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ischemic colitis; ischemic bowel; colonic ischemia

Etiology: 1) arterial a) hypoperfusion 1] decreased cardiac output 2] cardiac arrhythmias 3] sepsis with shock 4] vasocontriction due to vasopressors 5] diversion of blood supply a] long-distance running b] may be aggravated by high altitude 6] dehydration [3] b) thrombosis of the inferior mesenteric artery c) embolic 1] arterial emboli 2] cholesterol emboli 2) drug-induced a) cocaine b) digoxin c) estrogens d) pseudoephedrine 3) post-operative a) CABG b) abdominal aortic aneurysm surgical repair 4) vasculitis: systemic lupus erythematosus 5) hypercoagulable state 6) risk factors [3,4] - hypertension - coronary artery disease - peripheral vascular disease - atrial fibrillation - diabetes mellitus - chronic renal failure Epidemiology: 1) much more common than acute or chronic mesenteric ischemia 2) occurs in older patients with atherosclerosis 3) 90% of patients > 60 years of age 4) occurs in others (see etiology) 5) more common in women [3] Pathology: 1) most commonly affected sites a) right colon (25%) b) transverse colon (10%) c) left colon (33%) d) sigmoid colon (25%) e) may involve watershed areas between arterial supply, such as splenic flexure & rectosigmoid [3] 2) involvement of the ascending colon (right side) a) suggests concurrent mesenteric ischemia (right colon supplied by superior mesenteric artery) b) associated with worse outcomes [2] Clinical manifestations: 1) left lower quadrant pain is generally mild 2) self-limited bloody diarrhea, urgent defecation, tenesmus 3) rectal blooding (BRBPR) or maroon color 4) bleeding insufficient to require transfusion 5) mild abdominal tenderness over involved segment of colon 6) hypoactive bowel sounds (case description) [1] 7) abdominal distension (case description) [1] 8) nausea may occur [3] 9) patients do not appear very ill 10) hypovolemia & peritonitis herald intestinal gangrene, intestinal perforation or transmural necrosis Laboratory: - complete blood count (CBC) - leukocytosis may be observed (case description) [1] - basic metbolic panel - serum glucose - serum creatinine - serum bicarbonate - INR - stool studies for Clostridium difficile (GRS9) [3]* - presumably Clostridium difficile enterotoxin A+B in stool or Clostridium difficile toxin genes in stool with fast turnaround, but test specifics omitted in (GRS9) [3] * priority over colonoscopy due to concern for toxic megacolon (GRS9) [3] Special laboratory: - colonoscopy within 48 hours [3] a) segmental involvement b) sharply demarcated pale mucosa with petechial bleeding c) hemorrhagic nodules d) linear & circumferential ulceration e) gangrene f) findings overlap with those of inflammatory bowel disease Radiology: - abdominal CT - segmental thickening of watershed areas between arterial supply, such as splenic flexure or rectosigmoid [3] - CT angiography is diagnostic imaging modality of choice [1] - angiography after revascularization plan established with CT angiography [1] - barium enema (no longer diagnostic procedure of choice) - thumbprinting representing submucosal hemorrahages - segmental wall thickening may be noted, especially at splenic flexure (GRS9) [3] Differential diagnosis: - diverticulitis - diverticular bleeding (without diverticulitis) is painless [1] Complications: - bowel infarction - peritonitis - hypovolemic shock - septic shock Management: 1) evidence base for management is weak a) supportive b) intravenous fluids c) antibiotics to cover anaerobes & gram negative bacteria d) bowel rest (NPO) e) most cases resolve spontaneously [1] 2) identify & correct contributing factors if feasible 3) immediate exploratory laparotomy if signs of a) peritonitis b) hypovolemic shock c) septic shock d) bowel infarction 4) prognosis a) overall mortality (12%), 20-22% with right-sided & pancolitis [2] b) 37% mortality associated with surgery c) risk factors for failure of medical management [3,5] - clopidogrel use - lack of rectal bleeding - intraperitoneal fluid identified on abdominal CT - low serum bicarbonate on hospital admission (metabilic acidosis)

General

mesenteric ischemia (ischemic enteritis) colitis

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018, 2021.
  2. Brandt LJ et al. Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: A study of 313 cases supported by histology. Am J Gastroenterol 2010 Oct; 105:2245 PMID: 20531399
  3. Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013 - Geriatric Review Syllabus, 9th edition (GRS9) Medinal-Walpole A, Pacala JT, Porter JF (eds) American Geriatrics Society, 2016 - Geriatric Review Syllabus, 10th edition (GRS10) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2019
  4. Cubiella Fernandez J, Nunez Calvo L, Gonzalez Vazquez E et al Risk factors associated with the development of ischemic colitis. World J Gastroenterol. 2010 Sep 28;16(36):4564-9. PMID: 20857527
  5. Paterno F, McGillicuddy EA, Schuster KM, Longo WE. Ischemic colitis: risk factors for eventual surgery. Am J Surg. 2010 Nov;200(5):646-50. PMID: 21056146
  6. Tadros M, Majumder S, Birk JW. A review of ischemic colitis: is our clinical recognition and management adequate? Expert Rev Gastroenterol Hepatol. 2013 Sep;7(7):605-13. Review. PMID: 24070152
  7. Trotter JM, Hunt L, Peter MB. Ischaemic colitis. BMJ. 2016 Dec 22;355:i6600. PMID: 28007701 Free Article
  8. Oglat A, Quigley EM. Colonic ischemia: usual and unusual presentations and their management. Curr Opin Gastroenterol. 2017;33:34-40. PMID: 27798439