Inadequate response to current therapy
  • Disease relapse during tapering 2

Steroid Dosing Protocol for Exacerbations

1. For Acute Exacerbations:

   • Increase to pre-relapse dose immediately
   • For severe exacerbations, consider high-dose IV methylprednisolone 2g every five days 3
   • Improvement typically begins 2-3 days after infusion with this approach 3

2. For Gradual Worsening:

   • Increase oral prednisone to 0.5-1.5 mg/kg daily 1
   • Monitor closely for initial paradoxical worsening, especially in elderly patients with bulbar symptoms 4

Special Considerations

• Risk Factors for Steroid-Induced Exacerbation:

  • Older age
  • Predominantly severe bulbar symptoms
  • Low Myasthenia Gravis Severity Scale score 4

• Tapering After Exacerbation:

  • Once improvement is achieved, decrease gradually over 4-8 weeks to the dose at which relapse occurred 5
  • Continue tapering by 1 mg every 4 weeks (or using alternate-day schedules) once stable 5
  • The rapid-tapering regimen (when used with azathioprine) has shown better outcomes than slow-tapering 6

• Timing of Administration:

  • Administer in the morning before 9 am to minimize adrenal suppression 2
  • For nighttime symptoms, consider divided dosing 5

Monitoring During Dose Adjustments

• Follow-up visits every 4-8 weeks during the first year of treatment 5
• Monitor for steroid-related side effects, comorbidities, and evidence of relapse 5
• Ensure patients have direct access to healthcare providers to report any changes in their condition 5

Adjunctive Therapies

• Consider early introduction of steroid-sparing agents (methotrexate, azathioprine, mycophenolate mofetil) to minimize steroid exposure 1
• For moderate to severe generalized weakness, consider IVIG 2 g/kg IV over 5 days or plasmapheresis as alternatives to increasing steroid dose 1

Remember that steroid dosing must be individualized based on disease severity, patient response, and risk factors for adverse effects. Close monitoring is essential during dose adjustments to balance efficacy against potential complications.