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Volume 42, Number 6, December 2009

Clinical characteristics of pyomyositis in children: 20-year experience in a medical center in Taiwan

Min-Chun Hsieh, Nan-Chang Chiu, Hsin Chi, Fu-Yuan Huang

Received: May 12, 2007    Revised: July 14, 2008    Accepted: August 31, 2008   


Corresponding author:

Dr. Nan-Chang Chiu, Department of Pediatrics, Mackay Memorial Hospital ,92, Sec. 2, Chung-Shan North Rd, Taipei, Taiwan. E-mail:


Background and purpose: 

Pyomyositis is an acute pyogenic infection of skeletal muscle. Because of its rarity, pyomyositis can be a diagnostic challenge. The clinical characteristics of pyomyositis were delineated in this study.



The medical records of patients younger than 18 years who were admitted to hospital from 1986 to 2005 and had a discharge diagnosis of pyomyositis were reviewed. The clinical presentations, laboratory data, and diagnostic tools were analyzed.



Twenty four patients were enrolled. The mean ± standard deviation age was 5.3 ± 4.5 years. There were 13 boys and 11 girls. Eight patients (33.3%) had a preceding history of muscle trauma or local injection of the involved area. Five patients (20.8%), had underlying diseases identified. The most common presentations were fever (83.3%) and local swelling (33.3%). Ultrasound was done for 21 patients (87.5%) and provided a definite diagnosis for 20. Twenty patients (83.3%) had positive pus and/or blood culture results. The most common causative organism was Staphylococcus aureus (n = 14; 58.3%). Gram-negative organisms were isolated from 3 patients, all of whom had underlying diseases. Three patients (12.5%) received antibiotic therapy alone and 21 (87.5%) required aspiration or surgical incision and drainage. All patients recovered without sequelae.



Suspicion of pyomyositis is needed for children with previous trauma or injection when they have fever and local swelling of the muscles. Although S. aureus is the most common pathogen of childhood pyomyositis, Gram-negative organisms should be considered as possible pathogens in patients with underlying diseases.


Key words:

Pyomyositis; Staphylococcus aureus; Ultrasonography