A 52-year-old man comes to the emergency department due to several days of vague chest pain and cough. He immigrated to the United States from Taiwan 20 years ago. Temperature is 37.1 C (98.8 F). Physical examination reveals a decrescendo-type diastolic murmur over the right sternal border. Pulmonary auscultation reveals normal breath sounds with no wheezes or rales. Abdominal examination shows no organomegaly. Serum fluorescent treponemal antibody absorption testing is positive. Chest x-ray reveals mediastinal widening. The pathologic process most likely responsible for this patient's symptoms starts as which of the following?

Question

A 52-year-old man comes to the emergency department due to several days of vague chest pain and cough.  He immigrated to the United States from Taiwan 20 years ago.  Temperature is 37.1 C (98.8 F).  Physical examination reveals a decrescendo-type diastolic murmur over the right sternal border.  Pulmonary auscultation reveals normal breath sounds with no wheezes or rales.  Abdominal examination shows no organomegaly.  Serum fluorescent treponemal antibody absorption testing is positive.  Chest x-ray reveals mediastinal widening.  The pathologic process most likely responsible for this patient's symptoms starts as which of the following?

Quizplus · Accepted Answer

This patient's murmur is characteristic of aortic regurgitation, which, in the presence of mediastinal widening, suggests an aortic aneurysm that has dilated the aortic annulus. The positive serology for syphilis (positive fluorescent treponemal antibody absorption [FTA-ABS] test) suggests a "luetic" aneurysm, consistent with tertiary syphilis. Tertiary syphilis begins with vasa vasorum endarteritis and obliteration, resulting in inflammation, ischemia, and weakening of the adventitia. Aneurysmal dilation of the thoracic aorta results and can extend to involve the aortic valve ring. Syphilitic aneurysms are uncommon in the United States. (Choice A) Intimal streaks are the earliest lesions of atherosclerosis. Severe, complicated intimal atheromas can destroy and weaken the underlying media, resulting in aortic aneurysms. However, the most common site of these lesions is in the abdominal aorta (below the origin of the renal arteries). Although atherosclerosis can promote aneurysm formation in the thoracic aorta, the positive FTA-ABS test makes atherosclerosis less likely to be the cause of this patient's symptoms. (Choices B and C) Intimal tear and medial degeneration (elastic tissue fragmentation and separation of the elastic and fibromuscular components of the tunica media by small, cleft-like spaces) are common histopathologic abnormalities seen with aortic dissections (severe chest pain radiating to the back), not aortic aneurysms. (Choice D) Large vessel arteritides with medial inflammation (eg, Takayasu, giant cell arteritis) might rarely promote an aortic aneurysm; however, they are not associated with a positive serology for syphilis. Educational objective: Tertiary syphilis can result in thoracic aortic aneurysm. If the aneurysm compresses adjacent structures and dilates the aortic valve ring, a murmur and mediastinal widening might be present. The pathogenesis begins with vasa vasorum endarteritis and obliteration, resulting in inflammation, ischemia, and weakening of the aortic adventitia. Fluorescent treponemal antibody absorption testing is specific for syphilis.

A 52-Year-Old Man Comes to the Emergency Department Due to Several