S4053 Atypical Presentation of Ischemic Colitis in a Previously Healthy 75-Year-Old Woman

Introduction: Ischemic colitis (IC) typically occurs in older adults with cardiovascular risk factors such as atherosclerosis, atrial fibrillation (AF), or hypotension. However, its development in a previously healthy, medication-free 75-year-old woman following a minor head trauma is unusual. This case highlights the importance of recognizing ischemic colitis in atypical presentations and its potential for rapid deterioration. Case Description/Methods: A 75-year-old woman with no significant medical history presented to the Emergency Department after a mechanical fall, striking the side of her head. She reported nausea and headache but had no loss of consciousness. Computed tomography (CT) imaging was negative for fractures or acute pathology. She was diagnosed with a concussion and discharged home. She returned the next day with nausea, vomiting, epigastric pain, and bright red blood per rectum. New-onset atrial fibrillation (AF) with rapid ventricular response (RVR) was noted, along with a lactate level of 9 mmol/L, raising concern for mesenteric ischemia. CT angiogram showed ischemic colitis affecting the descending and sigmoid colon. She was started on intravenous (IV) fluids, broad-spectrum antibiotics (piperacillin-tazobactam, vancomycin), IV diltiazem for AF, and a heparin drip. On hospital day 2, she developed lethargy, hypoxia, and hypotension, requiring ICU transfer. ABG showed severe metabolic acidosis (pH 7.15), and echocardiography revealed a newly reduced ejection fraction (34%). She tested positive for Influenza A. Sigmoidoscopy confirmed ischemic colitis, and due to worsening lactic acidosis and bowel ischemia, she was taken for emergency laparotomy. Discussion: This case is unique due to the absence of traditional risk factors and the rapid systemic decline following a seemingly minor event. The new-onset AF with RVR likely contributed to mesenteric ischemia. Additionally, Influenza A may have played a role by inducing systemic stress, dehydration, or hypercoagulability. This case underscores the importance of early recognition and intervention in ischemic colitis, even in atypical scenarios.