Obturator pyomyositis and labium majus cellulitis: A case report and literature review.

Pyomyositis is a rare, subacute, deep bacterial infection of the skeletal muscle. When treatment is delayed, pyomyositis causes abscess formation and progresses to sepsis; therefore, its early diagnosis is important. However, the clinical presentation and laboratory findings of pyomyositis are not specific; hence, diagnosis often takes time. We encountered the case of a girl with obturator pyomyositis and redness and swelling of the labium majus, which we considered as potentially important symptoms for distinguishing obturator pyomyositis from septic hip arthritis. An 8-year-old Japanese girl presented to our hospital with fever and right hip pain. On physical examination, she had redness and swelling of the right labium majus and a right limp. She was diagnosed with obturator pyomyositis and labium majus cellulitis with magnetic resonance imaging. Her clinical presentation markedly improved after starting antibiotic therapy with intravenous cefazolin for 2 weeks and oral cefaclor for 1 week. Improvement in the inflammation of the obturator muscle and labium majus was confirmed with follow-up magnetic resonance imaging. She recovered fully with no long-term sequelae. In conclusion, obturator pyomyositis rather than septic hip arthritis should be considered in children with a limp and hip and perineal pain, particularly girls with redness and swelling of the labium majus. In addition, imaging studies, including magnetic resonance imaging, should be performed for early diagnosis.
Competing Interests: Declaration of conflicting interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The authors declare no conflicts of interest related to this study. However, outside the submitted work, Ichiro Morioka has received lecture fees from MSD Co., Ltd., Shionogi Co., Ltd., and AbbVie LLC and study grants from Atom Medical Corp.
(© The Author(s) 2022.)