The inflammatory myopathies

The inflammatory myopathies

1. benign acute myositis

   • assumed post-viral phenomenon
     • often follows an upper resp tract infection
       • runs a self-limiting course
   • pain & weakness in the affected mm
   • CPK usually raised

2. dermatomyositis

   • systemic illness
     • probably due to an angiopathy
   • onset 5-10 years old
     • acute
     • typically insidious
       • fever
       • misery
       • eventually symmetrical mm weakness
         • mainly proximal
       • pharyngeal mm involvement
         • swallowing affected
       • heliotrope (violaceous) rash
         • characteristic
         • eyelids
         • extensor surfaces of e.g.
           • elbow
       • periorbital oedema
       • subcutaneous calcification
   • Ix
     • raised ESR, CRP possibly
     • muscle biopsy
       • inflammatory cell infiltrate & atrophy
   • Mx
     • physiotherapy
       • prevent contractures
     • corticosteroids
       • mainstay of Rx
       • continue @ tailored dose for 2 years
     • immunosuppressants
       • methotrexate
       • ciclosporin
   • mortality= 5-10%