A 55-year-old man presents to the emergency department with severe, tearing back pain that started abruptly 2 hours ago. He describes the pain as maximal at onset and radiating between his scapulae. He has a history of chronic hypertension and hyperlipidemia, which are currently untreated. He also smokes one pack of cigarettes daily and has 3 bottles of beer daily. His blood pressure is 180/100 mm Hg in the right arm and 155/95 mm Hg in the left arm. Physical examination shows a man who appears uncomfortable and is otherwise unremarkable. An electrocardiogram shows nonspecific ST-segment and T-wave changes. Chest x-ray reveals mediastinal widening.
Which of the following is the most likely underlying cause of this patient's presenting condition?
The correct answer is:
C) Chronic hypertension
The clinical presentation of this patient strongly suggests an acute aortic dissection, characterized by severe, abrupt-onset, tearing back pain that radiates to the abdomen and is maximal at onset. While the pain is typically described as anterior chest in location in ascending (type A) dissection, for descending (type B) dissection, the pain is more often experienced in the back. The significant variation in blood pressure between arms, with a higher reading in the right arm compared to the left, is a classic sign of aortic dissection. Additionally, the chest x-ray revealing mediastinal widening and the ECG showing nonspecific ST-segment and T-wave changes further support this diagnosis. Among the risk factors presented, chronic hypertension is the most significant, being present in more than 70% of aortic dissection cases, particularly in older patients. Chronic hypertension weakens the aortic wall over time, making it more susceptible to dissection.
Answer choice A: Alcohol use, is incorrect. While alcohol use can contribute to hypertension, it is not directly linked to the mechanism of aortic dissection.
Answer choice B: Atheroscleroitc plaque rupture, is incorrect. Although atherosclerosis can be a risk factor for aortic dissection, it is not as strong a risk factor as chronic hypertension in this context.
Answer choice D: Nephrolithiasis, is incorrect. Nephrolithiasis typically presents with flank pain and hematuria, which are not consistent with the patient's severe, tearing back pain and the findings of mediastinal widening. Nephrolithiasis is not a risk factor for aortic dissection.
Answer choice E: Tobacco use, is incorrect. Smoking is a significant risk factor for atherosclerosis and can contribute to hypertension, but chronic hypertension is the most important risk factor for aortic dissection.
Key Learning Point
Chronic hypertension is the most significant risk factor for aortic dissection, causing weakening of the aortic wall and making it more susceptible to dissection.
