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Clinical approach to colonic ischemia

Cleveland Clinic Journal of Medicine. 2009 July;76(7):401-409 | 10.3949/ccjm.76a.08089
July 1, 2009|Cleveland Clinic Journal of Medicine
Kareem Elder, MD;Bret A. Lashner, MD;Firas Al Solaiman, MD
Author and Disclosure Information

Kareem Elder, MD
Department of Internal Medicine, Collinwood Health Center, Cleveland, OH

Bret A. Lashner, MD
Department of Gastroenterology and Hepatology, Cleveland Clinic

Firas Al Solaiman, MD
Department of Cardiovascular Medicine, Cleveland Clinic

Address: Firas Al Solaiman, MD, Department of Vascular Medicine, J3-5, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; e-mail alsolaf@ccf.org

ABSTRACTTypical clinical manifestations of colonic ischemia include rapid onset of mild abdominal pain and tenderness over the affected bowel, followed by a mild amount of hematochezia within a day of the onset of pain. Most patients have transient, nongangrenous ischemia, but some have severe ischemia.

KEY POINTS

  • The incidence of colonic ischemia is difficult to ascertain, as most cases are transient and either not reported or misdiagnosed.
  • Most cases are in the elderly.
  • The clinical presentation is not specific, as other conditions also present with abdominal pain and hematochezia.
  • The most common mechanisms are hypotension and hypovolemia caused by dehydration or bleeding that results in systemic hypoperfusion.
  • Endoscopy has become the diagnostic procedure of choice.
  • Although most patients can be treated conservatively with intravenous fluids, bowel rest, and antibiotics, some develop peritonitis or clinically deteriorate and require surgery.

CLINICAL MANIFESTATIONS

As stated above, ischemic colitis should be included in the differential diagnosis when assessing patients with abdominal pain, diarrhea, or bloody stools.

Typical presentation

The typical presentation of acute colonic ischemia includes:

  • Rapid onset of mild abdominal pain
  • Tenderness over the affected bowel area, usually on the left side near the splenic flexure or the rectosigmoid junction
  • Mild to moderate hematochezia beginning within 1 day of the onset of abdominal pain. The bleeding is often not profuse and does not cause hemodynamic instability or require transfusion.40

Differentiate from mesenteric ischemia

It is important to differentiate between ischemic colitis and mesenteric ischemia, which is more serious and affects the small bowel.

Most patients with acute mesenteric ischemia complain of sudden onset of severe abdominal pain out of proportion to the tenderness on physical examination, they appear profoundly ill, and they do not have bloody stools until the late stages. They need urgent mesenteric angiography or another fast imaging test.4

In contrast, many patients with chronic mesenteric ischemia (or “abdominal angina”) report recurrent severe postprandial abdominal pain, leading to fear of food and weight loss.

Varies in severity

The severity of ischemic colitis varies widely, with hypoperfusion affecting as little as a single segment or as much as the entire colon. Over three-fourths of cases are the milder, nongangrenous form, which is temporary and rarely causes long-term complications such as persistent segmental colitis or strictures.41 In contrast, gangrenous colonic ischemia, which accounts for about 15% of cases, can be life-threatening.

Colonic ischemia can be categorized according to its severity and clinical presentation42:

  • Reversible colonopathy (submucosal or intramural hemorrhage)
  • Transient colitis (45% of cases were reversible or transient in a 1978 report by Boley et al43)
  • Chronic colitis (19% of cases)
  • Stricture (13%)
  • Gangrene (19%)
  • Fulminant universal colitis.

The resulting ischemic injury can range from superficial mucosal damage to mural or even full-thickness transmural infarction.44

Although most cases involve the left colon, about one-fourth involve the right. Right-sided colonic ischemia tends to be more severe: about 60% of patients require surgery (five times more than with colitis of other regions), and the death rate is twice as high (close to 23%).45

DIAGNOSIS DEPENDS ON SUSPICION

The diagnosis of colonic ischemia largely depends on clinical suspicion, especially since many other conditions (eg, infectious colitis, inflammatory bowel disease, diverticulitis, colon cancer) present with abdominal pain, diarrhea, and hematochezia. One study showed that a clinical presentation of lower abdominal pain or bleeding, or both, was 100% predictive of ischemic colitis when accompanied by four or more of the following risk factors: age over 60, hemodialysis, hypertension, hypoalbuminemia, diabetes mellitus, or drug-induced constipation. 46

Stool studies can identify organisms

Invasive infections with Salmonella, Shigella, and Campylobacter species and Eschericia coli O157:H7 should be identified early with stool studies if the patient presents as an outpatient or has been hospitalized less than 72 hours. Parasites such as Entamoeba histolytica and Angiostrongylus costaricensis and viruses such as cytomegalovirus should be considered in the differential diagnosis, as they can cause ischemic colitis.41,47Clostridium difficile should be excluded in those exposed to antibiotics.

Blood tests may indicate tissue injury

Although no laboratory marker is specific for ischemic colitis, elevated serum levels of lactate, lactate dehydrogenase, creatine kinase, or amylase may indicate tissue injury. The combination of abdominal pain, a white blood cell count greater than 20 × 109/L, and metabolic acidosis suggests intestinal ischemia and infarction.

Endoscopy is the test of choice

Endoscopy has become the diagnostic test of choice in establishing the diagnosis of ischemic colitis, although computed tomography (CT) can provide suggestive findings and exclude other illnesses. Colonoscopy has almost completely replaced radiography with bariumenema contrast as a diagnostic tool because it is more sensitive for detecting mucosal changes, it directly visualizes the mucosa, and it can be used to obtain biopsy specimens.48

Colonoscopy is performed without bowel preparation to prevent hypoperfusion caused by dehydrating cathartics. In addition, the scope should not be advanced beyond the affected area, and minimal air insufflation should be used to prevent perforation.

Endoscopic findings can help differentiate ischemic colitis from other, clinically similar diseases. For instance, unlike irritable bowel disease, ischemic colitis tends to affect a discrete segment with a clear delineation between affected and normal mucosa, it spares the rectum, the mucosa heals rapidly as seen on serial colonoscopic examinations, and a single linear ulcer, termed the “single-stripe” sign, runs along the longitudinal axis of the colon.49,50

Figure 2. Mildly active ischemic colitis with a large superficial ulcer in the watershed area of the splenic flexure.
In early and mild disease (Figure 2), the mucosa is pale and edematous with petechiae, and the single-stripe sign is present.

Figure 3. Severely active ischemic colitis with extensive ulceration and submucosal hemorrhage distributed segmentally in the distal transverse colon and descending colon.
As ischemia progresses, hemorrhagic nodules appear (visible as “thumbprinting” on barium enema radiographs), usually in the company of erythematous mucosa with dispersed ulcerations and submucosal hemorrhage (Figure 3). Severe ischemia causing gangrene usually manifests as cyanotic mucosal nodules and hemorrhagic ulcerations.51–53

Biopsy features are not specific, as findings of hemorrhage, capillary thrombosis, granulation tissue with crypt abscesses, and pseudopolyps can also be seen in other conditions, such as Crohn disease.54,55

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