S3681 Acute Ischemic Colitis as an Initial Complication of Newly Diagnosed Atrial Flutter: A Case Report

Introduction: Ischemic colitis (IC), the most common form of gastrointestinal (GI) ischemia, typically arises from transient reductions in mesenteric perfusion. It is associated with risk factors such as diabetes, cardiac disease, and systemic hypotension. While atrial fibrillation has been linked to ischemic colitis, there are no well-documented cases directly connecting atrial flutter to this condition. We present a unique case of acute ischemic colitis occurring in the setting of newly diagnosed atrial flutter, emphasizing the importance of suspecting and recognizing GI ischemia in patients with new-onset arrhythmias and hemodynamic changes. Case Description/Methods: A 60-year-old woman with a history of diabetes mellitus, schizophrenia, and bipolar disorder presented with a 1 year history of recurrent dizziness episodes, frequent falls and a 2-month history of loose stool with 40-pound weight loss. In the Emergency Department, the EKG showed a pattern of atrial flutter with a slow ventricular rate (57 bpm) despite no previous history of abnormal arrhythmias or heart failure. The hospital course was notable for fluctuating tachy-brady heart rate together with low blood pressure at 77/40 mmHg. Stool studies done for chronic diarrhea workup were unremarkable. Computed tomography abdomen/pelvis revealed perianal fullness associated with adjacent stranding and right ischio-rectal lymph node. Colonoscopy revealed a continuous area of moderate-to-severe friable circumferential mucosa with contact bleeding and ulceration in the recto-sigmoid colon. The tissue biopsy revealed colonic mucosa with ulceration and fibrinopurulent exudate with granulation tissue. Gram stains for bacterial, fungal infection, and CMV immunotoxins were negative. Adequate hydration and avoidance of hypotension episodes were advised. A sucralfate enema was recommended once daily for 1 month with a follow up colonoscopy upon discharge. Discussion: Arrhythmia-induced hemodynamic compromise represents a plausible mechanism for reduced mesenteric perfusion and subsequent colonic injury. Atrial flutter, like atrial fibrillation, predisposes patients to the formation of atrial thrombi that can embolize to the systemic circulation, including mesenteric arteries, leading to ischemic colitis. This case highlights the significance of considering ischemic colitis in the differential diagnosis of diarrhea, particularly in older adults or those with risk factors for hypoperfusion even when the presentation is subacute or lacks overt rectal bleeding.