Purpose of Study: Pyomyositis is a rare but emerging disease in temperate climates. The aim was to describe the clinical presentation, microbiological causes, and treatment outcome of patients with pyomyositis in a temperate area.
Methods: A retrospective case series of 32 patients (9 children and 23 adults) who fulfilled preselected International Classification of Diseases, Ninth Revision codes admitted to 2 tertiary community hospitals in Kalamazoo, MI, from 2000 to 2009.
Results: Fifty percent of patients had multiple muscle groups involved, and lower limb and pelvic muscles were most frequently involved. One third was previously well; the remainder had underlying chronic medical problems. Positive cultures from blood and/or muscle were obtained from 27 of the 32 patients. Staphylococcus aureus was the predominant organism (24/27). Incision and drainage was needed in 81% of the patients. Organism-specific antibiotics were used in all patients who had positive cultures. Ten patients needed care in the intensive care unit. Septic shock, necrotizing pneumonia and empyema, osteomyelitis, septic arthritis, acute renal failure, and deep venous thrombosis were the observed complications. Two adult deaths occurred. More cases of pyomyositis occurred in the latter half of the study period compared to the first half (P = 0.0312).
Conclusion: Physicians should be vigilant about the possibility of this diagnosis even in temperate areas, as it is associated with significant morbidity and complications.