ischemic colitis

1. Ischemic Colitis Marcelyn Coley Team IV Surgery Conference Mount Sinai Hospital

2. May take outMay take out

3. Colonic ischemia After aortic or cardiac bypass surgery Certain systemic conditions vasculitides (eg, systemic lupus erythematosis, periarteritis nodosum) infections (eg, cytomegalovirus, E. coli O157:H7) coagulopathies (eg, protein C and S deficiencies, anti-thrombin III deficiency, APC resistance) Medications (eg, oral contraceptives) or illicit drugs (eg, cocaine) After strenuous and prolonged physical exertion (eg, long-distance running) After any major cardiovascular episode accompanied by hypotension With).

4. Ischemic Colitis COLONIC ISCHEMIA Most frequent form of mesenteric ischemia Commonly left colon Mostly elderly population Etiology Low-flow state (hypotension) Embolus (A-fib) Post MI (hypotension, mural thrombus) Post AAA reconstruction Closed loop construction - left side with intact ileocecal valve Volvulus Mesenteric Vein Thrombosis Catastrophic if not recognized Ischemic colitisIschemic colitis

5. Ischemic Colitis Incidence: Thought to be underestimated because many mild cases may go unreported. In contrast, the incidence in patients undergoing abdominal aortic reconstructive procedures has been studied. Hunter and Guernsey (1988) reported that as many as 10% of such patients have some degree of ischemic colitis.

6. Vascular Supply of the Colon SMA 1 cm below celiac axis IMA 3cm above aortic bifurcationSMA 1 cm below celiac axis IMA 3cm above aortic bifurcation

7. Ischemic Colitis: Vascular Supply Superior mesenteric artery (SMA) Ileocolic artery – terminal ileum, cecum, appendix, prox ascending colon Right colic artery – ascending colon, hepatic flexure Middle colic artery – transverse colon Inferior mesenteric artery (IMA) Left colic artery – descending, transverse colon, splenic flexure Sigmoid arteries – sigmoid and descending colon Superior rectal artery – proximal rectum Collateral flow Marginal artery of Drummond – collateral connection between SMA and IMA along the mesenteric border IMA and internal iliac – supply good collaterals to the rectum

8. Ischemic Colitis Watershed areas Splenic flexure Rectosigmoid junction Most vulnerable during systemic hypotension Narrow terminal branches of the SMA and IMA supply the splenic flexure and rectosigmoid junction, respectivelyNarrow terminal branches of the SMA and IMA supply the splenic flexure and rectosigmoid junction, respectively

9. Ischemic Colitis: Location of ischemia by regions Other areas refer to combination of different regions.Data from: Reinus, JF, Brandt, LJ, Boley, SJ, Gastroenterol Clin North Am 1990; 19:319 Left colon with descending and sigmoid colon with highest frequency Old slide, perhaps includes different etiology and doesn’t make since- 1. splenic flexure 2. cecumLeft colon with descending and sigmoid colon with highest frequency Old slide, perhaps includes different etiology and doesn’t make since- 1. splenic flexure 2. cecum

10. Ischemic Colitis Venous drainage Veins parallel their corresponding arteries SMV – drains small intestine, cecum, ascending, and transverse colon IMV – drains descending colon, sigmoid colon Superior rectal vein – rectum IMV fuses with splenic vein

11. Ischemic Colitis Pathophysiology Colonic ischemia usually result of a sudden and usually temporary reduction in blood flow insufficient to meet metabolic demands of discrete regions of the colon Occlusion Thrombus, embolus, atherosclerotic stenosis Hypoperfusion (Low-flow state) GI bleeding, hypotension, Nonocclusive mesenteric ischemia (NOMI) Mesenteric venous thrombosis Distal small bowel and prox colon

12. Ischemic Colitis Aortoiliac surgery 1% to 7% develop colonic ischemia Cardiopulmonary bypass Post-Myocardial infarction Hypotension, mural thrombus Obstruction or potentially obstructing lesions of the colon (carcinoma, diverticulitis, volvulus) Hemodialysis Typically nonocclusive due to underlying atherosclerosis, diabetes, and hemodialysis-induced hypotension Vasculitides (systemic lupus erythematosis, periarteritis nodosum) Drugs (digoxin, tegaserod, alosetron, cocaine) Extreme exericise Acquired and hereditary thrombotic conditions Antiphospholipid antibodies, Factor V Leiden mutations, Protein C and S deficiency, Antithrombin III deficiency

