gastrointestinal disorders
Acute Mesenteric Ischemia
Etiology of Acute Mesenteric Ischemia
Three major vessels serve the abdominal contents: Celiac trunk: Supplies the esophagus, stomach, proximal duodenum, liver, gallbladder, pancreas, and spleen Superior mesenteric artery (SMA): Supplies the distal duodenum, jejunum, ileum, and colon to the splenic flexure Inferior mesenteric artery (IMA): Supplies the descending colon, sigmoid colon, and rectum Collateral vessels are abundant in the stomach, duodenum, and rectum; these areas rarely develop ischemia. The splenic flexure is a watershed between the SMA and IMA and is at particular risk of ischemia. Note that acute mesenteric ischemia is distinct from Ischemic Colitis , which involves only small vessels and causes mainly mucosal necrosis and bleeding. Mesenteric blood flow may be disrupted on either the venous or arterial sides. In general, patients>50 are at greatest risk and have the types of occlusions and risk factors shown in table. However, many patients have no identifiable risk factors. 