Mesenteric Ischemia

Mesenteric ischemia is a VASCULAR EMERGENCY with HIGH MORTALITY (50-80%). For Zambian students, it is a DIAGNOSTIC CHALLENGE, often missed. CLASSIFICATION: ACUTE MESENTERIC ISCHEMIA (AMI): superior mesenteric artery (SMA) embolism (50%), SMA thrombosis (20-30%), mesenteric venous thrombosis (MVT, 10-15%), non-occlusive mesenteric ischemia (NOMI, 20%). CHRONIC MESENTERIC ISCHEMIA (CMI): 'intestinal angina'. CLINICAL: AMI: SUDDEN, SEVERE ABDOMINAL PAIN 'OUT OF PROPORTION TO EXAMINATION'. Early: pain, minimal tenderness. Late: peritonitis (bowel infarction), bloody diarrhoea, vomiting, shock. Atrial fibrillation (embolism), atherosclerosis (thrombosis), hypercoagulable state (MVT). NOMI: ICU, vasopressors, dialysis. CMI: POSTPRANDIAL ABDOMINAL PAIN (15-30 minutes after meals), FEAR OF EATING (sitophobia), WEIGHT LOSS, abdominal bruit. DIAGNOSIS: HIGH INDEX OF SUSPICION. LABS: LACTATE (elevated, LATE marker), leukocytosis, metabolic acidosis. CT ANGIOGRAPHY (CECT, arterial and venous phases): GOLD STANDARD. Findings: SMA occlusion/filling defect, pneumatosis intestinalis, portal venous gas, bowel wall thinning/thickening, pneumoperitoneum. MVT: thrombus in SMV/portal vein, bowel wall thickening. CMI: stenosis/occlusion of mesenteric vessels, collaterals. PLAIN X-RAY: non-specific, ileus, thumbprinting (late). MANAGEMENT: AMI: RESUSCITATION (IV fluids, correct electrolytes). BROAD-SPECTRUM ANTIBIOTICS (cover gut flora). SYSTEMIC ANTICOAGULATION (heparin). REVASCULARIZATION: EMBOLECTOMY, THROMBECTOMY, BYPASS, ANGIOPLASTY/STENTING. URGENT LAPAROTOMY: resection of non-viable bowel, second-look laparotomy (24-48h). MVT: ANTICOAGULATION (heparin → warfarin) x 3-6 months (indefinite if thrombophilia). NOMI: treat underlying cause, intra-arterial vasodilators (papaverine). CMI: REVASCULARIZATION (angioplasty/stenting, bypass). Prognosis: AMI: MORTALITY 50-80%. Delayed diagnosis = death. CMI: good with revascularization. Zambian context: AMI IS UNDERDIAGNOSED. Suspect in: elderly, AF, severe abdominal pain, lactate elevated. CT ANGIOGRAPHY: available tertiary, limited. SURGERY: laparotomy, bowel resection available. ANTICOAGULATION: heparin, warfarin available. VASCULAR SURGERY/INTERVENTIONAL RADIOLOGY (embolectomy, stenting): LIMITED. HIGH MORTALITY. FOCUS: HIGH INDEX OF SUSPICION, EARLY CT ANGIOGRAPHY, AGGRESSIVE RESUSCITATION, ANTIBIOTICS, ANTICOAGULATION (MVT, embolism), URGENT SURGICAL CONSULTATION (laparotomy, resection).