P0897 - Salmonella oranienburg osteomyelitis in an immunocompetent adolescent

Introduction: Salmonella causes 0.45% of osteomyelitis cases(1) and is uncommon without predisposing conditions.(2) Vertebral infection with Salmonella is rare.(1,3) We report a previously healthy adolescent with Salmonella oranienburg cervical osteomyelitis.

Case Description: A 15-year-old male presented with several years of intermittent neck pain, which worsened over four days. Associated symptoms included subjective fevers, one day of vomiting, and near-syncope the day prior to presentation. Symptoms were preceded by a febrile respiratory illness two weeks before. He denied sore throat, abdominal pain, diarrhea, weakness, or numbness. Besides playing soccer, he had no trauma. He traveled to Mexico two months prior. His mother recently returned from Malaysia.

On examination, his temperature was 38.3 degrees Celsius. He had bony tenderness over C4 and pain with neck movement. CRP was elevated (73 mg/L). CMP showed mildly elevated transaminases. Viral respiratory panel was negative. He developed leukopenia (1.01x10^3/mcL) and thrombocytopenia (115x10^3/mcL). Neck CT and MRI showed C4 sclerosis and periosteal reaction without local inflammation (Figure 1A). Abdominal ultrasound revealed mild splenomegaly. Full-body MRI showed only the C4 lesion. Nuclear bone scan revealed no scintigraphic evidence of osseous lesions. Differential included chronic osteomyelitis, chronic recurrent multifocal osteomyelitis, Langerhans cell histiocytosis, and neoplasm. Biopsy was explored; due to location, risks were considered higher than empiric treatment. He started doxycycline and rifampin for presumed chronic osteomyelitis. Blood cultures and tuberculosis, histoplasmosis, blastomycosis, brucellosis, coccidiomycosis, and bartonella testing were ultimately negative. MRI five weeks later revealed increased vertebral body destruction and new retropharyngeal and epidural phlegmons (Figure 1B). Fluid from retropharyngeal phlegmon grew Salmonella oranienburg. He transitioned to six weeks of levofloxacin with improvement on MRI.

Discussion: Salmonella osteomyelitis is rare in patients without hemoglobinopathies or immunodeficiencies,(2) accounting for 0.8% of Salmonella infections and 0.45% of osteomyelitis cases.(1) Risk factors include foreign travel, reptile exposure, and ingestion of undercooked poultry or dairy.(2) Our patient recently traveled to Mexico, where meat is frequently contaminated with Salmonella.(2) However, only 14% of previously healthy children with Salmonella osteomyelitis endorsed these exposures.(4) To our knowledge, only five cases of Salmonella oranienburg osteomyelitis are reported in the English literature.(3-6) Interestingly, all cases involved vertebrae. Evidence suggests microscopic vertebral bone infarcts and increased bone marrow activity favor Salmonella growth.(2,4,7) This patient’s diagnosis was challenging, as initial imaging did not show inflammation typical for osteomyelitis. Data on radiographic findings in Salmonella osteomyelitis is limited; however, several cases presented similarly to osteolytic neoplasms.(7)

Conclusion: Salmonella osteomyelitis should be considered in patients with recent travel. This case highlights the importance of gathering a thorough social history, using a multidisciplinary approach, maintaining close follow up, and obtaining tissue samples when the differential remains broad. Our report adds to the paucity of literature regarding Salmonella osteomyelitis in previously healthy children.