When Tachycardia Tells Two Stories: The Diagnostic Dilemma of Concurrent Upper Gastrointestinal Hemorrhage and Alcohol Withdrawal Syndrome in a Post-Coronary Artery Bypass Graft Patient.

Acute upper gastrointestinal bleeding (UGIB) and alcohol withdrawal syndrome (AWS) are two of the most common medical emergencies encountered in the intensive care unit (ICU). Both conditions share tachycardia as a cardinal sign, yet the clinical implications are diametrically opposed: in UGIB, tachycardia signals hemorrhagic hypovolemia requiring volume resuscitation, while in AWS, tachycardia reflects sympathetic hyperactivity requiring sedation. We present the case of a 57-year-old man with a history of triple coronary artery bypass grafting (CABG) and peptic ulcer disease who presented with hematemesis while on low-dose aspirin without gastroprotective therapy. Esophagogastroduodenoscopy revealed diffuse erythematous gastritis with patchy erosive mucosal changes without active bleeding or varices. Hours after ICU admission, the patient developed tachycardia and tremors, raising the critical question of whether these signs represented rebleeding, emerging alcohol withdrawal, or both. The Clinical Institute Withdrawal Assessment for Alcohol-Revised (CIWA-Ar) scale, the most widely used tool for monitoring AWS, is not validated in patients with concurrent acute medical illness, and its scores can be confounded by coexisting conditions. This case highlights the limitations of standard assessment tools when two life-threatening conditions share overlapping clinical features and proposes a clinical framework for differentiating hemorrhagic tachycardia from withdrawal tachycardia at the bedside. Longitudinal review of the patient's medical records revealed a 15-year progression from denied alcohol use to physiologic dependence, underscoring the importance of serial screening for alcohol use disorder.