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Combined 05 clinical training--pathology benign_ischemic colitis


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Combined 05 clinical training--pathology benign_ischemic colitis

  1. 1. The Next Era in GI Surgery BioDynamix TM Anastomosis The Colon Ring Clinical Training Team BENIGN PATHOLOGY Ischemic Colitis
  2. 2. Ischemic Colitis – Introduction <ul><li>Ischemic colitis is a medical condition in which inflammation and injury of the large intestine result from inadequate blood supply. </li></ul><ul><li>Ischemic colitis occurs mostly in the elderly and is the most common form of bowel ischemia. </li></ul><ul><li>Causes of reduced blood flow can include changes in the systemic circulation or local factors, such as constriction of blood vessels or a blood clot . </li></ul><ul><li>Ischemic colitis can span a wide spectrum of severity; most patients are treated supportively and recover fully, while a minority with very severe ischemia may develop sepsis and become critically ill. </li></ul>
  3. 3. Ischemic Colitis
  4. 4. Ischemic Colitis – Causes and Epidemiology <ul><li>Ischemic colitis is responsible for about 1 in 2000 hospital admissions and is seen on about 1 in 100 endoscopies. </li></ul><ul><li>Men and women are affected equally. </li></ul><ul><li>Ischemic colitis is a disease of the elderly, with more than 90% of cases occurring in people over the age of 60. </li></ul><ul><li>Ischemic colitis is often classified according to the underlying cause. </li></ul><ul><ul><li>Occlusive ischemia indicates that a blood clot or other blockage has cut off blood flow to the colon. </li></ul></ul><ul><ul><li>Non-occlusive ischemia develops because of low blood pressure or constriction of the vessels feeding the colon. </li></ul></ul>
  5. 5. Ischemic Colitis – Causes and Epidemiology <ul><li>Occlusive ischemia— </li></ul><ul><ul><li>Mostly the result of a thromboembolism . Commonly, the embolism is caused by atrial fibrillation , valvular disease , myocardial infarction , or cardiomyopathy . </li></ul></ul><ul><li>Non-occlusive ischemia— </li></ul><ul><ul><li>In hemodynamically unstable patients (i.e. shock), the mesenteric perfusion may be compromised. This condition is commonly asymptomatic and usually only apparent through a systemic inflammatory response. </li></ul></ul>
  6. 6. Ischemic Colitis – Pathophysiology <ul><li>Colonic blood supply </li></ul><ul><ul><li>The colon receives blood from both the superior and inferior mesenteric arteries . </li></ul></ul><ul><ul><li>The blood supply from these two major arteries overlap with abundant collateral circulation . </li></ul></ul><ul><ul><li>There are vascular “weak” points , at the borders of the territory supplied by each of these arteries. </li></ul></ul><ul><ul><li>These watershed areas are most vulnerable to ischemia when blood flow decreases, as they have the fewest vascular collaterals. </li></ul></ul><ul><ul><li>The rectum receives blood from both the inferior mesenteric artery and the internal iliac arter ies . </li></ul></ul><ul><ul><li>The rectum is rarely involved with colonic ischemia due to this dual blood supply . </li></ul></ul>
  7. 7. Ischemic Colitis – Pathophysiology <ul><li>Development of ischemia— </li></ul><ul><ul><li>Under ordinary conditions, the colon receives between 10% and 35% of the total cardiac output. </li></ul></ul><ul><ul><li>If blood flow to the colon drops by more than about 50%, ischemia will develop. </li></ul></ul><ul><ul><li>The arteries feeding the colon are very sensitive to vasoconstrictors . </li></ul></ul><ul><ul><li>As a result, during periods of low blood pressure , the arteries feeding the colon clamp down vigorously. </li></ul></ul><ul><ul><li>A similar process can result from vasoconstricting drugs such as ergotamine , cocaine , or vasopressors . </li></ul></ul><ul><ul><li>This vasoconstriction can result in non-occlusive ischemic colitis . </li></ul></ul>
