A 59-year-old man comes to the emergency department due to 2 hours of vague chest discomfort. The discomfort started suddenly while the patient was watching television. He has no other symptoms. Blood pressure is reported to be under control with hydrochlorothiazide. The patient has a 30-pack-year smoking history. Vital signs are within normal limits. Physical examination shows clear lungs and normal heart sounds but is otherwise unremarkable. ECG is normal. The first set of cardiac enzymes is within normal limits. Chest x-ray is shown in the image below. Which of the following is most likely contributing to the pathophysiology of this patient's condition?

Question

A 59-year-old man comes to the emergency department due to 2 hours of vague chest discomfort.  The discomfort started suddenly while the patient was watching television.  He has no other symptoms.  Blood pressure is reported to be under control with hydrochlorothiazide.  The patient has a 30-pack-year smoking history.  Vital signs are within normal limits.  Physical examination shows clear lungs and normal heart sounds but is otherwise unremarkable.  ECG is normal.  The first set of cardiac enzymes is within normal limits.  Chest x-ray is shown in the image below.  Which of the following is most likely contributing to the pathophysiology of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d175_8718_bc81_1d9e32609b96_MD0003_00 This patient's radiographic findings, including a widened mediastinum, enlarged aortic knob, and tracheal deviation, suggest thoracic aortic aneurysm (TAA). Most TAAs (60%) involve the ascending aorta (between the aortic valve and the brachiocephalic artery), and a minority involve the descending aorta (distal to the left subclavian artery). TAA usually results from age-related degenerative changes that lead to disruption of the aortic wall medial layer with loss of elasticity and consequent aortic dilation. The changes are likely due to a combination of enzymatic breakdown of structural proteins (eg, collagen, elastin) and physical factors such as systemic hypertension and repeated stress from the pulsating arterial wave. Underlying connective tissue disease (eg, Marfan or Ehlers-Danlos syndromes) also increases the risk. Patients with TAA are usually asymptomatic until the discovery is made incidentally on chest x-ray, CT scan, or ECG. However, some patients develop chest or abdominal discomfort as the TAA grows to compress surrounding structures, as in this patient. Dissection (classified based on the location within the aorta) or full-thickness rupture can occur, but this typically has a dramatic presentation with severe pain and often hemodynamic instability. Of note, chest x-ray cannot always distinguish TAA from a tortuous aorta; therefore, chest CT scan with contrast is usually necessary to confirm the diagnosis. Dissection (Choice A) Vasospastic angina typically presents with brief, intermittent episodes of chest discomfort with gradual onset and offset. ECG taken during an episode demonstrates ischemic ST changes. (Choice C) Esophageal motility disorders such as achalasia present with dysphagia to solids and liquids, and chest x-ray may show absence of a gastric bubble. (Choice D) Mallory-Weiss tear commonly presents with hematemesis and epigastric or back pain; the tear is usually precipitated by an episode of nonbloody vomiting with intense retching. (Choice E) Lymphoma can present with mediastinal widening due to hilar/mediastinal lymphadenopathy. However, the enlarged lymph nodes appear as opacities that are discrete from the heart borders. hilar/mediastinal lymphadenopathy (Choice F) Hiatal hernia can be diagnosed by chest x-ray showing a round retrocardiac mediastinal density with air-fluid levels. Patients frequently report symptoms of gastroesophageal reflux (eg, heartburn, regurgitation). chest x-ray Educational objective: Most thoracic aortic aneurysms are due to age-related degenerative changes that lead to disruption of the aortic medial layer, resulting in loss of elasticity and consequent aortic dilation. Chest x-ray often demonstrates a widened mediastinum, enlarged aortic knob, and tracheal deviation. References: Elastin and collagen fibre microstructure of the human aorta in ageing and disease: a review. (http://www.ncbi.nlm.nih.gov/pubmed/23536538) Thoracic aortic aneurysm: reading the enemy's playbook. (http://www.ncbi.nlm.nih.gov/pubmed/18439439)

A 59-Year-Old Man Comes to the Emergency Department Due to 2