Article in Japanese

Case of obturator internus and externus pyomyositis

Masatoshi NAKATA, Yoshie NAKAMURA, Akira KUMAKURA, Takakazu YOSHIOKA, Atsuko HATA, Daisuke HATA

Obturator pyomyositis is a rare subacute muscle infection that is often mistaken for septic arthritis. This report describes a 10-year-old girl with a four day history of fever and right hip pain. She was admitted to our hospital for scrutiny. Her severe pain restricted adduction and extension of right hip joint. Laboratory examinations revealed a CRP of 5.1 mg/dl and ESR of 34 mm/h. An MRI scan showed a low signal intensity on T1-weighted images and high intensity of T2-weighted images in the right obturator internus and externus muscles, suggesting the diagnosis of right obturator pyomyositis. The patient received a 14-day course of intravenous ceftriaxone with subsequent oral cefpodoxime proxetil treatment for two weeks. She completed four weeks of treatment. Eighteen months after presentation, the patient remained free of symptoms with full range of motion of the right hip.
Hip pain may occur secondary to septic arthritis, synovitis, and numerous other conditions. Differential diagnosis should include obturator pyomyositis, although it is rare. Early diagnosis, established with MRI, can support successful treatment using antibiotics.

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Department of Pediatrics, Tazuke Kofukai Medical Research Institute, Kitano Hospital

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Received	November 8, 2011
Accepted	February 19, 2012

24 (2)：171─174,2012