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Colon Ischemia

An Update for Clinicians

      Abstract

      Colon ischemia (CI) is an underrecognized entity associated with high morbidity and mortality. Establishing the diagnosis and initiating appropriate and timely treatment is critical for improving outcomes. Colon ischemia is a disease spectrum that requires a full understanding for recognition and treatment. This review outlines the full spectrum of CI management from initial presentation to medical and surgical treatment.

      Abbreviations and Acronyms:

      AMI (acute mesenteric ischemia), CI (colon ischemia), CT (computed tomography), CTA (computed tomography angiography), IBS (irritable bowel syndrome), IRCI (isolated right colon ischemia), LDH (lactate dehydrogenase), MVT (mesenteric venous thrombosis)
      CME Activity
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      Physicians should claim only the credit commensurate with the extent of their participation in the activity.
      MOC Credit Statement: Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 1 MOC point in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program. Participants will earn MOC points equivalent to the amount of CME credits claimed for the activity. It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.
      Learning Objectives: On completion of this article, you should be able to (1) identify the clinical features and presentation of colon ischemia, (2) diagnose and assess the severity of colon ischemia using a simplified algorithm, and (3) provide appropriate short-term and long-term care for patients with colon ischemia.
      Disclosures: As a provider accredited by ACCME, Mayo Clinic College of Medicine (Mayo School of Continuous Professional Development) must ensure balance, independence, objectivity, and scientific rigor in its educational activities. Course Director(s), Planning Committee members, Faculty, and all others who are in a position to control the content of this educational activity are required to disclose all relevant financial relationships with any commercial interest related to the subject matter of the educational activity. Safeguards against commercial bias have been put in place. Faculty also will disclose any off-label and/or investigational use of pharmaceuticals or instruments discussed in their presentation.
      Disclosure of this information will be published in course materials so that those participants in the activity may formulate their own judgments regarding the presentation.
      In their editorial and administrative roles, William L. Lanier, Jr, MD, Terry L. Jopke, Kimberly D. Sankey, and Nicki M. Smith, MPA, have control of the content of this program but have no relevant financial relationship(s) with industry.
      The authors report no competing interests.
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      Date of Release: 5/1/2016
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      Questions? Contact [email protected] .
      Colon ischemia (CI), as opposed to acute mesenteric ischemia (AMI) that affects the small bowel, is the most common type of mesenteric ischemia.
      • Higgins P.D.
      • Davis K.J.
      • Laine L.
      Systematic review: the epidemiology of ischaemic colitis.
      Colon ischemia is the cause of 15% of all patients hospitalized for acute lower gastrointestinal bleeding, predominantly affecting the elderly.
      • Arroja B.
      • Cremers I.
      • Ramos R.
      • et al.
      Acute lower gastrointestinal bleeding management in Portugal: a multicentric prospective 1-year survey.
      Colon ischemia can be defined as a decrease in blood flow to a level insufficient to maintain colonocyte metabolic function. It has a spectrum of manifestations including reversible colopathy (submucosal or intramural hemorrhage or edema), transient colitis evidenced by mucosal ulceration, chronic colitis, stricture, gangrene, and fulminant universal colitis. Colon ischemia has become the preferred terminology rather than ischemic colitis, as some patients do not have a documented inflammatory phase.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Colon ischemia is occurring more often, with a recent population-based study finding the incidence to be 16 cases per 100,000 person-years, which is a 4-fold increase over the past 34 years.
      • Yadav S.
      • Dave M.
      • Edakkanambeth Varayil J.
      • et al.
      A population-based study of incidence, risk factors, clinical spectrum, and outcomes of ischemic colitis.
      It is more common in women than in men,
      • Yadav S.
      • Dave M.
      • Edakkanambeth Varayil J.
      • et al.
      A population-based study of incidence, risk factors, clinical spectrum, and outcomes of ischemic colitis.
      with mortality rates ranging from 4% to 12%.
      • Yadav S.
      • Dave M.
      • Edakkanambeth Varayil J.
      • et al.
      A population-based study of incidence, risk factors, clinical spectrum, and outcomes of ischemic colitis.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      • Longstreth G.F.
      • Yao J.F.
      Epidemiology, clinical features, high-risk factors, and outcome of acute large bowel ischemia.
      Despite the increasing incidence of CI, a timely diagnosis remains a challenge for clinicians. A high index of suspicion and prompt management are important for improving outcomes. This diagnostic challenge is highlighted by a study performed in an emergency department, which found that only 10% of patients with CI presenting with abdominal pain and bloody diarrhea are correctly diagnosed at the time of the presentation.
      • Ullery B.S.
      • Boyko A.T.
      • Banet G.A.
      • Lewis L.M.
      Colonic ischemia: an under-recognized cause of lower gastrointestinal bleeding.
      Proposed reasons for this low initial diagnostic rate include the broad differential diagnosis, the nonspecific presenting symptoms in patients with multiple coexisting medical conditions, and difficulty in identifying an inciting or precipitating cause of CI. The etiology, clinical manifestations, diagnosis, and treatment of CI will be reviewed, with emphasis on a systematic evidence-based approach to management, incorporating the latest clinical guidelines
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      and most recent research.

