Pyogenic spondylitis due to Streptococcus agalactiae with paraspinal abscess and vertebral destruction in a diabetic patient: time course of imagings

SUMMARY: A 76-year-old female with type 2 diabetes mellitus presented with hematuria, low back pain, and intermittent fever for 7 days. She was admitted to our hospital and diagnosed with Streptococcus agalactiae (GBS) bacteremia. CT showed an air density within the right iliopsoas muscle, and an MRI of the spine revealed hyperintensity in the right half of the L1–L2 intervertebral disk, leading to the diagnosis of a paraspinal abscess and L1–L2 pyogenic spondylitis. Antibiotic therapy was started and the clinical symptoms, as well as serologic biomarkers and radiologic images of the paraspinal abscess, were improved. The therapy was stopped on day 72 despite vertebral destruction progression. Vertebral endplate ossification was observed on day 108, and further bone formation was noted on day 177. Our case study with radiologic findings over 6 months demonstrated how bone destruction with pyogenic spondylitis, which had been treated with antibiotic therapy, improved after cessation of antibiotics. LEARNING POINTS: Although GBS is a rare cause of spondylitis, diabetic mellitus is a risk factor for the development of invasive GBS infections, especially under poor glycemic control. Bone destruction of pyogenic spondylitis can improve after discontinuation of antibiotic therapy. It may be important to decide the period of antibiotic therapy based on clinical conditions, serologic biomarkers, and soft tissue findings rather than bone findings. When elderly diabetic patients present with back pain and fever, spondylitis should be considered in the differential diagnosis to avoid potential diagnostic delays or misdiagnosis.