Positron emission tomography in the diagnosis of disseminated pyomyositis due to PVL-negative methicillin-resistant Staphylococcus aureus

摘要

A 55-year-old woman with myelodysplastic syndrome was admitted because of pyrexia and bilateral lower limb muscle pain. The creatine kinase (CK) was 1152 U/l (reference range: 40-161 U/l). Urine for myoglobin was positive. Blood culture grew methicillin-resistant Staphylococcus aureus (MRSA), sensitive to vancomycin, fusidic acid, clindamycin and erythromycin. She was treated with intravenous vancomycin (1 g every 12h). Computed tomography (CT) of pelvis and lower limbs showed inflammatory changes in the thighs. She was discharged after 7 days of vancomycin treatment, with the CK normal and blood culture negative. She was re-admitted a week later because of recurrent pyrexia. There were multiple indurated lesions over her right lateral thigh, right forearm, left calf and the left scapular region. An ulcer was noted around the umbilicus. The para-umbilical ulcer swab and the left scapular lesion aspirate again grew MRSA. To determine if there was a primary focus causing seeding to multiple sites, a positron emission tomography (PET)-CT was performed. It showed multiple abscesses without an apparent predominant lesion (Figure 1A).