Primary Pyomyositis Complicated by Bilateral Pyelonephritis in a Healthy Adolescent Boy

Primary pyomyositis is a rare disease in healthy children and young adults. Early diagnosis is difficult because of its subtle and non-specific manifestations. The clinical course is usually benign and systemic dissemination is usually a manifestation in the late stage. We report a 13-year-old healthy boy who suffered from primary pyomyositis. Although the offending microbe was Oxacillin-sensitive Staphylococcus aureus, his response was unsatisfactory. Bilateral pyelonephritis was disclosed after CT scanning. He began to respond to additional Gentamicin treatment. He had an uneventful recovery thereafter and was discharged on the 8(superscript th) admission day. Although systemic extension often occurs late in its course, we should consider early systemic dissemination is when treatments fail or virulent microbes are identified. Systemic re-evaluation and modification of treatment are necessary to reduce morbidity and mortality.