624 - Multifocal Osteomyelitis and Spinal Epidural Abscess due to Bacteroides caccae in a Sickle Cell Disease Patient

Publication Number: 624.5716

Mit Shah, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Yara Neaimeh, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Maria Frost, MD Anderson Cancer Center/UT health Houston, Houston, TX, United States; Susan H. Wootton, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States; Faryal Munir, Phoenix Children's Hospital, Phoenix, AZ, United States; Lakshmi Srivaths, University of Texas Health Science Center, McGovern Medical School, Houston, Texas, Houston, TX, United States

Background: Diagnosing osteomyelitis in pediatric patients with sickle cell disease (SCD) is challenging as bone pain is often due to vaso-occlusive episodes. Staphylococcus spp. commonly cause osteomyelitis in non-SCD patients; Salmonella spp. are more frequent in SCD patients. Anaerobic bacteria, like Bacteroides spp., are rare and usually linked to gut mucosal ischemia and bacterial translocation. We report the first case of Bacteroides caccae bacteremia leading to multifocal osteomyelitis and a spinal epidural abscess in a 6-year-old boy with SCD and autism.

Objective: Describing a complex, novel case of B. caccae bacteremia and osteomyelitis in a pediatric patient with SCD and autism

Design/Methods: Case Report

Results: A 6-year-old male with autism and SCD (SS disease) admitted with a 3-day history of right-sided headache. He had two recent hospitalizations: one for pain crises 3 weeks earlier and another for cough and fever 1 week prior. On admission, he was febrile (101.8°F) with leukocytosis (13.7 K/mm³), anemia (6.5 g/dL), procalcitonin (32.26 ng/mL) and CRP (278 mg/L). Physical exam with limited neck range of motion. CSF studies and brain MRI with/without contrast were unremarkable. Chest X-ray revealed a left lower lobe opacity. Broad-spectrum antibiotics (Vancomycin, Ceftriaxone, Azithromycin) were initiated. On hospital day (HD) 3, the patient’s fever continued with new back and leg pain. MRI showed spinal, pelvic, and femoral infarcts, L5/S1 epidural/paraspinal collection and left femoral subperiosteal fluid. On HD 5, B. caccae grew from blood cultures, and antibiotics changed to Meropenem. Patient underwent left femur subperiosteal abscess irrigation and L5 bone biopsy with B. caccae confirmed by 16S PCR from both sites and Karius testing. Bone biopsies showed acute osteomyelitis. By HD 18, Meropenem switched to Metronidazole. Hospital course complicated by persistent febrile episodes, S. mitis/oralis PICC-line associated bacteremia and reduced strength/mobility. Patient discharged on HD 51 with continued improvement in clinical and mobility status, down-trending inflammatory markers, and improvement in osteomyelitis sites except for L5 vertebral body. He received oral metronidazole for 5 months.

Conclusion(s): Anaerobic osteomyelitis in SCD is rare, with few cases linked to B. fragilis. We present the first case of spinal epidural abscess and multifocal osteomyelitis due to B. caccae in a child with SCD. Diagnosis requires high suspicion and proper anaerobic culture techniques. Treatment involves medical and surgical interventions.

Lumbar MRI
Figure 1. A & B: MRI showing L5 epidural and paraspinal abscess (white arrows) on sagittal and axial T2-weighted imaging. C: MRI showing left femoral subperiosteal fluid (white arrows) from the coronal short tau inversion recovery sequence.

PET-CT
Figure 2. PET-CT showed hypermetabolic activity with especially significant FDG uptake at the left distal femur and L5 vertebral body.

Serial Left Femur X-rays
Figure 3. A: Left femur x-ray from 1 week prior to discharge showing focal well-defined area of bone destruction in the distal femur (white arrow). B: Left femur x-ray from 5 months after discharge and 2 weeks after stopping Metronidazole therapy showing resolution of lucencies and improved femur consolidation and bone growth.