A 47-year-old man is brought to the emergency department after being involved in a high-speed motor vehicle collision. He was a restrained driver and rear-ended a slow-moving car on the highway. He complains of chest pain, abdominal pain, and difficulty breathing. The patient has a past medical history of hypertension, asthma, and type 2 diabetes mellitus. On arrival, his blood pressure is 98/54 mm Hg and pulse is 121/min. Thirty minutes later, he becomes unresponsive and his pulse is no longer detectable. Electrocardiogram demonstrates sinus tachycardia. Despite extensive resuscitation efforts, the patient dies. An autopsy would most likely show an injury involving which of the following areas of the thoracic aorta?

Question

A 47-year-old man is brought to the emergency department after being involved in a high-speed motor vehicle collision.  He was a restrained driver and rear-ended a slow-moving car on the highway.  He complains of chest pain, abdominal pain, and difficulty breathing.  The patient has a past medical history of hypertension, asthma, and type 2 diabetes mellitus.  On arrival, his blood pressure is 98/54 mm Hg and pulse is 121/min.  Thirty minutes later, he becomes unresponsive and his pulse is no longer detectable.  Electrocardiogram demonstrates sinus tachycardia.  Despite extensive resuscitation efforts, the patient dies.  An autopsy would most likely show an injury involving which of the following areas of the thoracic aorta?

Quizplus · Accepted Answer

11ec160b_3554_bde4_9249_bbc71b8287c9_MD0001_00 This patient's presentation is consistent with blunt aortic injury (ie, traumatic aortic rupture), which is most commonly caused by motor vehicle collisions. The mechanism of injury involves a sudden deceleration that results in extreme stretching and torsional forces affecting the heart and aorta. Injury occurs most often at the aortic isthmus, which is tethered by the ligamentum arteriosum and is relatively fixed and immobile compared to the adjacent descending aorta. The majority (>80%) of patients die from aortic rupture before reaching the hospital. Those who survive the initial injury have nonspecific findings such as chest pain, back pain, or shortness of breath. A widened mediastinum may also be seen on chest x-ray. (Choices A and B) Traumatic aortic ruptures can also affect the ascending aorta and are associated with especially high mortality due to associated complications (eg, hemopericardium, coronary artery dissection, aortic valve disruption). However, the aortic isthmus is by far the most common site of blunt aortic injury. (Choices D and E) The distal descending aorta is a less common site for rupture than the more proximal portions of the aorta. Educational objective: Traumatic aortic rupture is most often caused by the rapid deceleration that occurs in motor vehicle collisions. The most common site of injury is the aortic isthmus, which is tethered by the ligamentum arteriosum and is relatively fixed and immobile compared to the adjacent descending aorta. __________ References: Blunt thoracic aortic injuries: an autopsy study (http://www.ncbi.nlm.nih.gov/pubmed/21217494) Fatal aortic rupture from nonpenetrating chest trauma. (http://www.ncbi.nlm.nih.gov/pubmed/22481840)

A 47-Year-Old Man Is Brought to the Emergency Department After