13. Ischemic Colitis Colon receives less blood supply compared to the rest of the gi tract thus is vulnerable to hypoperfusion Vasospasm – a mechanism to redirect blood to cerebral circulation during hypotension

14. Ischemic Colitis Mechanism of Injury Hypoxia causes detectable injury to superficial mucosa within one hour Prolonged severe ischemia – necrosis of villous layer Leads to transmural infarction in 8 to 16 hrs Reperfusion injury – mediated by release of oxygen free radicals and neutrophil activation

15. Ischemic Colitis Clinical Manifestations Acute setting Rapid mild onset abdominal pain and tenderness over affected bowel (lower abdominal) Mild to moderate rectal bleeding or bloody diarrhea VariesVaries

16. Ischemic Colitis Presenting of symptoms 95% with abdominal pain 44% with nausea 35% with vomiting 35% with diarrhea 16% presented with blood per rectum

17. Ischemic Colitis Risk factors 78% - hypertension 71% - tobacco use 62% - peripheral vascular disease 50% - coronary artery disease ACSACS

18. Ischemic Colitis Clinical Manifestations Thrombotic/embolic mesenteric occlusion present with sudden-onset severe mid-abdominal pain that is out of proportion to the physical findings typically have a history of chronic postprandial abdominal pain and significant weight loss. NOMI pain usually not as sudden as that noted with embolic or thrombotic occlusion: it is generally more diffuse and tends to wax and wane unlike the pain associated with occlusive disease, which tends to get progressively worse

19. Pain out of proportion to physical findingsPain out of proportion to physical findings

20. Ischemic Colitis Clinical stages Hyperactive phase Soon after initiating event, severe pain with frequent bloody, loose stools Paralytic phase Pain diminishes, more continuous, and diffuse Abdomen more distended, tender, without BS Shock phase (10 to 20%) Massive fluid, protein, and electrolyte leakage through gangrenous mucosa Severe, shock and metabolic acidosis, may develop Rapid surgical intervention required

21. Ischemic Colitis Diagnosis Largely based on clinical setting Physical exam Laboratory Stool cultures for suspected infectious cause Increase serum lactate, LDH, CPK, or amylase Metabolic acidosis Elevated white count >20,000 Angiography limitations – not always readily available; these patients frequently suffer from chronic diseases, i.e. cardiac/renal failure making contrast injection potentially more dangerous. In addition are frequently dehydrated and acidotic Laparoscopy limitation – concern about the effect of pneumoperitoneum on mesenteric blood flow. Prudent that intraperitoneal pressure not exceed 10 to 15mmHg in suspected mesenteric ischemia.Angiography limitations – not always readily available; these patients frequently suffer from chronic diseases, i.e. cardiac/renal failure making contrast injection potentially more dangerous. In addition are frequently dehydrated and acidotic Laparoscopy limitation – concern about the effect of pneumoperitoneum on mesenteric blood flow. Prudent that intraperitoneal pressure not exceed 10 to 15mmHg in suspected mesenteric ischemia.

22. Ischemic Colitis Radiological imaging/Endoscopic studies Plain abdominal x-ray Contrast studies Computed Tomography May be normal initially Thickening of bowel wall in segmental pattern and mesenteric stranding Pneumatosis and gas in mesenteric veins in advanced stages Endoscopy

23. Ischemic Colitis One study showed to patients with normal x-ray appeared to have a lower mortality compared to those with abnormal findings 29vs78% - PneumatosisOne study showed to patients with normal x-ray appeared to have a lower mortality compared to those with abnormal findings 29vs78% - Pneumatosis

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25. Ischemic Colitis Colonoscopy no evidence of peritonitis or perforation Preferred to contrast enemas, more sensitive in detecting mucosal lesions Segmental distribution, abrupt transition between injured and non injured mucosa, rectal sparing, and rapid resolution on serial endoscopy “single-stripe sign” – linear ulcer along longitudinal axis Biopsies may show non-specific changes (mimicking Crohn’s disease)

26. Ischemic Colitis Contrast studies Thumbprinting most suggestive on double contrast study seen early in disease In a small series of patients with mucosal ischemia 75% +thumbprinting, 60% longitudinal ulcers (source) Erect radiograph obtained after a double-contrast barium enema study shows a stricture at the splenic flexure Double-contrast barium enema study shows a stricture of the proximal descending colon secondary to ischemia Erect radiograph obtained after a double-contrast barium enema study shows a stricture at the splenic flexure Double-contrast barium enema study shows a stricture of the proximal descending colon secondary to ischemia