      Etiology and Risk Factors

      The 3 main mechanisms responsible for CI include nonocclusive CI, embolic and thrombotic arterial occlusion, and mesenteric venous thrombosis (MVT). Nonocclusive CI, caused by hypoperfusion of the mesenteric microvasculature, is by far the most common mechanism, occurring in 95% of patients.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      This type of ischemia is usually most prominent at the “watershed” areas (ie, splenic flexure and rectosigmoid junction)
      • Greenwald D.A.
      • Brandt L.J.
      • Reinus J.F.
      Ischemic bowel disease in the elderly.
      ; however, any segment of the colon can be affected.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      The rectum is uncommonly involved because of a dual blood supply from both splanchnic and systemic arterial systems.
      • Bharucha A.E.
      • Tremaine W.J.
      • Johnson C.D.
      • Batts K.P.
      Ischemic proctosigmoiditis.
      Typically, nonocclusive CI is transient; however, prolonged severe ischemia causes necrosis of the mucosal layer with potential for transmural infarction.
      • Haglund U.
      • Bulkley G.B.
      • Granger D.N.
      On the pathophysiology of intestinal ischemic injury: clinical review.
      Colonic injury is related to both the hypoxic component during the episode of decreased blood flow and the sequelae of reperfusion, which is mainly seen after partial ischemia. Here, reperfusion results in the release of oxygen free radicals and other toxic by-products.
      • Granger D.N.
      • Rutili G.
      • McCord J.M.
      Superoxide radicals in feline intestinal ischemia.
      Less commonly, CI can result from arterial thromboemboli or from MVT, which almost always involves the proximal colon.
      • Clavien P.A.
      • Dürig M.
      • Harder F.
      Venous mesenteric infarction: a particular entity.
      Colon ischemia typically occurs in well-defined clinical settings, particularly in patients with vascular risk factors. These include diabetes mellitus, coronary artery disease, and peripheral vascular disease.
      • Yadav S.
      • Dave M.
      • Edakkanambeth Varayil J.
      • et al.
      A population-based study of incidence, risk factors, clinical spectrum, and outcomes of ischemic colitis.
      • Walker A.M.
      • Bohn R.L.
      • Cali C.
      • Cook S.F.
      • Ajene A.N.
      • Sands B.E.
      Risk factors for colon ischemia.
      However, it can also occur without identifiable risk factors. The heterogeneous risk factors for CI support a multifactorial pathogenesis and emphasize the importance of a careful assessment of the medical, surgical, and medication/drug use history in every patient with CI. Irritable bowel syndrome (IBS), constipation, and surgical procedures such as abdominal aortic aneurysm repair are known risk factors.
      • Chang L.
      • Kahler K.H.
      • Sarawate C.
      • Quimbo R.
      • Kralstein J.
      Assessment of potential risk factors associated with ischaemic colitis.
      • Suh D.C.
      • Kahler K.H.
      • Choi I.S.
      • Shin H.
      • Kralstein J.
      • Shetzline M.
      Patients with irritable bowel syndrome or constipation have an increased risk for ischaemic colitis.
      • Perry R.J.
      • Martin M.J.
      • Eckert M.J.
      • Sohn V.Y.
      • Steele S.R.
      Colonic ischemia complicating open vs endovascular abdominal aortic aneurysm repair.
      Interestingly, patients with IBS exhibited increased ischemic hypersensitivity as compared with the general population, which may account for the disproportionate number of patients with IBS presenting for medical evaluation of CI.
      • Zhou Q.
      • Fillingim R.B.
      • Riley III, J.L.
      • Verne G.N.
      Ischemic hypersensitivity in irritable bowel syndrome patients.
      Eliciting a thorough medication history is important, especially focused on constipation-inducing medications (eg, opioids), immunomodulators (eg, azathioprine and type I interferons), and illicit drugs (eg, cocaine).
      • Longstreth G.F.
      • Yao J.F.
      Diseases and drugs that increase risk of acute large bowel ischemia.
      • Salk A.
      • Stobaugh D.J.
      • Deepak P.
      • Ehrenpreis E.D.
      Ischemic colitis with type I interferons used in the treatment of hepatitis C and multiple sclerosis: an evaluation from the food and drug administration adverse event reporting system and review of the literature.
      • Elramah M.
      • Einstein M.
      • Mori N.
      • Vakil N.
      High mortality of cocaine-related ischemic colitis: a hybrid cohort/case-control study.
      In addition, neuromodulating and vasoconstricting medications, such as quetiapine and rizatriptan, are recognized precipitants of CI.
      • Vernay J.
      Quetiapine-induced ischemic colitis: a case report.
      • Fonseka G.R.
      • Kurchin A.
      Case report: rizatriptan-induced ischemic colitis.
      Evaluation of thrombophilia as a cause of CI should be considered in young patients and all patients with recurrent CI.
      • Midian-Singh R.
      • Polen A.
      • Durishin C.
      • Crock R.D.
      • Whittier F.C.
      • Fahmy N.
      Ischemic colitis revisited: a prospective study identifying hypercoagulability as a risk factor.
      • Theodoropoulou A.
      • Sfiridaki A.
      • Oustamanolakis P.
      • et al.
      Genetic risk factors in young patients with ischemic colitis.
      The degree to which acquired or hereditary hypercoagulable states contribute to the pathogenesis of CI is not well understood. However, the prevalence of antiphospholipid antibodies, plasminogen activator inhibitors, and factor V Leiden sequence variations are increased in patients with CI.
      • Theodoropoulou A.
      • Sfiridaki A.
      • Oustamanolakis P.
      • et al.
      Genetic risk factors in young patients with ischemic colitis.

