[A dissecting aortic aneurysm involving a right-sided aortic arch].

A 51-year-old woman suddenly developed severe pain in the chest and back, also dyspnea. On admission, she was in a state of preshock. Plain X-ray indicated the lack of the left aortic arch and poor pneumatization in the whole right lung. The thoracic fluid was transparent with yellowish tinge and was contaminated with neither any bacterium nor tubercle bacillus. The response to the Rivalta's reaction was negative. The possibility of pleurisy was, therefore, denied. The ECG and blood biochemical data on the second day suggested the possibility of myocardial ischemia. Plain chest X-ray on the fourth day revealed an increased right pulmonary pneumatization and an enlarged mediastinal shadow toward the aortic arch. Upper pulmonary CT showed a mass on the right side. Enhanced CT disclosed a dissepiment in the center, which was high medially and somewhat low laterally. It was diagnosed as a false lumen due to the lateral displacement of the right aortic arch. Hepatic CT disclosed the tapering of the abdominal aorta from right to left in the prevertebral region. These findings indicated that the aorta descended from the right aortic arch along the right side of the spine and crossed the spine dextrosinistrally at the hepatic level. In addition, dissociant aneurysm was observed in the right aortic arch. Echocardiography showed no evidence of dissociant aneurysm at the aortic base. Chest X-ray, CT and echocardiography showed the dissociation of the aorta from the aortic arch to the abdominal aorta. Thus the diagnosis of De Bakey type III was established. Clinically, DIC and multiorgan disorders were manifested but after medical treatments, the clinical course was uneventful.(ABSTRACT TRUNCATED AT 250 WORDS)