Non-occlusive colonic ischemia induced by verapamil ER overdose

Abstract

Sir: Verapamil overdose can cause conduction disturbances and hypotension with cardiogenic shock [1], both of which can lead to ischemia. The colon is susceptible to ischemia because of the variable amount of collateral blood flow present, especially in arteriosclerotic patients [2, 3]. We report a case of colonic ischemia after verapamil overdose. A 60-year-old man with a history of hypertension, arteriosclerosis, aortofemoral bypass (with clamping of inferior mesenteric artery) 2 years ago and tobacco addiction was being treated with clopidogrel 75 mg/day and verapamil ER 240 mg/day. He came to the emergency department intoxicated after taking approximately 30 verapamil extended-release tablets and three clopidogrel tablets as a suicide attempt. His blood pressure was 72/38 mmHg, and his pulse rate was 52 beats/min. He was drowsy and had thready peripheral pulses. An electrocardiogram showed an atrioventricular block. A bottle of activated charcoal (50 g) was given and could be ingested by the patient. Despite the administration of intravenous fluids, calcium gluconate, and vasopressors, the patient’s blood pressure only marginally improved. He subsequently developed lower abdominal pain. Repeated examination showed abdominal distension with lower-quadrant guarding and absent bowel sounds. His leukocyte count was 22,000 cells/mm, and tomodensitometry of the abdomen showed a peritoneal effusion, a defect of opacification of the left colon with respect to opacification of celiac and superior mesenteric arteries (Fig. 1a, b). An exploratory laparotomy showed a gangrenous segment of the left colon; the rest of the colon and ileum was normal. He had a left hemicolectomy with a colostomy. Histolopathological evaluation showed a pronounced edema of the submucosa with the dilation of the submucosal vessels and several areas with necrotic ulcerations and intramural bleeding (Fig. 1c, d). There was no evidence of thromboembolic obstruction. He was hemodynamically stable during the remainder of his hospitalization and developed immediately acute respiratory distress syndrome. Finally, he left the ICU at day 30. Long-term verapamil use has also been reported as a cause of stercoral perforation of the sigmoid colon [4]. A previous case of caecal and