Audio Qbank – Q18 – A 32M with excruciating chest pain

A 32-year-old man is brought to hospital after 20 minutes of acute-onset shortness of breath and excruciating chest pain radiating to the back. He has a history of cocaine use. He is promiscuous and does not use condoms. He was treated with an oral antibiotic for a genital infection last year. His vitals are: temperature 38.3C (100.9F), HR 110, BP 154/50. The left radial pulse is impalpable. There are diffuse crackles heard across both lung fields. A 3/6 holodiastolic murmur is auscultated along the left sternal border. CXR shows a somewhat widened mediastinum. Which of the following is the most likely diagnosis?