      Clinical Manifestations

      The clinical manifestations of CI vary depending on the extent and duration of ischemia. Most patients have self-limiting, nongangrenous ischemia, which typically resolves completely.
      • Greenwald D.A.
      • Brandt L.J.
      Colonic ischemia.
      However, approximately 10% of patients develop colonic necrosis and gangrene, which can be life-threatening.
      • Montoro M.A.
      • Brandt L.J.
      • Santolaria S.
      • et al.
      Workgroup for the Study of Ischaemic Colitis of the Spanish Gastroenterological Association (GTECIE-AEG)
      Clinical patterns and outcomes of ischaemic colitis: results of the Working Group for the Study of Ischaemic Colitis in Spain (CIE study).
      These patients have a more protracted hospital course and tend to develop long-term complications, such as chronic ischemic colitis or strictures.
      Patients with CI typically present with abrupt, cramping abdominal pain of mild to moderate severity that often affects the left side of the abdomen. This is often accompanied by an urgent desire to defecate and the subsequent passage of bloody diarrhea within 24 hours.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      • Longstreth G.F.
      • Yao J.F.
      Epidemiology, clinical features, high-risk factors, and outcome of acute large bowel ischemia.
      Colon ischemia should be considered when the presenting symptoms are abdominal pain and bloody diarrhea.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      • Longstreth G.F.
      • Yao J.F.
      Epidemiology, clinical features, high-risk factors, and outcome of acute large bowel ischemia.
      Compared with ischemia affecting the small intestine, the cramping pain that accompanies CI is less severe and is felt laterally rather than periumbilically.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      • Longstreth G.F.
      • Yao J.F.
      Epidemiology, clinical features, high-risk factors, and outcome of acute large bowel ischemia.
      In addition, gastrointestinal hemorrhage is an unusual presentation of AMI. In severe forms of CI, transmural infarction occurs with resultant gangrenous colitis, which is characterized by increasing abdominal tenderness, peritoneal signs, fever, and ileus. The sudden onset of a toxic colitis with signs of peritonitis and a rapidly progressive course are hallmarks of universal fulminant colitis, a rare variant of CI.
      Colon ischemia tends to be a segmental process that is explained by the colon being perfused by 3 vessels: the superior mesenteric artery, the inferior mesenteric artery, and the internal iliac artery.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      Although CI is often segmental and involves the left colon, it is recognized that isolated right colon ischemia (IRCI) has a different clinical presentation and worse outcomes than does CI affecting any other region of the colon.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.
      • Sotiriadis J.
      • Brandt L.J.
      • Behin D.S.
      • Southern W.N.
      Ischemic colitis has a worse prognosis when isolated to the right side of the colon.
      In addition, CI may have a pancolonic distribution that carries a poor prognosis similar to that of IRCI, with a mortality rate of up to 21%.
      • Brandt L.J.
      • Feuerstadt P.
      • Blaszka M.C.
      Anatomic patterns, patient characteristics, and clinical outcomes in ischemic colitis: a study of 313 cases supported by histology.

