A 67-year-old obese male presents to the emergency department with sudden onset of severe left-sided abdominal pain that radiates to the left flank and back. The pain began 2 h ago while he was watching television. He has never had the pain before. He denies any nausea or vomiting, changes in bowel habits, or bloody/black stools. His history is significant for chronic obstructive pulmonary disease (COPD) and well-controlled hypertension. He does not drink alcohol but has a 35 pack-year smoking history. On physical exam, blood pressure is 90/60 mmHg, heart rate is 120/min, respiratory rate is 24/min, and he is afebrile. He appears to be in moderate distress secondary to pain and is diaphoretic. Lungs are clear bilaterally to auscultation without rales or rhonchi. Cardiac exam reveals a regular rhythm without murmurs, rubs, or gallops. His abdomen is moderately tender to palpation diffusely but worse in the mid-abdomen and in the left lower quadrant. He has no rebound or guarding. A palpable, tender pulsatile mass is felt in the midline just above the umbilicus. Rectal exam reveals no blood, stool, or masses. Femoral, popliteal, and pedal pulses are 1+ bilaterally. Laboratory examination reveals a hemoglobin of 10.1 g/dL (normal 12.3–15.7 g/dL), hematocrit of 30.3% (37–46%), and white blood cell count of 11 × 103/μL (4.1–10.9 × 103/μL), aminotransferase (AST) of 44 μ/L (5–35 μ/L), alanine aminotransferase (ALT) of 65 μ/L (7–56 μ/L), lipase of 50 μ/L (7–60 μ/L), and amylase of 62 μ/L (30–110 μ/L).