Myalgia

Differential Diagnosis

• Infection:
  • Viral infection (e.g. Influenza)
  • Bacterial infection
  • Spirochete infection (E.g. Dengue fever; Trichinella)
• Drugs:
  • Statins
  • Bisphosphonates
  • Corticosteroids
  • Ciprofloxacin
  • Clofibrate
  • Colchicine
  • Chloroquine
  • Emetine
  • Aminocaproic acid
  • Zidovudine
  • Bretylium
  • Penicillamine
  • Drugs causing hypokalemia
• Metabolic disorders:
  • Vitamin D deficiency
  • Mitochondrial myopathy
  • Scurvy
  • Osteomalacia
• Fibromyalgia
• Endocrine:
  • Hypothyroidism
  • Hyperthyroidism
  • Cushing’s syndrome
  • Adrenal insufficiency
  • Hyperparathyroidism
• Polymyalgia rheumatica
• Rhabdomyolysis
• Myositis (e.g, polymyositis, dermatomyositis)
  • Myositis (peds)
• Systemic lupus erythematosus
• Rheumatoid arthritis
• Inclusion body myositis
• Sarcoidosis
• Scleroderma
• Sjögren’s syndrome
• Psychiatric (e.g. somatic manifestations of depression)
• Domestic abuse
• Crush injury
• Lyme disease
• Ehlers Danlos (Hypermobility syndrome)
• HIV myopathy
• Hypophosphatemia
• Hypokalemia
• Hypothermia
• Prolonged immobility
• Strenuous exercise (overuse) or heat stroke
• Seizure
• Severe volume contraction
• Alcoholism
• Muscular dystrophy
  • Duchenne
  • Becker
  • limb-girdle
  • facioscapulohumeral
  • Myotonic dystrophy
  • Myotonia congenita
• Compartment syndrome; Muscle infarction
• Neuropathic
• Chronic fatigue syndrome
• Vasculitis
• Sarcocystosis
• Spinal stenosis
• Diabetic lumbosacral plexopathy

Evaluation

• Myalgias can be divided into diffuse (systemic) myalgias vs. Localized myalgias.
• Muscle pain can come from Rhabdomyolysis, Myositis, or Myopathy.