1. Colon ischemia is the most common type of mesenteric ischemia and is often caused by non-occlusive hypoperfusion. 2. It is frequently underdiagnosed at initial presentation due to non-specific symptoms but requires prompt diagnosis and treatment to improve outcomes. 3. Establishing the diagnosis typically involves CT imaging followed by early colonoscopy within 48 hours to directly visualize mucosal changes and confirm the diagnosis.

1. Kurdistan Board GEH J Club:
Supervised by:
Dr. Mohamed Alshekhani
Professor in Medicine
MBChB-CABM-FRCP-EBGH 2016
1

2. Introduction:
• CI : is decrease in blood flow to a level insufficient to maintain
colonocyte metabolic function.
• Colon ischemia (CI), opposed to acute mesenteric ischemia (AMI) of
small bowel, is the most common type of mesenteric ischemia.
• CI is the cause of 15% of acute LGIB, predominantly elderly.
• Manifestations spectrum: reversible colopathy (submucosal or
intramural hemorrhage or edema), transient colitis evidenced by
mucosal ulceration, chronic colitis, stricture, gangrene& fulminant
universal colitis.
• CI preferred rather than ischemic colitis, as some patients do not
have a documented inflammatory phase.
• Incidence 16/100,000 person-years,with *4 increase over past 34 ys
• It is more common in women than in men, with mortality 4- 12%.

3. Introduction:
• A timely diagnosis remains a challenge for clinicians.
• A high index of suspicion needed for prompt diagnosis &
management is important for improving outcomes.
• Only 10% of patients with CI presenting with abdominal pain &
bloody diarrhea are correctly diagnosed at the time of presentation
BZ of :
• Broad DD.
• Nonspecific presenting symptoms in patients with multiple
coexisting medical conditions
• Difficulty in identifying an inciting or precipitating cause of CI.

4. Aetiology/RFs:
• The 3 main mechanisms include:
• Non-occlusive CI: caused by hypoperfusion of the mesenteric
microvasculature, is the most common mechanism, occurring in
95%, usually most prominent at the “ watershed” areas (ie, splenic
flexure & rectosigmoid junction), but any segment can be affected.
• Typically, it is transient; but prolonged severe ischemia causes
necrosis of the mucosal layer with transmural infarction.
• Occlusive CI: Embolic & thrombotic arterial occlusion.
• Mesenteric venous thrombosis (MVT).
• The rectum is uncommonly involved because of a dual blood supply
from both splanchnic & systemic arterial systems.

5. Aetiology/RFs:
• In the more common NOCI: Colonic injury from hypoxic during the
episode of decreased blood flow, theen sequelae of reperfusion,
mainly release of oxygen free radicals&other toxic by-products.
• Less commonly, CI in arterial thromboemboli or MVT, almost
always involves the proximal colon.
• Colon ischemia typically occurs in well-defined clinical settings,
particularly in patients with vascular risk factors; DM, CAD, PAD but
can also occur without identifiable risk factors.
• IBS, constipation, surgical procedures as abd aortic aneurysm repair
are known risk factors.
• IBS exhibits increased ischemic hypersensitivity compared with the
general population.

6. Aetiology/RFs:
• Medication history is important: especially constipation-inducing
medications (eg, opioids), immunomodulators (eg, azathioprine &
interferons)& illicit drugs (eg, cocaine), neuromodulaters,
vasoconsters, such as quetiapine & rizatriptan, are recognized
precipitants of CI.
• Evaluation of thrombophilia as a cause of CI should be considered in
young patients & all patients with recurrent CI.
• The degree to which acquired or hereditary hypercoagulable states
contribute to the pathogenesis of CI is not well understood.
• The prevalence of antiphospholipid antibodies, plasminogen
activator inhibitors, factor V Leiden sequence variations are
increased in patients with CI.

