A 66-year-old man with atrial fibrillation suddenly develops severe generalised abdominal pain. Examination shows a soft abdomen with pain far out of proportion to minimal tenderness; bowel sounds are present. Serum lactate is 1.6 mmol/L and WBC is mildly raised. What is the most likely diagnosis?

• A Perforated peptic ulcer
• B Acute pancreatitis
• C Superior mesenteric artery embolism ✓
• D Strangulated adhesive small bowel obstruction

Explanation

Severe pain out of proportion to physical signs in a patient with a cardiac source of emboli is the classic presentation of superior mesenteric artery embolism. Lactate rises late, once transmural infarction has occurred, so a normal early lactate does not exclude the diagnosis and should never delay CT angiography. Strangulated obstruction would show distension, obstructive symptoms, and guarding earlier in the course.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.