Systematic approach to vague acute abdominal pain with prior surgeries

[DennisM]

I'm a third-year medical resident on my internal medicine rotation, and I just admitted a patient with acute, diffuse abdominal pain, nausea, and a low-grade fever. The labs are nonspecific so far, and the imaging is pending. I'm working through the abdominal pain differential diagnosis, considering everything from atypical appendicitis and diverticulitis to pancreatitis or even an early mesenteric ischemia, but the patient's history is complicated by prior abdominal surgeries. I'd appreciate any insights on systematic approaches or red flags you prioritize when the presentation is this vague initially.