A 72-year-old man comes to the emergency department due to severe chest tightness and dyspnea that started 20 minutes ago at a family dinner. He has never experienced similar symptoms before. The patient's medical conditions include hypertension, hyperlipidemia, type 2 diabetes mellitus, and prostate cancer. He takes multiple medications and has no drug allergies. The patient smoked a pack of cigarettes daily for 30 years and stopped smoking 10 years ago. Chest CT scan with contrast is shown in the image below. Which of the following factors most likely contributed to this patient's current condition?

Question

A 72-year-old man comes to the emergency department due to severe chest tightness and dyspnea that started 20 minutes ago at a family dinner.  He has never experienced similar symptoms before.  The patient's medical conditions include hypertension, hyperlipidemia, type 2 diabetes mellitus, and prostate cancer.  He takes multiple medications and has no drug allergies.  The patient smoked a pack of cigarettes daily for 30 years and stopped smoking 10 years ago.  Chest CT scan with contrast is shown in the image below.  Which of the following factors most likely contributed to this patient's current condition?

Quizplus · Accepted Answer

11ec160b_3993_51ef_9249_0d487b6d9c14_MD0001_00 This patient is experiencing sudden-onset chest tightness and dyspnea, and CT scan of the chest shows a saddle pulmonary embolism (PE) straddling the bifurcation of the main pulmonary artery. The main pulmonary artery, usually comparable in diameter to the ascending aorta, is significantly dilated due to the proximal increase in hydrostatic pressure from the PE. Saddle PE can result in sudden cardiac death or severe hypotension, but many patients can be hemodynamically stable on presentation. Venous thromboembolism (VTE) (ie, PE or deep venous thrombosis) results from the Virchow triad of endothelial injury, venous stasis, and a hypercoagulable state. Malignancy (eg, prostate cancer) induces a hypercoagulable state and is a strong risk factor for VTE. Active smoking is also a risk factor as it contributes to endothelial injury and a hypercoagulable state. Age plays a role as well, as older individuals tend to be more sedentary and are more prone to venous stasis. (Choice A) Atherosclerosis primarily affects the higher pressure arteries in the systemic circulation (eg, aorta, popliteal arteries, carotid arteries) and the coronary arteries. Significant atherosclerosis in the relatively low-pressure pulmonary arteries is rare. (Choice B) Fluid overload causes pulmonary edema, typically appearing as alveolar ground glass opacities on CT scan. This patient's lungs appear clear of airspace disease. (Choice D) An intimal tear can lead to aortic dissection, which classically manifests as severe chest pain radiating to the back. Pulmonary artery dissection is extremely rare. (Choice E) Pulmonary vasculitis (eg, granulomatosis with polyangiitis) could cause dyspnea and chest tightness but would demonstrate an interstitial pattern on CT scan, sometimes leading to pulmonary hemorrhage. (Choice F) Rupture of pulmonary blebs (thin-walled, air-filled subpleural structures) leads to pneumothorax. (Choice G) For pulmonary metastasis to cause significant dyspnea, multiple lesions would likely be present. There is no evidence of lung masses on this patient's CT scan. Educational objective: Saddle pulmonary embolism straddles the bifurcation of the main pulmonary artery. Venous thromboembolism (ie, pulmonary embolism or deep vein thrombosis) arises due to the Virchow triad of endothelial injury, venous stasis, and a hypercoagulable state. Malignancy causes a hypercoagulable state and is a strong risk factor for venous thromboembolism. __________ References: Saddle pulmonary embolism diagnosed by CT angiography: frequency, clinical features and outcome. (http://www.ncbi.nlm.nih.gov/pubmed/17254761) Saddle pulmonary embolism: is it as bad as it looks? A community hospital experience. (http://www.ncbi.nlm.nih.gov/pubmed/21705903)

A 72-Year-Old Man Comes to the Emergency Department Due to Severe