Fulminant Clostridium septicum Aortitis
An 87-year-old man was admitted to our cardiothoracic surgical service complaining of epigastric and interscapular pain of 3 days’ duration. His temperature was 101°F; white blood cell count, 19 100/mm3; and hemoglobin, 11.3 gm/dL. An ECG and serial cardiac enzyme measurements were negative for myocardial ischemia. An echocardiogram demonstrated normal left ventricular function, mild aortic stenosis, and mild biatrial enlargement. Mediastinal enlargement on chest film prompted a CT scan of the chest and abdomen. A gas collection dissecting the outer layer of the aortic wall was identified from the level of the left subclavian artery all the way down to the intra-abdominal aorta ≈2 cm above the celiac axis (Figure 1). Small bilateral pleural effusions were noted, but no ascites or free air was identified, and the structures within the upper abdomen were unremarkable. Blood cultures were drawn and empirical broad-spectrum antibiotics started. A barium swallow and upper gastrointestinal endoscopy ruled out any infection or perforation of the esophagus. On day 3 after admission, the patient complained of increased upper abdominal pain not relieved by morphine. A repeat CT scan showed a dramatic increase in the gas collection dissecting within the wall. The large amount of gas surrounding the descending thoracic aorta was associated with left periaortic fluid and soft tissue density. Four days after admission, blood cultures drawn on admission grew anaerobic gram-positive rods, speciated to be Clostridium septicum, and therapy with clindamycin and ofloxacin was immediately started. The patient further developed diffuse abdominal tenderness and the onset of renal failure with a creatinine level rising from 1.1 mg/dL to 1.8 mg/dL. He and his family refused any invasive procedures, and he died on the sixth hospital day.
Autopsy showed severe calcified atherosclerosis of the thoracic and abdominal aorta, with aneurysmal dilation and extensive aortic dissection extending proximally from the right innominate artery and distally to the renal arteries. Aortic rupture at the level of the carina on the right side had resulted in a right hemothorax. The entire length of the dissection was notable for acute inflammatory exudates associated with gram-positive bacilli (Figure 2). In addition, a 6-cm moderately differentiated adenocarcinoma of the cecum, invading the subserosal fat and involving one omental lymph node was present, a finding consistent with the reported 85% incidence of Clostridium septicum infections associated with gastrointestinal or hematologic malignancy.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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