Differential Diagnosis for Post-CABG Nausea, Epigastric Pain, and Tenderness

• Single Most Likely Diagnosis
  • Acute pancreatitis (post-operative hypoperfusion): This condition is a plausible cause of nausea, epigastric pain, and tenderness following CABG, especially considering the potential for hypoperfusion during the surgical procedure.
• Other Likely Diagnoses
  • Perforated peptic ulcer: Although less common in the immediate post-operative period without a clear history of ulcer disease, it remains a possible cause of acute abdominal symptoms.
  • Acute myocardial infarction: While less directly related to epigastric pain and tenderness, myocardial infarction can present atypically, especially in post-surgical patients, and should be considered due to the recent cardiac surgery.
• Do Not Miss Diagnoses
  • Acute mesenteric ischemia: This is a potentially lethal condition that could present with abdominal pain and nausea. Given the recent CABG and potential for embolic events or hypoperfusion, it's crucial not to miss this diagnosis.
  • Gastrointestinal bleeding: Although not directly implied by the symptoms, gastrointestinal bleeding could lead to nausea and abdominal discomfort and is a critical condition to identify promptly.
• Rare Diagnoses
  • Cholecystitis: While possible, cholecystitis is less likely in the immediate post-operative period without specific risk factors or symptoms suggestive of gallbladder disease.
  • Diabetic ketoacidosis (if the patient is diabetic): This could present with abdominal pain and nausea but would typically be accompanied by other symptoms such as hyperglycemia and metabolic acidosis.

Each of these diagnoses should be considered in the context of the patient's overall clinical picture, including laboratory results, physical examination findings, and the specifics of their surgical procedure and post-operative course.