• Primary bacterial infection of skeletal muscle
  • Also known as myositis tropicans, more common in tropical settings
  • Temperate climates in immune compromised patients
  • Mainly disease of children, age 2-5 most common


Risk Factors

  • DM
  • HIV
  • IVDU
  • Renal failure
  • Immunosuppression

Clinical Features

More commonly affects proximal lower extremity muscles

First stage

  • Localized muscle pain, low grade fevers, vague complaints[2]
    • Localized muscle inflammation without abscess

Second stage

  • Worsening pain, muscle swelling, fever, abscess formation

Third stage

Differential Diagnosis

Skin and Soft Tissue Infection



  • CBC
  • Chem 10
  • PT/PTT
  • CK
  • Lactate
  • CT extremity with contrast
  • Ultrasound
  • MRI, study of choice
  • Surgical exploration is gold standard


  • IV antibiotics alone for first stage
  • Surgical debridement plus antibiotics for abscess
  • IV fluids, pressors, airway management, rapid debridement for septic shock


  • Admit

See Also


  1. Chauhan, S. (2004) ‘Tropical pyomyositis (myositis tropicans): current perspective’, Postgraduate Medical Journal, 80(943), pp. 267–270.
  2. Scharschmidt, T. J., Weiner, S. D. and Myers, J. P. (2004) ‘Bacterial pyomyositis’, Current Infectious Disease Reports, 6(5), pp. 393–396.