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1、Ischemic ColitisRi 陳宏彰Reference bookslHarrisons online 15thlMarx: Rosens Emergency Medicine: Concepts and Clinical Practice, 5th ed., Copyright 2002 Mosby, IncIschemic ColitislIschemia of the colon most often affects the elderly (90% of patients 60 y/o ).lIschemic colitis is almost always nonocclusi
2、ve. (emboli are the most common cause of acute mesenteric ischemia)lShunting of blood away from the mucosa may contribute to this condition, but the mechanism is unknown.Ischemic ColitislMost patients ischemia occurs secondary to arteriolar shunting, spasm, or poor perfusion of mucosal vessels.lMost
3、 cases involve the splenic flexure, which is supplied by end-arteries. lThe rectum is usually spared, because its blood supply is different from the rest of the colon and less dependent on the inferior mesenteric artery .Marx: Rosens Emergency Medicine: Concepts and Clinical Practice, 5th ed Types o
4、f Ischemic Colitis1.Acute fulminant ischemic colitis 2.Subacute ischemic colitis HARRISONS ONLINE 15TH Types of Ischemic ColitisGangrenous ischemic colitis a complete loss of arterial flow causes bowel wall infarction and gangrene, which can progress to perforation, peritonitis, and death. Stricturi
5、ng ischemic colitis a gross impairment of the arterial supply, leading to hemorrhagic infarction of the mucosa, which ulcerates, heals by fibrosis, and finally leads to stenosis. Transient ischemic colitis a transient, reversible impairment of the arterial supply, which causes a partial mucosal slou
6、gh that heals by mucosal regeneration in a few days. the most common Marx: Rosens Emergency Medicine: Concepts and Clinical Practice, 5th ed Acute fulminant ischemic colitis manifestations 1.The onset is characteristically acute, with generalized lower abdominal pain, usually in the left lower quadr
7、ant, followed within 24 hours by bloody diarrhea or rectal bleeding .2.Dilation of the colon and physical signs of peritonitis are seen in severe cases. 3.With the gangrenous type, both symptoms and signs progress rapidly. Acute fulminant ischemic colitis Diagnostic StrategylNo specific serum marker
8、s proven in the diagnosis of intestinal ischemia. lAbdominal films may reveal thumbprinting from submucosal hemorrhage and edema . * (barium enema is contraindicated in cases of gangrenous ischemic colitis because of the risk of perforation )thumbprintingAcute fulminant ischemic colitis Diagnostic S
9、trategylSigmoidoscopy or colonoscopy may detect ulcerations, friability, and bulging folds from submucosal hemorrhage. (Colonoscopy is preferred over sigmoidoscopy )lThe segmental distribution and rectal sparing of the disease process are suggestive but are not diagnostic. Colonoscopic view showing
10、marked erythema and exudate in sigmoid colon Endoscopic view of mucosal edema, exudates, and ulcerations in sigmoid colon Endoscopic image of descending colon showing severe colitis with pneumatosis intestinalis. Acute fulminant ischemic colitis Diagnostic StrategylAngiography is not helpful in the
11、management of patients with presumed ischemic colitis because a remediable occlusive lesion is very rarely found. lCT scan is normal in early stages of bowel infarction, although it may show nonspecific findings such as bowel wall thickening and pneumatosis. CT showing left sided colonic thickening.
12、Pneumatosis Intestinalis Pneumatosis Intestinalis Acute fulminant ischemic colitis managementlWhen ischemic colitis is suspected, a surgeon should be consulted. lGangrenous ischemic colitis or evidence of perforation requires immediate surgery as soon as the patient is stabilized. managementlVasopre
13、ssors should be avoided, if possible. lLow blood-flow states (hypotension) should be aggressively reversed.Types of Ischemic Colitis1.Acute fulminant ischemic colitis 2.Subacute ischemic colitis Subacute ischemic colitis manifestations lIt produces lesser degrees of pain and bleeding, often occurrin
14、g over several days or weeks. lThe left colon may be involved, but the rectum is usually spared because of the collateral blood supply.Subacute ischemic colitis managementlSubacute Ischemic colitis without evidence of peritonitis or perforation is generally self-limited and requires only conservativ
15、e management, including bowel rest, parenteral fluids, and antibiotics.Subacute ischemic colitis management lMost cases of nonocclusive ischemic colitis resolve in 2 to 4 weeks and do not recur. lSurgery is not required except for obstruction secondary to postischemic stricture. Differential Conside
16、rationslIschemic colitis often mimics infectious colitis, inflammatory bowel disease, or even colon carcinoma. lMany cases of colitis in the elderly once considered to be Crohns disease or ulcerative colitis in retrospect were really colonic ischemia. Differential ConsiderationslThe features conside
17、red atypical in inflammatory bowel diseases , such as 1.segmental distribution of the disease, infrequent rectal involvement, 2.high rate of spontaneous recovery, low rate of recurrence, 3.lack of adequate response to usual inflammatory bowel disease therapy, 4.frequent progression to fibrotic steno
18、sis with delayed obstructionlThe features above are now recognized as characteristic of colonic ischemia. Differential ConsiderationslAlways consider the diagnosis of ischemic colitis whenever contemplating the diagnosis of inflammatory bowel disease in an elderly patient. Differential DiagnosisClin
19、ical Radiologic Ulcerative colitis Bloody diarrhea Extends proximally from rectum; fine mucosal ulceration Crohns colitis Perianal lesions common; frank bleeding less frequent than in ulcerative colitisSegmental disease; rectal sparing; strictures, fissures, ulcers, fistulas; small bowel involvement
20、 Ischemic colitis Older age groups; vascular disease; sudden onset, often painful Splenic flexure; “thumb printing”; rectal involvement rare ConclusionslAlways consider the diagnosis of ischemic colitis whenever contemplating the diagnosis of inflammatory bowel disease in the elderly. lThumbprinting of the colon on plain abdominal radiographs suggests ischemic colitis. lSurgical consultation is warranted in all cases of suspected ischemic colitis. Thanx for your attention
