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.
Pyomyositis is recognized more in temperate areas, although still rare. Sadarangani et al. performed a retrospective case review to demonstrate the clinical characteristics of primary pyomyositis in a temperate area, while confirming the aggressive nature of the disease with potentially grave complications and mortality.
From the Departments of *Internal Medicine, †Pediatrics and Human Development, ‡Divisions of Infectious Diseases, Departments of Internal Medicine, and Pediatrics and Human Development, Michigan State University/Kalamazoo Center for Medical Studies, Kalamazoo, MI.
Correspondence to: Sapna Sadarangani MBBS, Departments of Medicine and Pediatrics and Human Development, Michigan State University, Kalamazoo Center for Medical Studies, 1000 Oakland Drive, Kalamazoo, MI 49008. E-mail: firstname.lastname@example.org.
The authors have no funding or conflicts of interest to disclose.
This study received approval from the research committee of Michigan State University/Kalamazoo Center for Medical Studies and from the Institutional Review Board of Borgess Medical Center and Bronson Methodist Hospital where the data were collected.
Waiver of informed consent was obtained because this was a retrospective study.
Ethical approval: S.S. was involved in the study conception and design, data gathering, data analysis, and drafting the manuscript. She is the guarantor of the study.
S.J. was involved in study design, data gathering, and drafting the manuscript. T.M. and T.F. were involved in study conception, design, verification of data analysis, and revision and approval of the final manuscript.