7. Clinical features:
• Vary depending on the extent & duration of ischemia.
• Most have self-limiting,non-gangrenous& resolveing completely.
• 10% of patients develop colonic necrosis & gangrene, can be life-
threatening &more protracted hospital course & tend to develop
long-term complications, as chronic ischemic colitis or strictures.
• Patients typically present with abrupt, cramping abd pain of mild to
moderate severity that often affects the left side of the abdomen,
often accompanied by an urgent desire to defecate & the
subsequent passage of bloody diarrhea within 24 hours.
• Colon ischemia should be considered when the presenting
symptoms are abdominal pain&bloody diarrhea.
• Compared with AMI cramping pain that accompanies CI is less
severe & felt laterally rather than periumbilically&GIB is an unusual
presentation of AMI.

8. Diagnosis : History, PE
• Usually suspected on the basis of history, PE &clinical setting.
• DD is broad & includes IBD, infectious colitis, CRC.

9. Diagnosis : Initial Lab tests
• Although not diagnostic, it helps in risk stratifiation.
• Initial lab studies should include CBC, metabolic panel, s. lactate ,
LDH, CK, amylase.
• WBC is useful for prognostic purposes.
• Hb evaluates blood loss.
• Acid/base status can be assessed from bicarbonate, lactate, LDH.
• Elevated amylase are associated with acute bowel ischemia.
• Stool tests to rule out an infections, including stool culture,
ova/parasite testing, Clostridium difficile toxin assay.
• C difficile rarely presents with bloody diarrhea, but its increasing
incidence& severity, testing for it should be part of the initial
assessment.

10. Diagnosis:CT
• CT with IV& oral contrast is recommended as the first imaging
modality for suspected patients to assess the distribution & phase
of colitis.
• The diagnosis of CI can be suggested on the basis of CT findings (eg,
edema, bowel wall thickening, thumbprinting).
• Initial CT scans may be nonspecific with segmental wall thickening
which also may be seen with infectious & Crohn colitis.

11. Diagnosis: Angiography
• Formal vascular imaging are usually not indicated in patients with
suspected CI because at the time of the presentation, blood flow
has usually returned to normal in the most common nonocclusive
type &subsequent pathological changes reflect the ischemic insult
from reperfusion injury, rather than from ongoing ischemia.
• Multiphasic CTA should be performed on any patient with:
• 1. IRCI, as it may be the heralding event of a focal occlusion by
embolus or thrombus of the superior mesenteric artery with
impending AMI.
• 2. Any patient in whom the possibility of AMI cannot be excluded.
• Severe pain “ out of proportion” to physical examination without
bleeding is characteristic of AMI.

12. Diagnosis:
• CT or MRI findings of colonic pneumatosis & porto-mesenteric
venous gas suggest transmural colonic infarction complicating CI,
which mandates urgent exploratory laparotomy.
• In a patient in whom the presentation of CI may be a heralding sign
of AMI & who has a negative finding on multiphasic CTA, traditional
splanchnic angiography should be considered.
• MRI has been studied in only a small number of patients with CI,
with findings being similar to those of CT.
• Overall, imaging can suggest or support the diagnosis of CI, but
none of the imaging findings are specific enough.

13. Diagnosis:plain XR & Barium
• The role of other types of imaging is limited.
• A plain abd XR is frequently nonspecific with bowel distension or
pneumatosis observed only in advanced ischemia with infarction.
• Barium enema has been superseded by CT & colonoscopy.

14. Diagnosis : colonoscopy
• Is the principal modality used to diagnose CI, usually after CT
reveals non-specifi thickening of a colon segment.
• Colonoscopy allows biopsy&direct visualization colonic mucosa.
• Common findings in transient CI: edematous&fragile mucosa,
segmental erythema, scattered erosions, longitudinal ulcerations,
petechial hemorrhages interspersed with pale areas, purple
hemorrhagic nodules&sharply defined segmental involvement.
• 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.
• Early colonoscopy,within 48 hours of presentation,should be
performed in patients with suspected CI to confirm the diagnosis.
• 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.

18. Diagnosis:
• 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.
• If the diagnosis remains in question, abdominal exploration may be
needed.

