Differential Diagnosis for Post-Coronary Artery Bypass Grafting Symptoms

Single Most Likely Diagnosis

• Acute pancreatitis: This condition is a known complication following cardiac surgery, including coronary artery bypass grafting (CABG). The symptoms of nausea, epigastric pain, and tenderness are classic for acute pancreatitis. The stress of surgery, potential ischemia, or medications used during and after surgery can precipitate pancreatitis.

Other Likely Diagnoses

• Perforated peptic ulcer: Although less common, stress from surgery can lead to peptic ulcer disease, and a perforation would present with severe abdominal pain and tenderness. The use of NSAIDs or steroids post-operatively can increase the risk.
• Acute cholecystitis: Inflammation of the gallbladder can occur post-surgically, especially if the patient has gallstones. Symptoms include right upper quadrant pain, which might radiate to the epigastric area, nausea, and vomiting.
• Acute myocardial infarction: While less likely to present with epigastric pain as the primary symptom, myocardial infarction can occur post-CABG due to graft occlusion or native coronary artery disease progression. Atypical presentations, including epigastric discomfort, can occur, especially in diabetic patients.

Do Not Miss Diagnoses

• Mesenteric ischemia: This is a potentially catastrophic condition that can occur post-operatively due to embolism, thrombosis, or venous thrombosis. It presents with severe abdominal pain out of proportion to physical findings, and early diagnosis is crucial for survival. The symptoms can be non-specific, including nausea and abdominal tenderness.
• Perforated viscus: Any perforation in the gastrointestinal tract can lead to severe consequences if not promptly addressed. Symptoms include severe abdominal pain and tenderness, which could initially be localized to the epigastric area.

Rare Diagnoses

• Hepatic artery thrombosis: Although rare, this can occur post-CABG and presents with right upper quadrant pain, which might be referred to the epigastric area, and elevated liver enzymes.
• Splenic infarction: This could occur due to embolic events or thrombosis post-surgically, presenting with left upper quadrant pain that might radiate to the epigastric area.

Each of these diagnoses requires careful consideration based on the patient's clinical presentation, laboratory findings, and imaging studies to ensure timely and appropriate management.