      Diagnosis

      A diagnosis of CI is usually suspected on the basis of history, physical examination, and clinical setting. The differential diagnosis in patients presenting with abdominal pain and bloody diarrhea is broad and includes inflammatory bowel disease, infectious colitis, and colonic adenocarcinoma. Initial laboratory studies should include complete blood count, metabolic panel, serum lactate level, lactate dehydrogenase (LDH) level, creatine kinase level, and amylase level. White blood cell count is useful for prognostic purposes, hemoglobin level evaluates blood loss, and acid/base status can be assessed from bicarbonate, lactate, and LDH levels. Elevated amylase levels are associated with acute bowel ischemia.
      • Theodoropoulou A.
      • Koutroubakis I.E.
      Ischemic colitis: clinical practice in diagnosis and treatment.
      Although these laboratory tests are not diagnostic for CI, obtaining them during the initial work-up helps in risk stratification. Synchronous stool studies should be ordered to rule out an infectious etiology of bloody diarrhea, including stool culture, ova and parasite testing, and Clostridium difficile toxin assay. Although C difficile infection rarely presents with bloody diarrhea, given its increasing incidence and severity, testing for it should be part of the initial assessment.
      Computed tomography (CT) with intravenous and oral contrast is recommended as the first imaging modality for patients with suspected CI to assess the distribution and phase of colitis.
      • Romano S.
      • Romano L.
      • Grassi R.
      Multidetector row computed tomography findings from ischemia to infarction of the large bowel.
      • Menke J.
      Diagnostic accuracy of multidetector CT in acute mesenteric ischemia: systematic review and meta-analysis.
      The diagnosis of CI can be suggested on the basis of CT findings (eg, edema, bowel wall thickening, and thumbprinting).
      • Romano S.
      • Romano L.
      • Grassi R.
      Multidetector row computed tomography findings from ischemia to infarction of the large bowel.
      • Menke J.
      Diagnostic accuracy of multidetector CT in acute mesenteric ischemia: systematic review and meta-analysis.
      Initial CT scans may be nonspecific with segmental wall thickening which also may be seen with infectious and Crohn colitis.
      Formal vascular imaging studies are usually not indicated in patients with suspected CI because at the time of the presentation, blood flow has usually returned to normal levels in the most common nonocclusive type of CI. The subsequent pathological changes reflect the ischemic insult to the colonic mucosa with reperfusion injury, rather than from ongoing ischemia. Multiphasic CT angiography (CTA) should be performed on any patient with IRCI, as the ischemic episode may be the heralding event of a focal occlusion by embolus or thrombus of the superior mesenteric artery with impending AMI. Furthermore, CTA should be pursued in any patient in whom the possibility of AMI cannot be excluded.
      • Menke J.
      Diagnostic accuracy of multidetector CT in acute mesenteric ischemia: systematic review and meta-analysis.
      Severe pain that is “out of proportion” to physical examination without bleeding is characteristic of AMI. Computed tomographic or magnetic resonance imaging findings of colonic pneumatosis and portomesenteric venous gas suggest transmural colonic infarction complicating CI, which mandates urgent exploratory laparotomy.
      • Milone M.
      • Di Minno M.N.
      • Musella M.
      • et al.
