0521779407-17 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:57
1190 Polymyositis and Related Disorders➣Other possible complaints
Fatigue, morning stiffness, anorexia, fever (rare)
Dysphagia
Cough or dyspnea
Arthralgia more common than true arthritis
Raynaud’s phenomenon
➣Physical examination shows proximal muscle weakness
➣Remainder of neurologic exam normal
■Dermatomyositis (DM)
➣Like PM plus rash
Gottron’s sign: pink raised plaques over knuckles, elbows,
knees
➣Heliotrope rash on eyelids
➣Rash in sun-exposed areas
➣Malar
Anterior chest (V sign)
Upper back (shawl sign)
➣Nail fold capillary changes
■Variations
➣Juvenile dermatomyositis
Like DM plus vasculitis (mainly GI)
Subcutaneous calcifications, lipodystrophy
➣DM or PM w/ another collagen vascular disease
SLE, scleroderma, mixed connective tissue disease
➣DM or PM w/ malignancy (any cancer but especially ovarian)
➣Inclusion body myositis (IBM)
More common in older people
Like polymyositis but may have distal or asymmetric weakness
& rarely responds to therapy
tests
Lab Tests
■Blood (essential)
➣Elevated CK, aldolase, AST, ALT, LDH
■Electromyography (usually required)
➣Myopathic changes (IBM may also show neuropathic changes)
Imaging (Discretionary)
■MRI w/T2-weighted imaging or STIR shows inflammation in
involved muscles
■Muscle biopsy (essential to distinguish IBM)
■PM: muscle fiber degeneration & regeneration w/ CD8+lymphocyte
endomyseal infiltrate