Polymyositis

Etiology

  • Rare
  • Autoimmune d/o affecting muscles

Risk Factors

  • Female > male
  • Age>20

Symptoms

  • Symmetrical proximal weakness of arms and legs
  • Develops over weeks to months
  • Neck flexor weakness
  • No sensory deficits
  • Sometimes pain, though not prominent feature
  • Dysphagia in 1/3
  • Polyarthritis in 45%
  • SOB if interstitial lung disease

Physical Exam Findings

  • Symmetric proximal > distal weakness
  • Preserved reflexes
  • Dry crackles if interstitial lung disease
  • "Mechanics hands": hyperkeratotic, fissured on palms/lateral aspects

Tests