Back Pain and Fever: A Complex Query

A cattle farmer in his 70s, with a history of endovascular abdominal aortic aneurysm repair, presented with a 4-week history of back pain. Sagittal T2-weighted magnetic resonance imaging (MRI) demonstrated fluid in the L1-L2 disc space and erosion of the L2 vertebral body (Figure 1A). Image-guided biopsy yielded negative cultures. Histopathology demonstrated granulomatous inflammation. The patient was started on empiric therapy with intravenous cefepime and metronidazole but developed progressive pain. Because of the presence of a culture-negative process, a query (Q) fever serology was sent. Phase I immunoglobulin G (IgG) titer was strongly positive at 1:16834, with a phase II IgG titer of 1:4096. Before Q fever-directed treatment, follow-up sagittal T2-weighted MRI 8 weeks later (Figure 1B) showed progressive L1-L2 discitis-osteomyelitis, formation of interval epidural abscess, and resultant compression of the cauda equina. Presence of anterior spinal changes on imaging with a vascular graft in situ and positive Q fever serology raised concern for contiguous spread of infection.1Virk A. Mahmood M. Kalra M. et al.Coxiella burnetii multilevel disk space infection, epidural abscess, and vertebral osteomyelitis secondary to contiguous spread from infected abdominal aortic aneurysm or graft: report of 4 cases acquired in the US and review of the literature.Open Forum Infect Dis. 2017; 4: ofx192Crossref PubMed Scopus (5) Google Scholar Fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography with computed tomography (PET/CT) was undertaken and demonstrated FDG uptake within the involved lumbar levels and surrounding paraspinal soft tissues, including around the aortic graft (Figure 2). Transesophageal echo did not demonstrate any valvular vegetation. The patient required surgical L1-L2 decompression and is planned for removal of infected aortic graft, based on involvement shown at PET/CT. Coxiella burnetii-specific polymerase chain reaction tested positive on spinal tissue. Doxycycline and hydroxychloroquine were initiated for treatment of Q fever.2Derrick E.H. The query fever: the Elkington oration.Queensland Health. 1964; 1: 1-20Google Scholar Exposure history of the host is an important consideration in evaluation of infection, and PET/CT is a valuable tool in detecting endovascular complications of this zoonotic infection. The authors report no competing interests.