      Computed tomography findings of pneumatosis and portomesenteric venous gas in acute bowel ischemia.
      In a patient in whom the presentation of CI may be a heralding sign of AMI and who has a negative finding on multiphasic CTA, traditional splanchnic angiography should be considered.
      • Menke J.
      Diagnostic accuracy of multidetector CT in acute mesenteric ischemia: systematic review and meta-analysis.
      The role of other types of imaging is limited. A plain abdominal radiograph is frequently nonspecific with bowel distension or pneumatosis observed only in advanced ischemia with infarction. Barium enema has been superseded by CT and colonoscopy. Magnetic resonance imaging has been studied in only a small number of patients with CI, with findings being similar to those of CT.
      • Mazzei M.A.
      • Guerrini S.
      • Cioffi Squitieri N.
      • et al.
      Magnetic resonance imaging: is there a role in clinical management for acute ischemic colitis?.
      Overall, imaging can suggest or support the diagnosis of CI, but none of the imaging findings are specific enough to make a diagnosis, except when infarction has occurred.
      Colonoscopy is the principal modality used to diagnose CI, usually after CT reveals nonspecific thickening of a colon segment. Colonoscopy allows tissue sample acquisition and direct visualization of the colonic mucosa. Common findings in transient CI are edematous and fragile mucosa, segmental erythema, scattered erosions, longitudinal ulcerations, petechial hemorrhages interspersed with pale areas, purple hemorrhagic nodules, and a sharply defined segmental involvement.
      • Zou X.
      • Cao J.
      • Yao Y.
      • Liu W.
      • Chen L.
      Endoscopic findings and clinicopathologic characteristics of ischemic colitis: a report of 85 cases.
      The colon single-stripe sign is a highly specific sign of CI, defined as a single inflammatory band of erythema with erosion along the longitudinal axis of the colon.
      • Zuckerman G.R.
      • Prakash C.
      • Merriman R.B.
      • Sawhney M.S.
      • DeSchryver-Kecskemeti K.
      • Clouse R.E.
      The colon single-stripe sign and its relationship to ischemic colitis.
      Early colonoscopy, within 48 hours of presentation, should be performed in patients with suspected CI to confirm the diagnosis.
      • Montoro M.A.
      • Brandt L.J.
      • Santolaria S.
      • et al.
      Workgroup for the Study of Ischaemic Colitis of the Spanish Gastroenterological Association (GTECIE-AEG)
      Clinical patterns and outcomes of ischaemic colitis: results of the Working Group for the Study of Ischaemic Colitis in Spain (CIE study).
      • Kozarek R.A.
      • Earnest D.L.
      • Silverstein M.E.
      • Smith R.G.
      Air-pressure-induced colon injury during diagnostic colonoscopy.
      In patients with severe CI, limited colonoscopy with biopsies, stopping at the distal most extent of disease, should be performed to confirm the nature of the CT abnormality. Biopsies should be deferred in cases of gangrene. Colonoscopy should not be performed in patients who have signs of acute peritonitis or evidence of irreversible ischemic damage on imaging studies. Sigmoidoscopy is limited in its ability to reliably diagnose CI.
      • Houe T.
      • Thorböll J.E.
      • Sigild U.
      • Liisberg-Larsen O.
      • Schroeder T.V.
      Can colonoscopy diagnose transmural ischaemic colitis after abdominal aortic surgery? An evidence-based approach.
      If the diagnosis remains in question, abdominal exploration may be needed.

