缺血性肠病课件

1、缺血性肠病Ischemic ColitisRi 陳宏彰第一页，共三十页。缺血性肠病Reference bookslHarrisons online 15thlMarx: Rosens Emergency Medicine: Concepts and Clinical Practice, 5th ed., Copyright 2002 Mosby, Inc第二页，共三十页。缺血性肠病Ischemic ColitislIschemia of the colon most often affects the elderly (90% of patients 60 y/o ).lIschemic co

2、litis is almost always nonocclusive. (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.第三页，共三十页。缺血性肠病Ischemic ColitislMost patients ischemia occurs secondary to arteriolar shunting, sp

3、asm, or poor perfusion of mucosal vessels.lMost 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:

4、 Concepts and Clinical Practice, 5th ed 第四页，共三十页。缺血性肠病Types of Ischemic ColitislAcute fulminant ischemic colitis lSubacute ischemic colitis HARRISONS ONLINE 15TH 第五页，共三十页。缺血性肠病Types of Ischemic ColitisGangrenous ischemic colitis a complete loss of arterial flow causes bowel wall infarction and gangr

5、ene, which can progress to perforation, peritonitis, and death. Stricturing 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, reversib

6、le impairment of the arterial supply, which causes a partial mucosal slough that heals by mucosal regeneration in a few days. the most common Marx: Rosens Emergency Medicine: Concepts and Clinical Practice, 5th ed 第六页，共三十页。缺血性肠病Acute fulminant ischemic colitis manifestations lThe onset is characteri

7、stically acute, with generalized lower abdominal pain, usually in the left lower quadrant, followed within 24 hours by bloody diarrhea or rectal bleeding .lDilation of the colon and physical signs of peritonitis are seen in severe cases. lWith the gangrenous type, both symptoms and signs progress ra

8、pidly. 第七页，共三十页。缺血性肠病Acute fulminant ischemic colitis Diagnostic StrategylNo specific serum markers 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 coli

9、tis because of the risk of perforation )第八页，共三十页。缺血性肠病thumbprinting 第九页，共三十页。缺血性肠病Acute fulminant ischemic colitis Diagnostic StrategylSigmoidoscopy or colonoscopy may detect ulcerations, friability, and bulging folds from submucosal hemorrhage. (Colonoscopy is preferred over sigmoidoscopy )lThe seg

10、mental distribution and rectal sparing of the disease process are suggestive but are not diagnostic. 第十页，共三十页。缺血性肠病Colonoscopic view showing marked erythema and exudate in sigmoid colon 第十一页，共三十页。缺血性肠病Endoscopic view of mucosal edema, exudates, and ulcerations in sigmoid colon 第十二页，共三十页。缺血性肠病Endosco

11、pic image of descending colon showing severe colitis with pneumatosis intestinalis. 第十三页，共三十页。缺血性肠病Acute fulminant ischemic colitis Diagnostic StrategylAngiography is not helpful in the management of patients with presumed ischemic colitis because a remediable occlusive lesion is very rarely found.

12、lCT scan is normal in early stages of bowel infarction, although it may show nonspecific findings such as bowel wall thickening and pneumatosis. 第十四页，共三十页。缺血性肠病CT showing left sided colonic thickening.第十五页，共三十页。缺血性肠病Pneumatosis Intestinalis 第十六页，共三十页。缺血性肠病Pneumatosis Intestinalis 第十七页，共三十页。缺血性肠病Acut

13、e 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. 第十八页，共三十页。缺血性肠病managementlVasopressors should be avoided, if possible. l

14、Low blood-flow states (hypotension) should be aggressively reversed.第十九页，共三十页。缺血性肠病Types of Ischemic ColitislAcute fulminant ischemic colitis lSubacute ischemic colitis 第二十页，共三十页。缺血性肠病Subacute ischemic colitis manifestations lIt produces lesser degrees of pain and bleeding, often occurring over seve

15、ral days or weeks. lThe left colon may be involved, but the rectum is usually spared because of the collateral blood supply.第二十一页，共三十页。缺血性肠病Subacute ischemic colitis managementlSubacute Ischemic colitis without evidence of peritonitis or perforation is generally self-limited and requires only conser

16、vative management, including bowel rest, parenteral fluids, and antibiotics.第二十二页，共三十页。缺血性肠病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.

17、 第二十三页，共三十页。缺血性肠病Differential ConsiderationslIschemic 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. 第二十四页，共三十页。

18、缺血性肠病Differential ConsiderationslThe features considered 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 dise

19、ase therapy, 4.frequent progression to fibrotic stenosis with delayed obstructionlThe features above are now recognized as characteristic of colonic ischemia. 第二十五页，共三十页。缺血性肠病Differential ConsiderationslAlways consider the diagnosis of ischemic colitis whenever contemplating the diagnosis of inflamm

20、atory bowel disease in an elderly patient. 第二十六页，共三十页。缺血性肠病Differential DiagnosisClinical 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