19. Management:
• Patients stratified into mild, moderate, or severe disease, with
tailored treatment promptly initiated.
• Mild disease: typical symptoms of CI, with a segmental colitis not
isolated to the right colon& absence of the poor prognostic factors
observed in moderate disease.
• Moderate disease: any patient with up to 3 of: male, hypotension,
tachycardia, abd pain without rectal bleeding, BUN>20 mg/dL,
Hb<12 g/dL, LDH> 350 U/L, serum Na <136 mEq/L, WBC>15 109
/L,or colonoscopically identified mucosal ulceration.
• Severe disease: >3 of the previously listed criteria or any of the
following: peritoneal signs on PE, pneumatosis or portal venous gas
on CT, gangrene on colonoscopy, or a pancolonic distribution or IRCI
on CT or colonoscopy.
• CKD with dialysis or poor Eastern Coop Oncology Group status is
independent RF for severe disease, not included in ACG risk.

26. Abstract:
• Colon ischemia is a common cause of abd pain & lower GIB, but
recognition of the disease at the initial presentation remains low.
• Given the potential for high morbidity & mortality, clinicians need
to suspect CI in all cases of abdominal pain&bloody diarrhea to
allow prompt diagnosis& reversal of precipitants.
• Close follow-up is important after recovery from CI to assess for the
development of late complications.
• Colon ischemia (CI) is an under-recognized entity associated with
high morbidity & mortality.
• Establishing the diagnosis & initiating appropriate and timely
treatment is critical for improving outcomes.
• Colon ischemia is a disease spectrum that requires a full
understanding for recognition & treatment.

27. BO5:1
• 1. The most common type of abdominal vascular ischemia is:
• A. Colonic ischemia.
• B. Small intestinal acute vascular occlusion.
• C. Gastric ischemia.
• D. Venous occlusions.
• E. None of the above.

28. BO5:2
• 2. The most common cause of colonic ischemia is:
• A. Non-occlusive ischemia.
• B. Occlusive ischemia.
• C. Thrombosis.
• D. Embolism.
• E. Vasculitis.

29. BO5:3
• 3. At initial presentation colonic ischemia is diagnosed:
• A. Usually.
• B. Commonly
• C. rarely.
• D. Oftenly.
• E. very rarely.

30. BO5:4
• 4. Rectal sparing is characteristic of:
• A. UC.
• B. Crohn’s disease.
• C. Colonic ischemia.
• D. Clostridium difficle colitis.
• E. B & C.

31. BO5:5
• 5. Abdominal pain followed by bloody diarrhea is characteristic of :
• A. Colonic ischemia.
• B. UC.
• C. Crohn’s disease.
• D. Clostridium difficle colitis.
• E. Amebiasis.

32. BO6:6
• 6. Colon Ischemia is characteristically affecting:
• A. Splenic flexture.
• B. Right colon.
• C. Rectum.
• D. Hepatic flexture.
• E. Anal canal.

33. BO6:7
• 7. Colon Ischemia is characteristically affecting:
• A. Recto-sigmoid junction.
• B. Right colon.
• C. Rectum.
• D. Hepatic flexture.
• E. Anal canal.

34. BO6:8
• 8. Clinically acute mesenteric ischemia differs from colon Ischemia
by presence of:
• A. Central abdominal pain & bloody diarrhea.
• B. Central abdominal pain & absence of bloody diarrhea.
• C. Left-sided abdominal pain.
• D. Bloody diarrhea.
• E. Fever.

35. BO6:9
• 9. Thrombophilia as a cause of colonic Ischemia should be
suspected in:
• A. Elderly persons.
• B. All patients.
• C. All women.
• D. Young persons & in patients with recurrent disease.
• E. All men.

36. BO6:10
• 10. The principal modality to diagnose colonic ischemia is :
• A. Plain XR.
• B. CT.
• C. CTA.
• D. Colonoscopy.
• E. MRI.

37. BO6:11
• 11. In suspected colonic ischemia colonoscopy should be performed
within:
• A. 12 hours.
• B. 24 hours.
• C. 48 hours.
• D. 72 hours.
• E. 96 hours.

38. BO6:12
• 12. The initial diagnostic tool to diagnose suspected colonic
ischemia is:
• A. Plain abdominal XR.
• B. Colonoscopy.
• C. Barium enema.
• D. CT scan.
• E. MRI.