A 34-year-old man comes to the emergency department due to acute-onset central chest and epigastric pain radiating to the mid-lower back. The pain started an hour ago while at rest. The patient also reports mild shortness of breath and diaphoresis. He has not seen a physician in 10 years. The patient drinks 3 or 4 beers most days and occasionally uses cocaine. His last use of cocaine was a day ago. On examination, the patient is in severe distress due to pain. Skin is cool and clammy. Blood pressure is 210/120 mm Hg and equal in both arms. Pulse is 110/min and regular, and respirations are 22/min. Pulse oximetry shows 95% on room air. BMI is 34 kg/m². There is no pulse asymmetry. Jugular venous pressure is normal. Breath sounds are decreased at the left lower base, and percussion is dull in the same area. Heart sounds are normal with no murmurs or extra sounds. Abdominal and neurologic examinations show no abnormalities. Extremities have no cyanosis, clubbing, or edema. ECG reveals sinus tachycardia with nonspecific T-wave changes. Serum troponin is normal. D-dimer is elevated. Serum lipase is normal. Chest x-ray shows a moderate-sized left pleural effusion. Which of the following is the most likely cause of the patient's current condition?

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11ec25c8_d8a0_8cc1_bc81_e727a2ec0e67_MD0003_00 This patient likely has acute aortic dissection complicated by pleural effusion. Risk factors for aortic dissection include hypertension, connective tissue disorders (eg, Marfan syndrome), and preexisting aneurysm. Cocaine, which can cause rapid and transient hypertension, is frequently associated with dissections in young patients. Patients typically have sudden-onset, severe chest or back pain that is described as sharp or tearing. Depending on the vessels and structures involved (eg, carotid arteries, aortic root, celiac artery), complications can include stroke, acute aortic regurgitation with heart failure, or mesenteric ischemia. Involvement of the subclavian or iliac arteries can result in asymmetry of pulses or blood pressure (pulses and blood pressure are typically symmetric if these arterial branches are not involved). Pleural effusion may occur due to either direct extension causing hemothorax or from an inflammatory reaction to blood irritating the pleural lining. D-dimer elevation is common (sensitive but not specific) due to the presence of fibrin degradation products. ECG findings can be variable depending on the patient's underlying illnesses (eg, hypertension) or the presence of coronary ostia compromise. Plain x-ray may demonstrate a widened cardiac silhouette, and CT scan typically shows an intimal flap or double aortic lumen. widened cardiac silhouette intimal flap (Choices A and E) Myocardial infarction (MI) due to ruptured atherosclerotic plaque is uncommon in young patients (<35), and cocaine-induced MI is usually due to increased myocardial oxygen demand and coronary artery vasospasm. MI due to either mechanism is less likely than aortic dissection in this patient given the normal troponin and moderate-sized pleural effusion. (Choice B) Longitudinal esophageal tear (Mallory-Weiss syndrome) typically presents with hematemesis and epigastric pain in the setting of recent vomiting with retching. (Choice C) Acute necrotizing pancreatitis commonly presents with epigastric pain radiating to the back, often with an associated pleural effusion. However, normal serum lipase makes this diagnosis much less likely. (Choice D) Presentation with chest pain, dyspnea, sinus tachycardia on ECG, elevated D-dimer (again nonspecific), and pleural effusion can be typical of pulmonary embolism. However, the chest pain is usually pleuritic, and hypotension and jugular venous distension are typically present. Epigastric pain and marked hypertension make cocaine-induced aortic dissection a more likely diagnosis. Educational objective: Cocaine can cause rapid and transient hypertension and is associated with aortic dissection in young patients. There is typically sudden-onset, severe chest or back pain that is sharp or tearing, and pleural effusion may occur due to hemothorax. References: Acute aortic dissection and intramural hematoma: a systematic review. (http://www.ncbi.nlm.nih.gov/pubmed/27533160)

A 34-Year-Old Man Comes to the Emergency Department Due to Acute-Onset