  8. 8. Ischemic Colitis – Signs and Symptoms <ul><li>Three progressive phases of ischemic colitis have been described: </li></ul><ul><ul><li>A hyperactive phase occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools . Many patients get better and do not progress beyond this phase. </li></ul></ul><ul><ul><li>A paralytic phase can follow if ischemia continues. In this phase, the abdominal pain becomes more widespread , the belly becomes more tender to the touch, and bowel motility decreases , resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam. </li></ul></ul><ul><ul><li>Finally, a shock phase can develop as fluids start to leak through the damaged colon lining. This can result in shock and metabolic acidosis with dehydration , low blood pressure , rapid heart rate , and confusion . Patients who progress to this phase are often critically ill and require intensive care . </li></ul></ul>
  9. 9. Ischemic Colitis – Diagnosis <ul><li>Ischemic colitis must be differentiated from the many other causes of abdominal pain and rectal bleeding (for example, infection , inflammatory bowel disease , diverticulosis , or colon cancer ). </li></ul><ul><li>It is also important to differentiate ischemic colitis, which often resolves on its own, from the more immediately life-threatening condition of acute mesenteric ischemia of the small bowel . </li></ul>
  10. 10. Ischemic Colitis – Diagnostic Tests <ul><li>There are no specific blood tests for ischemic colitis. The sensitivity of tests among 73 patients was, as follows: </li></ul><ul><ul><li>White blood cell count more than 15,000/mm 3 in 20 patients (27%) </li></ul></ul><ul><ul><li>Serum bicarbonate level less than 24 mmol/L in 26 patients (36%). </li></ul></ul><ul><li>Plain X-rays are often normal or show non-specific findings. In a series of 73 patients, plain abdominal radiography was diagnostic in 56%, showing colic distension in 53% and a pneumoperitoneum in 3%. </li></ul>
  11. 11. Ischemic Colitis – Diagnostic Tests <ul><li>CT scans are often used in the evaluation of abdominal pain and rectal bleeding, and may suggest the diagnosis of ischemic colitis, demonstrate complications, or suggest an alternate diagnosis. </li></ul><ul><li>Endoscopic evaluation, via colonoscopy or flexible sigmoidoscopy , is the procedure of choice if the diagnosis remains unclear. Ischemic colitis has a distinctive endoscopic appearance; endoscopy can also facilitate alternate diagnoses such as infection or inflammatory bowel disease . Biopsies can be taken via endoscopy to provide more definitive information. </li></ul>
  12. 12. Ischemic Colitis - Treatment <ul><li>Except in the most severe cases, ischemic colitis is treated with supportive care. IV fluids are given to treat dehydration , and the patient is placed on bowel rest until the symptoms resolve. </li></ul><ul><li>If possible, cardiac function and oxygenation should be optimized to improve oxygen delivery to the ischemic bowel. </li></ul><ul><li>A nasogastric tube may be inserted if an ileus is present. </li></ul><ul><li>If a patient develops worsening symptoms and signs, such as high white blood cell count , fever , worsened abdominal pain, or increased bleeding, he may require surgical intervention , usually consisting of laparotomy and bowel resection . </li></ul>
  13. 13. Ischemic Colitis – Long-Term Complications <ul><li>About 20% of patients with acute ischemic colitis may develop a long-term complication known as chronic ischemic colitis . </li></ul><ul><li>Symptoms can include recurrent infections, bloody diarrhea, weight loss, and chronic abdominal pain. </li></ul><ul><li>Chronic ischemic colitis is often treated with surgical removal of the chronically diseased portion of the bowel. </li></ul><ul><li>A colonic stricture is a band of scar tissue which forms as a result of the ischemic injury and narrows the lumen of the colon. </li></ul><ul><li>If bowel obstruction develops as a result of stricture, surgical resection is the usual treatment, although endoscopic dilatation and stenting have also been employed. </li></ul>
  14. 14. Ischemic Colitis - Prognosis <ul><li>Most patients with ischemic colitis recovery fully, although the prognosis depends on the severity of the ischemia. </li></ul><ul><li>Patients with pre-existing peripheral vascular disease or ischemia of the ascending (right) colon may be at increased risk for complications or death. </li></ul><ul><li>Non-gangrenous ischemic colitis, which comprises the vast majority of cases, is associated with a mortality rate of approximately 6%. </li></ul><ul><li>The minority of patients, who develop gangrene as a result of colonic ischemia, have a mortality rate of 50-75% even with surgical treatment. </li></ul>