Acute and Chronic Mesenteric Ischemia Due to Superior Mesenteric Artery Embolus

Abstract

Purpose: Introduction: The clinical presentation of mesenteric ischemia is dependent on the underlying etiology, with acute mesenteric ischemia (AMI) and chronic mesenteric ischemia (CMI) presenting differently. The classic clinical picture of AMI involves severe abdominal pain with a paucity of physical examination findings in patients with cardiac risk factors. In contrast, CMI typically causes postprandial abdominal pain, weight loss and sitophobia. We describe a rare case of AMI and CMI due to superior mesenteric artery (SMA) embolus in a patient with atrial fibrillation. Case Presentation: A 63-year-old female presented with sudden onset of severe abdominal pain for 2 days. The pain was associated with nausea and vomiting. Her medical history was significant for atrial fibrillation (AF) on anticoagulation. Her vital signs were T 101.1°F, BP 158/90 mmHg, HR 109 beats/min, RR 28 breaths/min, and SpO2 97% on ambient air. Her heart sounds revealed a rapid, irregular rhythm. The abdomen was soft and mildly tender to deep palpation in the left lower quadrant. Laboratory studies were unremarkable except for a WBC of 10.900/μL with 79% neutrophils. Abdominal radiograph and CT demonstrated distended proximal loops of bowel. Subsequent selective arteriography showed an abrupt cutoff of the proximal SMA distal to the first left jejunal branch consistent with embolism. Since there were no definitive signs of bowel necrosis, she was treated conservatively, including anticoagulation with heparin/warfarin. Three months later, however, she presented with chronic left quadrant pain associated with weight loss. Abdominal CT revealed thickened loops of small bowel in the left abdomen with haziness of the associated mesentery, representing chronic ischemia from SMA embolus. With adequate analgesics and therapeutic anticoagulation, her symptoms improved. Discussion: Although AMI and CMI present differently in general, both can progress to bowel infarction rapidly if untreated. Our case is of interest in that CMI developed after AMI and was managed without surgical intervention. Treatment of mesenteric ischemia is dependent upon the type and degree of ischemia, but any patient with peritoneal signs should be operated without delay. Patients with minor emboli, limited to SMA branches or to the SMA distal to ileocolic artery, as was shown in our case, may be managed conservatively with volume resuscitation and anticoagulants. Mesenteric ischemia is a relatively uncommon cause of abdominal pain, but one with a high mortality rate. Its prompt recognition and aggressive treatment can prevent bowel infarction. Therefore, in the proper clinical settings, it is crucial to maintain a high index of suspicion.