What are the British Society of Rheumatology (BSR) guidelines for treating Juvenile Dermatomyositis (JDM)?

British Society of Rheumatology (BSR) Guidelines for Treating Juvenile Dermatomyositis (JDM)

The BSR guidelines recommend initiating treatment for JDM with high-dose corticosteroids (preferably methylprednisolone pulse 15-30 mg/kg/dose on 3 consecutive days), followed by oral prednisolone 1-2 mg/kg/day weekly, combined with methotrexate 15-20 mg/m², along with sun protection and adequate calcium vitamin D intake. 1

Diagnosis and Assessment

Before initiating treatment, proper diagnosis and assessment are essential:

• All children with suspected JDM should be referred to a specialized center, with high-risk patients requiring immediate/urgent referral 1

• High-risk features include:

  • Severe disability (inability to get off bed)
  • Low muscle strength scores (CMAS <15 or MMT8 <30)
  • Presence of aspiration or dysphagia
  • Gastrointestinal vasculitis
  • Myocarditis
  • Parenchymal lung disease
  • Central nervous system involvement
  • Skin ulceration
  • Requirement for intensive care
  • Age <1 year 1

• Essential investigations include:

  • Muscle enzymes (CPK, LDH, AST, ALT, aldolase)
  • Full blood count and blood film
  • ESR and CRP
  • Myositis-specific and myositis-associated antibodies
  • Renal and liver function tests 1

Treatment Algorithm

Initial Treatment for All Newly Diagnosed JDM Patients:

1. First-line therapy:

   • High-dose corticosteroids: IV methylprednisolone pulse (15-30 mg/kg/dose for 3 consecutive days)
   • Followed by oral prednisolone (1-2 mg/kg/day weekly)
   • Combined with methotrexate (15-20 mg/m², preferably subcutaneous)
   • Sun protection and calcium/vitamin D supplementation 1

2. Monitoring response:

   • Regular assessment of major organ involvement
   • Patient/parent-reported outcome measures
   • Muscle strength and skin disease evaluation 1

For Patients Not Responding to Initial Treatment:

1. Check adherence and tolerance to treatment

2. If intolerant to methotrexate:

   • Change to alternative DMARD such as mycophenolate mofetil (MMF) or cyclosporin A 1

3. If inadequate response despite good adherence:

   • Intensify treatment by adding IVIG, or
   • Add or change to other medications including cyclosporin A, MMF, or biologics (rituximab, infliximab, or adalimumab) 1

For Severe Disease (major organ involvement, extensive ulcerative skin disease):

1. More aggressive initial approach:
   • Consider earlier introduction of additional immunosuppressive agents
   • More intensive monitoring 1

Maintenance and Tapering:

1. When improvement is achieved:

   • Continue methotrexate/MMF or cyclosporin A
   • Gradually wean steroids 1

2. Long-term management:

   • Stop added medications when patient is well and steroids are weaned
   • Consider stopping methotrexate/MMF or cyclosporin A when disease is in remission for minimum 1 year off steroids 1

Disease Monitoring

• All children with JDM should have disease activity (muscle, skin, major organ) assessed regularly using standardized tools like the Disease Activity Score 1
• Disease damage should be assessed at least yearly using a standardized measure such as the Myositis Damage Index 1
• Patient/parent-reported outcome measures should be used at diagnosis and during monitoring 1

Common Pitfalls and Caveats

1. Delayed diagnosis and treatment: Early and aggressive therapy is crucial to prevent or stabilize organ damage and complications like calcinosis, which is associated with significant morbidity due to pain and risk of infection 1

2. Inadequate multidisciplinary care: JDM management requires a multidisciplinary approach including physiotherapists, specialist nurses, and pediatric rheumatologists, with other specialists as needed 1

3. Failure to consider alternative diagnoses: In the absence of cutaneous signs and/or failure to respond as expected to therapy, consider alternative diagnoses including metabolic or mitochondrial myopathies and dystrophies 1

4. Incomplete monitoring: Regular assessment of disease activity and damage using standardized tools is essential for optimal management 1

5. Premature discontinuation of treatment: Methotrexate or alternative DMARD should be continued until the patient is in remission for a minimum of 1 year off steroids 2

6. Inadequate attention to calcinosis: New calcinosis may indicate need for treatment intensification 1

The BSR guidelines emphasize the importance of specialized care centers, standardized assessment tools, and a structured treatment approach to optimize outcomes in children with JDM.