Successful diagnosis of an atypical prosthetic vascular graft infection without perivascular abscess: luminal vegetation as the hidden septic source.

A 62-year-old woman with a vascular prosthesis for a common hepatic artery aneurysm (3 years ago) was hospitalized because of a 2-week history of lumbago and fever. Six months previously, she was hospitalized at another medical facility for 1 month because of a fever of unknown pathogenesis. Laboratory examination revealed moderate inflammation with an elevated C-reactive protein level of 6.5 mg/dL and a white blood cell count of 7070/mm3. Initial 8-row multi-detector computed tomography (CT) with contrast agent in the emergency department did not show any focus for the origin of the fever. She was referred to the orthopedic surgery department, and MRI of the pelvis revealed inflammation of the left sacroiliac joint (Figure 1). Her first 2 sets of blood cultures were positive for Streptococcus anginosus . Intravenous administration of ampicillin/cloxacillin sodium was started. She was then transferred to the cardiology department for the evaluation of septicemia, which could have been caused by infectious endocarditis. A transthoracic echocardiogram showed severe aortic regurgitation, which was not seen at the time of previous surgery for the vascular prosthesis (Figure 2A). However, a transesophageal echocardiogram only detected a small degenerative change in the right coronary cusp of the aortic valve, which could be healed …