USMLE Step 1 - Question 44

A 23 year old male presents to the emergency room with sharp chest pains radiating to his left neck and altered mental status. For the past 3 days he has had severe nausea and vomiting attributed to viral gastroenteritis. Physical examination reveals a loud abnormal scratching sound in end systole and all of diastole located near the cardiac apex. Chest x-ray is normal. His laboratory studies are below:

Serum

Na+ 145 mEq/L
K+  5.4 mEq/L
Cl-  103 mEq/L
HCO3-  22 mEq/L
Urea nitrogen   112 mEq/L
Cr  5.2 mEq/L
Troponin I - negative

Which of the following is likely causing his chest pain?

A. Myocardial ischemia

B. Aortic dissection

C. Esophageal rupture

D. Pericarditis

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