Intestinal Ischemia Acute Mesenteric Ischemia Arterial base occlusion Regional emergency If not reversed, pt dies SBO prox colon, ascending colon, sigmoid colon Ischemia - acute pain out of proportion to physical exam findings No rigidity, guarding, rebound tenderness Classic signs of peritoneal irritation only when have perforated Venous occlusion More common Portal HTN Backflow of blood Partial occlusion Less severe Complete occlusion Shock Chronic Mesenteric Ischemia Atherosclerotic changes Blood flow reduced to intestine Classic LLQ pain Postprandial Weight loss More common in women Usually asymptomatic Ischemic Colitis Bright red blood in stools Usually hypertensive The one vasodilator that doesn't constrict a single vessel (isosorbide mononitrate) Watershed area ACUTE MESENTRIC ISCHEMIA Regardless of cause ↑ anaerobic glycolysis → lactic acid ↑ lactate in blood ischemia if not reversed in an appropriate amount of time cellular hypoxia ↓ cellular resp. → necrosis + infarct weakening of bowel wall any intralumen pressure → tissue destruction perforation → may lead to peritonitis air leaks into peritoneum X-ray finding: pneumoperitoneum 02 ↓ → lactic acid ↑ PRR labs - ↑ metabolic acidosis loss of mucosal integrity bowel no longer absorbs bacterial translocation sepsis, blue hue inflammation + infection intense abdominal pain rigidity, guarding rebound tenderness may progress to septic shock can easily, quickly die sits under diaphragm sepsis pneumoperitoneum af systemic inflammation angiogram