Abstract
Primary pyomyositis is a pyogenic and uncommon infection of skeletal muscle, which is mainly observed in tropical areas and/or human immunodeficiency virus patients. In non-human immunodeficiency virus infected patients, the most common cause is diabetes mellitus. Because of its rarity, the accurate diagnosis is often challenging. Staphylococcus aureus is the most common causative bacteria. According to the severity, pyomyositis is divided into three stages, and the late stage is occasionally lethal. The present case was compatible with the most advanced stage. Therefore, it was very difficult to save her life without precise and timely diagnosis. Furthermore, in the invasive stage, surgical drainage and broad-spectrum antibiotics should be given for a long enough period. Here, we report a case of a Japanese woman who developed disseminated abscesses under poorly controlled diabetic conditions accompanied by ketoacidosis, but was successfully treated without any sequelae.