27. Ischemic Colitis Invasive studies – angiography, laparoscopy (dx unclear or means to follow patient postoperatively) Angiography (rarely helpful) Laparoscopy Particularly in elderly with comorbid disease and may not tolerate laparotomy “Second-look” to assess viability of remaining bowel Only serosal gut visualization, which may appear normal in early stages; progressive phase, dark peritoneal fluid, edematous bowel, or patchy hemorrhages, frank gangrene, or perforation may be present Magnetic Resonance Angiography, Duplex sonography – hardly ever required for colonic ischemia

28. Ischemic Colitis Differential Diagnosis Infectious colitis C. difficile, parasitic Inflammatory bowel disease Diverticulitis Radiation enteritis Solitary rectal ulcer syndrome Colon carcinoma Based on symptomsBased on symptoms

29. Ischemic Colitis Management Nonocclusive ischemia Supportive IVF, bowel rest, empiric antibiotics (mod to severe cases) NGT (ileus) Hold meds that can promote ischemia Optimize cardiac and pulmonary function Laparotomy with resection Clinical deterioration despite conservative therapy

30. Think about taking out Think about taking out

31. Ischemic Colitis Colonic infarction Requires urgent surgical intervention Bowel prep should not be given prior to surgery Right-sided ischemia/necrosis Right hemicolectomy with primary anastamosis If perforation associated with peritonitis, resection with terminal ileostomy mucocutaneous fistula Left-sided involvement Proximal stoma and distal mucous fistula or Hartmann’s procedure Ostomy closure delayed 4 to 6 months Fulminating type (rare) Total colectomy with end-ileostomy Many advocate a 2nd look with 12 to 24 h to document viability Mortality following large bowel infarction as high a 50 to 75%

32. Prognosis Most patients with non-occlusive ischemia improve within 1 or 2 days A minority develop long-term complications Segmental colitis or stricture ~15% develop severe gangrene 5-yr survival 70-86% those that survive surgical revascularization Take out or leave with referenceTake out or leave with reference

33. No randomized controlled trials Improved Outcome bv Identification of High-Risk Nonocclusive Mesenteric Ischemia, Aggressive Reexploration, and Delayed Anastomosis David Ward, MD et al. St. Louis, Missouri. Am J Surg. 1995 170:577-581 34 patients with NOMI Retrospective study over 7years Concluded that improved survival depended on identification of high-risk groups, aggressive re-exploration, and delayed intestinal anastamosis

34. Ischemic Colitis Summary Most frequent form of Mesenteric Ischemia Spectrum of conditions and predisposing factors Early recognition and aggressive treatment essential to survival Christiansen, MG, Lorentzen, JE, Schroeder, TV. Revascularization of atherosclerotic mesenteric arteries: Experience in 90 consecutive patients. Eur J Vasc Surg 1994; 8:297. Cunningham, CG, Reilly, LM, Rapp, JH, et al. Chronic visceral ischemia: Three decades of progress. Ann Surg 1991; 214:276. McCollum, CH, Graham, JM, DeBakey, ME. Chronic mesenteric vascular insufficiency: Results of revascularization in 33 cases. South Med J 1976; 69:1266. Kieny, R, Batellier, J, Kretz, JG. Aortic reimplantation of the superior mesenteric artery for atherosclerotic lesions of the visceral arteries: Sixty cases. Ann Vasc Surg 1990; 4:122.Christiansen, MG, Lorentzen, JE, Schroeder, TV. Revascularization of atherosclerotic mesenteric arteries: Experience in 90 consecutive patients. Eur J Vasc Surg 1994; 8:297. Cunningham, CG, Reilly, LM, Rapp, JH, et al. Chronic visceral ischemia: Three decades of progress. Ann Surg 1991; 214:276. McCollum, CH, Graham, JM, DeBakey, ME. Chronic mesenteric vascular insufficiency: Results of revascularization in 33 cases. South Med J 1976; 69:1266. Kieny, R, Batellier, J, Kretz, JG. Aortic reimplantation of the superior mesenteric artery for atherosclerotic lesions of the visceral arteries: Sixty cases. Ann Vasc Surg 1990; 4:122.