      Clinical Management

      A proposed algorithm for the management of CI (adapted from recent guidelines
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      ) is shown in the Figure. Before deciding on the appropriate management, patients should be risk stratified into mild, moderate, or severe disease, with tailored treatment promptly initiated.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Patients with mild disease have typical symptoms of CI, with a segmental colitis not isolated to the right colon and absence of the poor prognostic factors observed in moderate disease.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Moderate disease includes any patient with up to 3 of the following factors: male sex, hypotension, tachycardia, abdominal pain without rectal bleeding, blood urea nitrogen level greater than 20 mg/dL, hemoglobin level less than 12 g/dL, LDH level greater than 350 U/L, serum sodium level less than 136 mEq/L, white blood cell count greater than 15×109/L, or colonoscopically identified mucosal ulceration.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Severe disease is defined by more than 3 of the previously listed criteria or any of the following: peritoneal signs on physical examination, pneumatosis or portal venous gas on CT, gangrene on colonoscopy, or a pancolonic distribution or IRCI on CT or colonoscopy.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Finally, chronic kidney disease with dialysis or poor Eastern Cooperative Oncology Group status has recently been shown to be an independent risk factor for severe disease,
      • Choi S.R.
      • Jee S.R.
      • Song G.A.
      • et al.
      Predictive factors for severe outcomes in ischemic colitis.
      but is not included in the American College of Gastroenterology risk-stratifying model.
      Figure thumbnail gr1
      FigureManagement algorithm for colon ischemia. BUN = blood urea nitrogen; CI = colon ischemia; CT = computed tomography; CTA = computed tomography angiography; Hgb = hemoglobin; HR = heart rate; ICU = intensive care unit; IRCI = isolated right colon ischemia; IVF = intravenous fluid; LDH = lactate dehydrogenase; MRA = magnetic resonance angiography; PVG = portal venous gas; SBP = systolic blood pressure; WBC = white blood cell count. aPoor prognostic risk factors: male sex, hypotension (SBP<90 mm Hg), tachycardia (HR>100 beats/min), pain without rectal bleeding, BUN level >20 mg/dL, Hgb level <12 g/dL, LDH level >350 U/L, serum sodium level <136 mEq/L, WBC >15×109/L.
      Adapted from Am J Gastroenterol,
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      with permission.
      Most cases of CI resolve spontaneously and do not require specific therapy. These patients have reversible ischemic colopathy or transient ulcerating CI.
      • Mosele M.
      • Cardin F.
      • Inelmen E.M.
      • et al.
      Ischemic colitis in the elderly: predictors of the disease and prognostic factors to negative outcome.
      • Añón R.
      • Boscá M.M.
      • Sanchiz V.
      • et al.
      Factors predicting poor prognosis in ischemic colitis.
      Patients with more significant disease require hospitalization to monitor for complications and signs of irreversible disease. Initial medical management centers on general supportive measures such as bowel rest, intravenous hydration, and correction of precipitating conditions.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Parenteral nutrition may be indicated if a protracted course is predicted. No specific therapeutic modality has ever been tested in a clinical trial setting. Broad-spectrum antimicrobial therapy should be considered for patients with moderate or severe disease,
      • Mosele M.
      • Cardin F.
      • Inelmen E.M.
      • et al.
      Ischemic colitis in the elderly: predictors of the disease and prognostic factors to negative outcome.
      • Añón R.
      • Boscá M.M.
      • Sanchiz V.
      • et al.
      Factors predicting poor prognosis in ischemic colitis.
      • Yoshiya K.
      • Lapchak P.H.
      • Thai T.H.
      • et al.
      Depletion of gut commensal bacteria attenuates intestinal ischemia/reperfusion injury.
      because of the perceived increased risk of bacterial translocation in the setting of acute ischemia and reperfusion injury. The antibiotic regimen typically consists of an antianaerobic agent plus a fluoroquinolone.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Glucocorticoids have no role, unless the CI is a complication of vasculitis. Antithrombotic therapy is not indicated for most patients with CI as most patients have nonocclusive ischemia. However, anticoagulant therapy is indicated when ischemia develops owing to MVT or ischemia secondary to cardiac thromboembolization. If a cardiac source of embolism is suspected, an electrocardiogram, Holter monitoring, and transthoracic echocardiogram should be obtained.
      Surgical intervention should be considered in the presence of CI accompanied by peritonitis, hemodynamic instability, IRCI, and pancolonic CI as well as in the presence of gangrene.
      • Montoro M.A.
      • Brandt L.J.
      • Santolaria S.
      • et al.
      Workgroup for the Study of Ischaemic Colitis of the Spanish Gastroenterological Association (GTECIE-AEG)
      Clinical patterns and outcomes of ischaemic colitis: results of the Working Group for the Study of Ischaemic Colitis in Spain (CIE study).
      • Mosele M.
      • Cardin F.
      • Inelmen E.M.
      • et al.
