Revision as of 18:12, 25 March 2014 by Alinker (talk | contribs) (links)


  • Inflammatory myopathy
  • Affects proximal muscles > distal
  • Female:Male; 2:1
  • Peak incidence 40-50s

Clinical Features


  1. Proximal greater than distal weakness
  • Deltoid and hip flexors
  • difficulty standing from a chair
  1. Onset over months
  2. Mild myalgias


  1. Heliotrope rash on face scalp
  2. Gottron's papules (rash on MCP, PIP, and DIP joints)
  3. Shawl sign (rash above shoulders)


  1. Cardiac (cardiomyopathy)
  2. High association with malignancy
  3. Interstial lung disease

Differential Diagnosis

Polymyositis SLE Guillain-Barre Syndrome Drug Induced Myopathies (Statins) Hypothyroidism Limb Girdle Muscular Dystrophy Rhabdomyolysis Myesthenia Gravis Pyomyositis Viral myositis Botulism


  • CK
  • ANA
  • Chem for creatinine
  • Troponin, can involve myocardium
  • EKG
  • Bedside PFTs (FEV1 and FVC)
  • UA for myoglobin
  • Consider malignancies


  • Severe disease: Respiratory muscle symptoms of CHF
    • Methylprednisolone 1000mg/day x 3 days
  • Mild disease: Prednisone 1mg/kg/day (up to 80mg/day)
    • Taper after 6-8 weeks


  • Admit to monitored bed for CHF symptoms, respiratory muscle weakness
  • Admit for dysphagia/aspiration risk
  • Out patient follow up with muscle biopsy for others

See Also

Weakness Polymyositis SLE Rheumatoid arthritis


Up to Date