Case history
A 72-year-old Asian woman was admitted to our hospital with a three-week history of intermittent fever and general fatigue. Her past medical history was notable for moderate mitral valve regurgitation, which was stable and being followed by a cardiovascular surgeon every year with no medication for 10 years. She has undergone total hysterectomy for uterine myoma at the age of 47 years. Three months before admission, transthoracic echocardiography showed moderate mitral valve regurgitation (Figure 1) and no vegetation on any valves. She had no recent medical histories of diabetes mellitus, weight loss, odontotherapy, and skin disease. Moreover, she had no family history of cardiovascular disease, and she did not smoke and drink.
Physical examination showed body mass index of 19.3 kg/m2, body temperature of 38.4 ºC, regular heart rate at 100 beats/ minute, blood pressure of 95/54 mmHg, respiratory rate of 12 breaths/ minute, and oxygen saturation of 98% on room air. She was previously known to have a grade 2 or greater pansystolic murmur at the apex, a Janeway lesion on the sole of the left foot, and no skin lesions. The remainder of the examination, including the range of motion of lumbars and neurologic examination, was unremarkable.
White blood cell count was 5,530/ µL, hemoglobin was 10.3 g/dL, C-reactive protein (CRP) level was 1.43 mg/dL, and erythrocyte sedimentation rate (ESR) was 78 mm/h. All four sets of blood cultures revealed S. warneri . Transesophageal echocardiography showed a 5-mm motile vegetation on the anterior cusp of the mitral valve (Figures 2A and 2B) and mitral valve regurgitation. Contrast-enhanced thoracic and abdominal computed tomography showed no abscess. Brain diffusion-weighted magnetic resonance imagining (MRI) revealed a high-signal area on the left cerebellum (Figure 3). Sagittal short-T1 inversion recovery MRI demonstrated the high-signal lesions on the disk between the 9th and 10th thoracic vertebrae and vertebral bodies (Figure 4). These findings met the two major and three minor Duke criteria for a definitive diagnosis of IE10.
She was treated with initially cefazoline at 2 g every 8 hours. Based on the subsequent antimicrobial susceptibility test results, we changed the antibiotics to intravenous penicillin G four million units every 4 hours for 6 weeks, after the blood culture turned out negative on day 3. On day 14, transesophageal echocardiography showed resolution of the vegetation. She was discharged on day 45 and was continued on treatment with oral amoxicillin 250 mg every 8 hours for 6 months, until the CRP and ESR normalized11.