[Group B streptococcal vertebral osteomyelitis following superficial suppurative thrombophlebitis]

An 80-year-old woman with type II diabetes mellitus was admitted to hospital with high-grade fever and leg pain for the previous three days. Physical examination revealed marked distention of the peripheral veins in both lower legs and she complained of pain. Spontaneous superficial suppurative thrombophlebitis was diagnosed and transfusion of cefazolin every 8 hours was started immediately after blood cultures. After 48 hours, the distention of the peripheral veins was improved; however, she suffered from a severe back pain thereafter. Two sets of blood culture yielded Group B streptococcus. Therefore the antibiotic was changed to ampicillin every 6 hours. To investigate the cause of back pain, MRI of the lumbar vertebral body was taken. Saggital gadolinium T1-weighted MRI demonstrated a high signal intensity lesion from Th7 to Th11, suggesting vertebral osteomyelitis following Group B streptococcal bacteremia from superficial suppurative thrombophlebitis. One week later, the clinical symptoms mostly disappeared. After six weeks of treatment, she was discharged. Suppurative thrombophlebitis is an inflammation of the vein wall by microorganisms and sometimes causes secondary metastatic abscess. Aging and diabetes are also risk factors for group B streptococcal invasive infection. This case suggests vertebral osteomyelitis should be taken into consideration during the course of group B streptococcal bacteremia in an elderly patient complaining back pain.