A 61-year-old male presented to his primary care physician (PCP) complaining of intermittent chills, fever, and sweats. The patient had undergone a left axillary-bifemoral bypass graft surgery to repair an abdominal aneurysm 6 years prior. This procedure was complicated by a spinal cord infarction and paraplegia. The results of a complete blood count (CBC), a comprehensive metabolic panel (CMP), a thyroid stimulating hormone, and a urinalysis were within normal limits. Blood cultures were not obtained. His symptoms resolved within a few days and further work up was deferred. However, within 2 weeks, the fevers and sweats recurred. The symptoms continued to recur every 2-3 weeks, and each episode lasted 3-4 days. During the episodes, he had fever as high as 39.8  C, chills, and sweats. Over the next 3 months, his CBC and CMP remained within normal limits, but his C-reactive protein and erythrocyte sedimentation rate increased from 2.4 mg/dL and 33 mm/Hr, respectively, to 4.8 mg/dL and 39 mm/Hr. Two blood cultures were negative, and a chest radiograph did not find evidence of infection. Three months after symptom onset, an Indium-111-labeled white blood cell scan with single emission positron computed tomography (SPECT-CT) found focal increased radio-tracer uptake in the axillary-bifemoral graft suggestive of focal infection (Fig. 1A and B).
He was referred to the infectious disease clinic for further evaluation. He denied headaches, respiratory symptoms, abdominal pain, skin rash, gastrointestinal symptoms, and urinary symptoms. He lived in a small town in southeast Iowa and he denied recent travel and contact with sick people, including those with tuberculosis. He had no direct animal exposure although there were several farms within a few miles of his house. He worked as an insurance agent and was indoors most of the day. His blood pressure was 121/75 mmHg, his pulse rate was 109 beats per minute, and he was afebrile. Physical examination was unremarkable except for muscular atrophy and decreased strength in both legs. Repeated CBC and CMP tests were all within normal range. Repeated bacterial, fungal, and mycobacterial blood cultures were negative. CT angiography demonstrated a patent left axillary to femoral artery bypass with fat stranding and a small surrounding rim enhancing fluid collection extending from the level of the diaphragm to the iliac crest (Fig. 2A and B). C. burnetii phase I and phase II IgG antibody titers were > 1:32,768. Phase I and phase II IgM antibody titers were 1:64 and 1:32, respectively. A transesophageal echocardiogram did not show evidence of endocarditis. He was diagnosed with C. burnetii vascular graft infection and started on oral doxycycline 100 mg twice and hydroxychloroquine 200 mg three times a day. He underwent explantation of the axillary-bifemoral bypass graft with reimplantation of a cryopreserved artery graft. Cultures obtained during the procedure were negative but C. burnetii polymerase chain reaction (PCR) performed on explanted vascular graft was positive. Three weeks later, he returned to clinic for new onset of orthopnea and leg edema. Fluid retention, possibly due to hydroxychloroquine, was suspected and his treatment was changed to doxycycline and ciprofloxacin, with a plan to continue treatment for at least 18 months.