Rupture of an infected aortic aneurysm with rapid dilatation.

An 87-year-old normotensive man was admitted to our hospital due to symptoms of general fatigue. His body temperature was 37.3°C, his C-reactive protein (CRP) level was 22.6 mg/dL and his white blood cell count (WBC) was 16,000/mL. Although a computed tomography (CT) scan did not reveal any infections, we detected Klebsiella pneumoniae in a blood culture. Following the administration antibiotic treatment, both the CRP level and WBC count decreased, however, the patient’s general fatigue did not improve. A repeat CT scan revealed a large abdominal aortic aneurysm (AAA). Over the following 8-day period (Picture 1), the aortic diameter increased from 27 mm to 70 mm. We suspected an infected AAA owing to the rapid dilatation; hence, emergency surgery was planned. Unfortunately, the patient suddenly went into shock, and we were unable to revive him with cardiopulmonary resuscitation. A postmortem examination revealed a ruptured AAA separated completely above the iliac artery (Picture 2), and microscopy revealed arteriosclerosis, thrombosis and inflammatory cell infiltration (Picture 3). The patient was therefore diagnosed with a ruptured infected AAA.