Acute Mesenteric Ischemia

Key considerations: SMA embolism (most common — atrial fibrillation source), SMA thrombosis, Non-occlusive mesenteric ischemia (NOMI)

Cannot miss

history: Abdominal pain character and onset, atrial fibrillation, atherosclerotic disease, hypercoagulable state, food fear/weight loss; exam: Abdominal exam (often benign early despite severe pain), peritoneal signs (late), rectal exam (occult blood); labs: Lactate (elevated suggests ischemia/necrosis — but normal does not rule out early disease), CBC, BMP, coags, type and screen, ABG; imaging: CT angiography abdomen/pelvis with contrast (test of choice); Plain films may show pneumatosis intestinalis (late finding); bedside: Serial abdominal exams, hemodynamic monitoring

immediate: NPO immediately, IV fluids, anticoagulation (heparin bolus and drip); Urgent surgical and IR consult; general: Avoid vasoconstrictors, broad-spectrum antibiotics if peritoneal signs; Emergent OR if signs of necrosis; IR thrombectomy/thrombolysis if no peritoneal signs; ICU admission for all

admit: All — surgical or IR suite urgently, ICU level care; discharge: Never acutely; consults: Vascular/general surgery emergently, interventional radiology, GI

Normal lactate does NOT rule out early mesenteric ischemia — CT angiography is the definitive test
Pain out of proportion to exam is the hallmark — a soft belly with excruciating pain = mesenteric ischemia until proven otherwise
Mortality exceeds 60% if diagnosis delayed beyond 24 hours