Background: Emphysematous gastritis is a rare, life-threatening infection of the gastric wall caused by gas-forming organisms, with reported mortality rates up to 62%. Differentiating it from benign gastric emphysema is essential, as the former often requires urgent surgical intervention. Case Presentation: We report the case of a 73-year-old female with diet-controlled diabetes mellitus and atrial fibrillation on apixaban who presented with acute post-prandial epigastric pain, nausea, and vomiting. CT imaging revealed portal venous gas, intramural gastric gas, and splenic infarction, raising concern for emphysematous gastritis with associated ischemia. She underwent urgent total gastrectomy with Roux-en-Y reconstruction, which demonstrated full-thickness gastric necrosis and splenic infarction. Postoperatively, she recovered uneventfully following multidisciplinary management, including broad-spectrum antibiotics, nutritional support, and transition from apixaban to warfarin. Conclusion: This case illustrates the diagnostic challenges of emphysematous gastritis, which may present with subtle clinical findings despite catastrophic pathology. The presence of portal venous gas and associated infarction should prompt urgent surgical evaluation. Early recognition and timely intervention can improve outcomes in this otherwise highly fatal condition.