      Ischemic colitis in the elderly: predictors of the disease and prognostic factors to negative outcome.
      • Añón R.
      • Boscá M.M.
      • Sanchiz V.
      • et al.
      Factors predicting poor prognosis in ischemic colitis.
      Without surgical intervention, mortality from necrotic bowel approaches 100%, and mortality after surgical intervention for CI is upward toward 50%.
      • Castleberry A.W.
      • Turley R.S.
      • Hanna J.M.
      • et al.
      A 10-year longitudinal analysis of surgical management for acute ischemic colitis.
      • Antolovic D.
      • Koch M.
      • Hinz U.
      • et al.
      Ischemic colitis: analysis of risk factors for postoperative mortality.
      The surgical procedure depends on the nature and extent of the CI but most commonly includes total or subtotal colectomy, right hemicolectomy, or segmental colectomy with either a primary anastomosis or a diverting stoma.
      Patients with CI can develop sequelae of the disease, even after reperfusion. Therefore, close follow-up is important after an episode of CI. The management approach to CI is outlined in the Table. Strategies for prevention of recurrent episodes of CI should focus on blood pressure management to ensure optimal colonic perfusion, aggressive treatment of constipation, and education on maintaining appropriate hydration, especially in the setting of illness or exercise. A full medication review should occur, with attention to medications listed earlier in this review. Moreover, in young patients (<40 years of age) with CI or those presenting with recurrent CI without obvious risk factors, evaluation of hypercoagulable states should be considered.
      • Sotiriadis J.
      • Brandt L.J.
      • Behin D.S.
      • Southern W.N.
      Ischemic colitis has a worse prognosis when isolated to the right side of the colon.
      • Theodoropoulou A.
      • Koutroubakis I.E.
      Ischemic colitis: clinical practice in diagnosis and treatment.
      • Romano S.
      • Romano L.
      • Grassi R.
      Multidetector row computed tomography findings from ischemia to infarction of the large bowel.
      Of note, severe ischemia causes ulceration and inflammation, which may evolve into segmental ulcerating colitis or fibrotic strictures. These lesions may be asymptomatic, but they should be followed by repeat endoscopy to document healing or the development of persistent colitis or stricture.
      • Brandt L.J.
      • Feuerstadt P.
      • Longstreth G.F.
      • Boley S.J.
      American College of Gastroenterology
      ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI).
      Colonic strictures can usually be observed, with surgery indicated only when symptomatic. Endoscopic dilation of an ischemic stricture is an alternative to surgery, although this modality has not been formally evaluated in strictures secondary to CI. Recurrent episodes of bacteremia or sepsis in patients with unhealed areas of segmental colitis are indications for elective segmental colon resection.
      TableManagement Spectrum of CI
      Emergency department
      • Consider CI in all patients with acute abdominal pain and/or BRBPR
      • Laboratory studies include CBC, metabolic panel, LDH level, and amylase level
      • Stool studies include culture, O&P testing, and Clostridium difficile toxin assay
      • Imaging includes CT abdomen with oral and IV contrast
      • Risk stratification into mild, moderate, and severe disease with appropriate disposition
      Inpatient medical management
      • CT abdomen (if not already obtained)
      • CTA not indicated, unless IRCI suspected, or concerns for impending AMI (atrial fibrillation and severe pain without BRBPR)
      • Early colonoscopy for diagnosis (limited colonoscopy in severe disease)
      • Supportive management (bowel rest, IV hydration, reversal of precipitants, and antibiotics if indicated)
      • Close monitoring, in case surgical intervention warranted
      Inpatient surgical management
      • Indications include peritonism, hemodynamic instability, evidence of gangrene, and universal fulminant colitis
      • Surgical procedure includes total or subtotal colectomy, right hemicolectomy, or segmental colectomy with either a primary anastomosis or a diverting stoma
      Outpatient follow-up
      • Monitor for long-term complications:
        • Recurrent CI: review medication list and blood pressure trend; evaluate for constipation; educate on oral hydration; and consider hypercoagulable states
        • Persistent colitis or stricture: consider repeat endoscopy and/or surgery
        • Recurrent episodes of bacteremia: consider surgery
      AMI = acute mesenteric ischemia; BRBPR = bright red blood per rectum; CBC = complete blood count; CI = colon ischemia; CT = computed tomography; CTA = computed tomography angiogram; IRCI = isolated right colon ischemia; IV = intravenous; LDH = lactate dehydrogenase; O&P = ova and parasite.

      Conclusion

      Colon ischemia is a common cause of abdominal pain and lower gastrointestinal bleeding, but recognition of the disease at the initial presentation remains low. Given the potential for high morbidity and mortality, clinicians need to suspect CI in all cases of abdominal pain and bloody diarrhea to allow prompt diagnosis and reversal of precipitants. Close follow-up is important after recovery from CI to assess for the development of late complications.

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