 Case A 68-year-old, well-developed, well-nourished black male presents to the emergency department complaining of shortness of breath. He denies chest pain. He has no significant past medical history and takes no medications. A chest x-ray shows clear lung fields, mild cardiomegaly and a widened thoracic aorta with linear calcifications. An MRI of the chest shows aortic dilatation in the thorax, extending proximally, with atrophy of the muscularis and wrinkling of the intimal surface. What is the most likely etiology of this condition? A. Atherosclerosis B. Hypertension C. Marfan's syndrome D. Syphilis infection E. Takayasu's arteritis Explanation The correct answer is D. Although rare now because of advances in treatment, syphilitic aortitis and aneurysm are still seen, especially in underserved populations. This complication generally occurs 10 to 40 years after initial infection. The vasa vasorum of the aorta undergoes obliterative endarteritis, leading to atrophy of the muscularis and elastic tissues of the aorta and dilatation. Linear calcifications are often seen in the ascending aorta by x-ray. The intimal wrinkling or "tree barking" is also a common feature. Syphilitic aneurysm can be associated with respiratory distress, cough, congestive heart failure and rarely, rupture. Atherosclerosis (choice A) is the most common cause of aortic aneurysms. These are most often located in the abdominal aorta, distal to the renal arteries. Intimal wrinkling and linear calcifications are not seen. Hypertension (choice B) is usually responsible for dissecting aneurysms located within 10 cm of the aortic valve. Patients present with sudden chest pain, which is usually severe and tearing in nature. The chronic hypertension causes a cystic medial necrosis, allowing the separation of vessel layers. Marfan's syndrome, an autosomal dominant connective tissue disorder (choice C) is also associated with dissecting aneurysms, usually of the ascending aorta. The patients are often very tall with arachnodactyly and ligamentous laxity. Their life-span is generally shortened. This patient's description and age are not consistent with this diagnosis. Takayasu's arteritis (choice E) is a syndrome characterized by ocular disturbances and weak pulses in the arms. It occurs most frequently in young females. It is considered a giant cell arteritis, and does not cause aneurysms. 病例分析 一位68岁发育营养良好的黑人男性以呼吸急促为主诉送往急诊科。他没有特殊的医疗史和用药史。胸片显示肺野清晰，轻度心脏扩大和扩张的边缘钙化的胸主动脉。胸部MRI显示胸主动脉扩张，向近心端扩展，伴有肌层萎缩和内膜皱褶。最可能的病因是？ A.动脉粥样硬化 B.高血压 C.马凡综合征 D.梅毒感染 E.大动脉炎 解释 正确答案是D。尽管因为治疗的进步梅毒已经非常罕见，梅毒性主动脉炎和梅毒动脉瘤仍存在，特别是在一些资源匮乏的人群中。这种综合征常在初次感染的10至40年后发病。主动脉的外膜滋养血管发生闭塞性血管炎，导致肌层和动脉弹力组织萎缩以及主动脉扩张。X光片也经常看到升主动脉边缘钙化。内膜皱褶或“树胶样肿”也是常见的特征。梅毒性动脉瘤可导致呼吸疾病，咳嗽，充血性心力衰竭以及罕见的动脉瘤破裂。 动脉粥样硬化（选项A）是主动脉瘤最常见的原因，他们通常发生于腹主动脉，肾动脉的远端。内膜皱褶和边缘钙化不会发生。 高血压（选项B）通常与距主动脉瓣10厘米以内的夹层动脉瘤有关。表现为突发胸痛的病人通常病情严重且动脉瘤已破裂。慢性高血压则导致动脉中膜囊性坏死，从而使血管壁分离。 马凡综合征（选项C），是一个与夹层动脉瘤有关的常染色体显性遗传结缔组织疾病，他的动脉瘤通常发生在升主动脉。该病病人通常身材高挑，指（趾）细长，韧带松弛。他们的寿命通常是缩短的。该病例中病人的描述和年龄与马凡综合征的诊断不符。 大动脉炎（选项E）是以视力障碍和上肢脉搏减弱为特征的综合征。通常发生于年轻女性。它被认为是巨细胞动脉炎的一种，通常不会造成动脉瘤。 |
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