Review Question - QID 107672

This patient has acute onset tearing chest pain in the setting of a widened mediastinum on chest radiograph. This presentation is most concerning for an acute aortic dissection, which should be evaluated with a thoracic and abdomen CT angiogram.

An aortic dissection is caused by a tear in the intima layer of the aorta with accumulation of blood in a false lumen (Illustration A), which can propagate proximally (causing complications such as aortic regurgitation or cardiac tamponade) or distally (causing end-organ ischemia from involvement of the thoracic and/or abdominal branches of the aorta). It is important to determine an acute ascending thoracic aortic dissection (Stanford type A), which requires emergent surgical evaluation versus a descending thoracic aortic dissection (Stanford type B), which can be managed medically in hemodynamically stable patients without complications (Illustration B).

McGonaghy and Oza review acute chest pain in adults. The differential diagnosis for chest pain includes acute myocardial infarction, musculoskeletal chest pain, gastroesophageal reflux disease, panic disorder, pericarditis, pneumonia, pulmonary embolism, and acute aortic dissection. Classic symptoms for an acute aortic dissection involve tearing chest pain with radiation to the back. On physical exam, a difference in pulse pressure between the upper extremities can be appreciated. A chest radiograph will often demonstrate a widened mediastinum.

Tran and Khoynezhad review the management of type B aortic dissection. The most important first line medications are beta-blockers, which control the patient’s blood pressure as well as reduce left ventricular contraction, preventing further dissection. Commonly utilized beta-blockers include labetalol, esmolol, metoprolol, and atenolol. The goal heart rate should be less than 60/min and the goal systolic blood pressure should be less than 100 mmHg. Medications such as nicardipine, hydralazine, and sodium nitroprusside can cause reflex tachycardia and are generally avoided in acute aortic dissection.

Figure A demonstrates a widened mediastinum on chest radiograph. Illustration A demonstrates a cross-section of an aortic dissection. Illustration B demonstrates a Stanford type A versus type B dissection.

Incorrect Answers:
Answer 1: This patient’s symptoms cannot be explained by gastroesophageal reflux disease or another primary esophageal disorder.
Answer 2: In hemodynamically unstable patients, an emergent transesophageal echocardiogram can be performed to diagnose an acute aortic dissection.
Answer 3: The lack of dynamic electrocardiogram changes and an indeterminate troponin in this patient makes an acute myocardial infarction less likely in this patient.
Answer 5: This patient’s presentation cannot be explained by pathology of the thoracic or lumbar spine.