Idiopathic acute mesenteric venous thrombosis causing ischemic enteritis: A case report

INTRODUCTION: Though mesenteric venous thrombosis (MVT) causes bowel ischemia far less frequently than arterial thrombosis, it still has the potential to cause life-threatening bowel infarction. PRESENTATION OF CASE: Presented here is a case of idiopathic MVT of the superior mesenteric vein and multiple distal venous branches causing diffuse peritonitis secondary to small bowel infarction in a 64 year old male. History and physical exam demonstrated severe persistent abdominal pain, hematochezia, and diffuse abdominal tenderness to palpation with guarding. Venous filling defects and segmental enteritis were noted on CT. The patient was treated with immediate IV heparin therapy with subsequent laparotomy and excision of 45 cm of ischemic ileum. The patient had an uncomplicated recovery. Post-operative thrombophilia screen was negative. The patient was discharged on indefinite warfarin therapy. DISCUSSION: MVT is often idiopathic in nature, with up to 49% having no identifiable cause. Risk factors include abdominal inflammation and systemic thrombophilias. Importantly, bowel infarction is more common with occlusion of more distal, smaller caliber mesenteric vessels. The standard of diagnosis is contrast-enhanced abdominal CT, and management is prompt anticoagulation with surgical intervention if severe. If the cause remains unclear, outpatient anticoagulation is continued indefinitely. CONCLUSION: This case provides a valuable demonstration of several important MVT concepts – specifically the high rate of idiopathic etiology, the need for indefinite anticoagulation in idiopathic cases, and the increased risk of infarction in occlusion of smaller, more distal mesenteric veins.