The spectrum of myositis and rhabdomyolysis associated with bacterial infection.

OBJECTIVE

(1) To describe the clinical and radiographic features of 6 patients with myositis or rhabdomyolysis associated with bacterial infection. (2) To analyze the role of computed tomography (CT) in myositis associated with bacterial infection.

METHODS

Review of cases treated by the authors with literature review.

RESULTS

Two patients had classical pyomyositis with Staphylococcus aureus as the etiologic agent. One patient had pyomyositis with Enterobacter cloacae (the first reported to our knowledge), 2 had myositis/fasciitis (one due to Clostridium perfringens and one due to S. aureus), and one had fatal toxic rhabdomyolysis in association with C. perfringens bacteremia without evidence of gas gangrene. No patient had a completely normal CT scan of affected muscles, but CT scans in 3 patients failed to show abscesses that were subsequently discovered at surgery, while in another patient CT scanning falsely suggested a large abscess that was not present at surgery.

CONCLUSION

Infection associated muscle involvement represents a spectrum of clinical manifestations that include pyomyositis, myonecrosis, fasciitis/myositis, and toxic rhabdomyolysis. Diagnosis may be delayed by the often mild clinical presentation. CT scanning alone may be unreliable in distinguishing muscle abscess from swollen muscle unless combined with CT guided needle biopsy.