Abstract
INTRODUCTION: The bacterial pyomyositis (BP) is a rare infectious disease that affects the skeletal muscle system and it is most often caused by S aureus. It affects one or several muscle groups and an early diagnosis is important, otherwise it may cause serious infectious conditions, including sepsis and long-term disabling sequelae and even limb loss. PURPOSE: To describe a case report of a patient with pyomyositis early diagnosed and good evolution. REPORT: 10-year-old patient with severe pain in the lower limbs and in the pelvic girdle and claudication for one day, that started after riding a bicycle for a long period of time. Patient denied fever or general symptoms. Laboratory tests showed an ongoing inflammatory process and blood culture was negative. X-ray and ultrasound of the hip and left thigh were normal, but MRI of the hip showed signs suggestive of bacterial pyomyositis. Intravenous antibiotics were started with fast improvement. Patient was discharged after 21 days of antibiotic therapy, without sequelae. CONCLUSION: The careful clinical history and the magnetic nuclear resonance confirmed the diagnosis of the disease and allowed early institution of the treatment, evolving with no sequelae.