myalgia (muscle pain)

Etiology

• muscle trauma
  • exercise
  • muscle tears, tendon tears
• myopathy
  • hypothyroidism
• viral infections
• fibromyalgia
• polymyalgia rheumatica
• connective tissue disorders
  • rheumatoid arthritis
  • systemic lupus erythematosus
  • polyarteritis nodosa
  • scleroderma
  • mixed connective tissue disease
  • polymyositis, dermatomyositis
• pharmaceutical agents:
  • amphotericin B
  • chloroquine
  • clofibrate
  • glucocorticoids
  • oral contraceptives
  • ACE inhibitors
  • aromatase inhibitors (50% of women treated with aromatase inhibitors)
  • many others

History

• see pain
• associated weakness
• associated arthralgias

Laboratory

• complete blood count (CBC)
• erythrocyte sedimentation rate (ESR)
• electrolytes (chem 7 panel)
• serum creatine kinase
• thyroid function studies
  • serum TSH
  • free T4 or free thyroxine index
• serum Ca+2, serum Mg+2, serum phosphate & serum albumin

Diagnostic procedures

• electromyography (if muscle weakness)
• muscle biopsy

Differential diagnosis

• bone pain may be difficult to distinguish

Management

• specific measures for specific etiology
• general
  • rest, ice for first 72 hours
  • > 72 hour, heat generally more helpful
  • pharmaceutical agents
    • acetaminophen
    • NSAIDs
  • physical therapy

More general terms

• musculoskeletal pain

More specific terms

• delayed-onset muscle soreness
• muscle cramp
• myalgia/arthralgia as part of multisystem disease

Additional terms

• fibromyalgia syndrome (fibromyositis, fibrositis)
• muscle weakness
• muscular disease; myopathy
• pharmaceutical agents associated with myalgia
• polymyalgia rheumatica (PMR)