Pyomyositis of extraocular muscle: Case series and review of the literature

Pyomyositis is a primary acute bacterial infection usually caused by Staphylococcus aureus. Any skeletal muscle can be involved, but the thigh and trunk muscles are commonly affected. Only three cases of extraocular muscle (EOM) pyomyositis have been reported. We herein present four cases of isolated EOM pyomyositis. Three of our cases presented with acute onset of proptosis, pain, swelling and redness. One patient presented with mass in the inferior orbit for 4 months. One patient had central retinal artery occlusion on presentation. None of them had marked systemic symptoms. Computed tomography scan of all patients showed a typical hypodense rim enhancing lesion of the muscle involved. Three patients were started on intravenous antibiotics immediately on diagnosis and the pus was drained externally. Two patients underwent exploratory orbitotomy. In conclusion, it should be considered in any patient presenting with acute onset of orbital inflammation. Management consists of incision and drainage coupled with antibiotic therapy