A 46-year-old man comes to the emergency department with chest pain and shortness of breath over the last 10 hours. The pain is sharp and does not radiate. He says that taking shallow breaths helps to avoid the pain. He considers himself healthy and has never had symptoms like this before. The patient takes over-the-counter antacids for frequent heartburn. He has a 25-pack-year smoking history, but does not use alcohol or illicit drugs. His father died at age 47 from a heart attack. He works as a long-haul truck driver. His temperature is 36.7 C (98 F), blood pressure is 110/70 mm Hg, pulse is 110/min, and respirations are 31/min. The patient's BMI is 29 kg/m². Electrocardiogram (ECG) shows sinus tachycardia. Chest x-ray is shown: What is the most likely diagnosis in this patient?

Question

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The clinical presentation - pleuritic chest pain, dyspnea, tachypnea, and tachycardia in a long-distance truck driver - is most consistent with pulmonary embolism (PE). Other signs/symptoms of PE include cough, hemoptysis, and/or lower extremity pain or swelling (ie, deep venous thrombosis). Some patients may be asymptomatic or have other non-specific symptoms, and additional testing is required to exclude or confirm the diagnosis. Chest radiographs are frequently abnormal in patients with PE. Findings may include atelectasis, infiltrates, pleural effusions, Westermark's sign (peripheral hyperlucency due to oligemia), Hampton's hump (peripheral wedge of lung opacity due to pulmonary infarction), and Fleischner sign (enlarged pulmonary artery). But the overall sensitivity or specificity of these findings is quite low. Furthermore, chest x-rays may be normal (as in this patient) and are therefore not useful for diagnosing PE, though they are useful to exclude other causes of chest pain and dyspnea such as pneumonia, pneumothorax, aortic dissection, and pericardial effusion. (Choice A) Acute myocardial infarction should always be considered in the differential diagnosis of chest pain and dyspnea in patients who smoke and have a family history of premature coronary heart disease. Such patients should be assessed closely with serial electrocardiograms (ECGs) and cardiac enzymes to rule out myocardial ischemia or infarction. However, the pleuritic chest pain and lack of ischemic ECG changes make this diagnosis less likely. (Choice B) An ascending aortic dissection typically presents with sudden-onset, tearing chest and back pain in the setting of uncontrolled hypertension. Chest radiograph may reveal a widened mediastinum or an irregular aortic contour with inward displacement of atherosclerotic calcification. (Choice C) Peptic ulcer perforation presents with acute abdominal pain with radiation to the back or right shoulder and signs of peritonitis. Upright chest radiograph may reveal pneumoperitoneum (gas within peritoneal cavity) with free air under the diaphragm. diaphragm (Choice D) Patients with pneumothorax (air in the pleural space) typically present with pleuritic chest pain and/or dyspnea. Chest radiographs reveal a peripheral or apical radiolucency, along with absence of lung markings beyond the lung edge. pneumothorax Educational objective: The most common signs and symptoms of pulmonary embolism include dyspnea, pleuritic chest pain, tachypnea, and tachycardia. Chest radiograph is frequently abnormal but has poor sensitivity and specificity for pulmonary embolism, and may be normal. References: Chest radiographic findings in patients with acute pulmonary embolism: observations from the PIOPED Study (http://www.ncbi.nlm.nih.gov/pubmed/8372182) Clinical, laboratory, roentgenographic and electrocardiographic findings in patients with acute pulmonary embolism and no pre-existing cardiac or pulmonary disease (http://www.ncbi.nlm.nih.gov/pubmed/1909617)

A 46-Year-Old Man Comes to the Emergency Department with Chest