Table 1 Diagnosis of juvenile dermatomyositis and case definitions
Statements | Consensus |
|---|---|
Diagnosis | 100% |
For the diagnosis of juvenile dermatomyositis, the following findings should be present prior to age 18 years: • Typical skin finding (heliotrope and/or Gottron-sign/−papules) Additional criteria: • Symmetric proximal muscle weakness and/or myalgia • Increased muscle-related enzymes (creatine kinase, glutamate oxaloacetate transaminase, lactate dehydrogenase and/or aldolase) • Typical findings on muscle biopsy • Typical findings on magnetic resonance imaging Other possible etiologies should be excluded. Probable JDM: Skin findings and at least 2 additional criteria Definite JDM: Skin findings and at least 3 additional criteria | |
Case definition | 92% |
The treatment strategies discussed below apply to patients with active moderately severe or severe juvenile dermatomyositis. Patients with severe juvenile dermatomyositis fulfill at least one of the following characteristics and none of these characteristics is present in patients with moderate JDM: • Age < 1 year • Requirement for intensive care therapy • Marked disability as measured by being bedridden, childhood myositis assessment scale (CMAS) < 15 or manual muscle testing (MMT)8 < 30 • Relevant pulmonary disease • Myocarditis • Vasculitis with organ involvement (gastrointestinal tract, kidney, lungs or central nervous system) • Aspiration or marked dysphagia • Severe cutaneous ulceration • Significant calcinosis | |
Diagnostic work-up | 100% |
Obtaining the following parameters may be useful in case of probable or definite JDM: • Laboratory tests: o Enzymes (creatine kinase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, lactate dehydrogenase, aldolase) o Complete blood count with differential count o Routine serum chemistry panel o Inflammatory markers (C-reactive protein, erythrocyte sedimentation rate) o Antinuclear antibody (ANA) o In case of positive ANA: anti-ds-DNA, anti-PM-Scl, Sm antibodies, anti-SS-A, anti-SS-B and anti-U1RNP antibodies o Extended myositis-blot/myositis-specific antibody (incl. Anti-synthetase, anti-MDA5, anti-Mi-2, anti-NXP-2, anti-SRP, anti-TIF-1-γ antibodies) o Immunoglobulin (Ig)G, IgA, IgM o Complement (CH50) o Von Willebrand factor-antigen o Troponin o TSH o Immunization status o Urinalysis o Stool for occult blood • Further testing: o Electrocardiography o Echocardiography o Magnetic resonance imaging (incl. Short tau inversion recovery or equivalent sequences) o Chest X-ray o Abdominal ultrasound o Muscle ultrasound o Muscle biopsy o Bodyplethysmography with CO-diffusion capacity o Capillary microscopy |