Case presentation
A 30-year-old man was admitted to the hospital with intermittent fever for three months. He had received antibiotics for 6 weeks due to the negative culture endocarditis 3 years ago. At admission, his temperature was 38 degrees centigrade with normal vital signs. Abnormalities in the physical examination were mild cyanotic lips, hyperpigmentation (lipodermatosclerosis) in both legs, splenomegaly, and a mid-systolic murmur in the second left intercostal space. In his past medical history, he had blood culture-negative endocarditis twice in 25 and 27 years of age and also TOF early in his life. His past surgical history consists of Blalock-Taussig shunt in 1994, tetralogy of Fallot total correction (TFTC) in 2001, pulmonary valve replacement (PVR) with a bioprosthetic valve in 2010, and Bentall procedure for native aortic valve endocarditis (NVE) along with mechanical PVR in 2015. In all three surgeries, pathological results were positive for infection and endocarditis [15]. There was not a history of animal contact, recent travel, or any suspicious contact, he just mentioned eating local cheese occasionally and he was the only person with fever in his family.
According to the history of BCNE in our patient and a documented fever, we performed several examinations to rule out infective endocarditis. In early laboratory data, white blood cell count was 5700 × 109/L (4000-10000 × 109/L) with 58% polymorphonuclear leukocytes, hemoglobin level was 12.1 gr/dL (13-16 gr/dL), platelet cell count was 124000 (150,000 to 450,000 platelets per microliter), serum creatinine was 2 mg/dL (0.6-1.5 mg/dL), erythrocyte sedimentation rate was 120 mm/h (0-15 mm/h), and C-reactive protein was 31 mg/L (<6 mg/L).
Urine analysis, viral markers, Coomb’s wright, and 2ME tests were all negative. Other examinations such as Covid-19 PCR and blood culture (six times) were also negative.
We found right axis deviation, first degree atrioventricular (AV) block, right bundle branch block (RBBB), and left posterior hemiblock on his electrocardiography (ECG). The chest spiral computed tomography (CT) scan was normal and without any pathologic findings. In TEE we didn’t find any particular evidence regarding IE and his ejection fraction (EF) was 40%.
According to the former history of BCNE in this patient, the history of PET/CT scan involvement, and also the European heart association guidelines in endocarditis, PET/CT scan was performed. Hyper metabolic lesions were seen over the aortic and pulmonary prosthetic valves along with ascending aorta graft, aortic arch, and proximal root of pulmonary artery involvement, all in favor of infective endocarditis, diffuse increased metabolic activity of sternum which may represent osteomyelitis and also right sub-pectoral adenopathy (Figure 1). Based on modified Duke’s Criteria in this patient, our suspicion was more towards endocarditis.
After the PET/CT scan report, we have performed other examinations to find the organism responsible for BCNE especially brucellosis and Q fever due to the region we practice. Blood and sera samples of this patient were referred to the National Laboratory for Plague, Tularemia, and Q fever of Pasteur Institute of Iran. The Real-time PCR and IFA (IgG phase I; 1:16384, IgG phase II; 1:16384) were positive for C. burnetii and Q fever endocarditis was confirmed. We also examined the previous samples from the last valve replacement for C. burnetii, which was also positive. After the diagnosis, the proper treatment with doxycycline 100mg every 12 hours and hydroxychloroquine 200mg every 8 hours was initiated and the patient’s fever was resolved.
We discharged our patient with the stable condition, suggested to follow up his status with intermittent serological testing every three months and PET/CT scan, a consultant with cardiologist and infectious disease specialist and prescribed doxycycline 100mg every 12 hours and hydroxychloroquine 200mg every 8 hours for 2 years due to the prosthetic valve with a regular eye examination.
In three months, follow-up patient’s inflammatory indices such as ESR and CRP were within normal ranges, C. burnetii serologic test, and sternum uptake in PET/CT scan were decreased.