Ischemic colitis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Hamid Qazi, MD, BSc [2]
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Overview
Ischemic colitis is a medical condition in which inflammation and injury of the large intestine result from inadequate blood supply.
Historical Perspective
In 1963, Boley et al first described ischemic colitis in animal studies as vascular occlusion of the colon. In 1966, Marston et al coined the term ischemic colitis.
Classification
Ischemic colitis may be classified largely on the degree of the histopathological damage in the colonic wall: reversible colopathy (submucosal or intramural bleeding), transient colitis, chronic segmental ischemia, gangrenous colitis, and universal fulminant colitis. Also, based on its clinical course into two types: acute ischemic colitis or chronic ischemic colitis.
Pathophysiology
It is thought that ischemic colitis is the result of a sudden, temporary, reduction in blood flow that is insufficient to meet the metabolic demands of the region of colon. Ischemic change will subsequently extend from the mucosa to the serosa. Mucosal injury will develop in 20 minutes to 1 hour, and transmural infarction occurs within 8 to 16 hours. Reperfusion injury can occur with the release of reactive oxygen species, which cause lipid peroxidation within cell membranes, causing cell necrosis.
Causes
Causes of the reduced blood flow can include changes in the systemic circulation (e.g. low blood pressure) or local factors such as constriction of blood vessels or a blood clot. In most cases, no specific cause can be identified.
Differentiating Ischemic Colitis from other Diseases
Ischemic colitis must be differentiated from the many other causes of abdominal pain, rectal bleeding, and diarrhea such as infection, inflammatory bowel disease, diverticulosis, or colon cancer. 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.
Epidemiology and Demographics
Although uncommon in the general population, ischemic colitis occurs with greater frequency in the elderly, and is the most common form of bowel ischemia. Ischemic colitis is responsible for about 50 out of 100,000 hospital admissions, and is seen on about 100 in 100,000 endoscopies.
Risk factors
Risk factors associated with ischemic colitis are cardiovascular and pulmonary diseases such as atherosclerosis and atrial fibrillation, gastrointestinal disease like diarrhea, surgical history and medications.
Screening
There is insufficient evidence to recommend routine screening for ischemic colitis.
Natural History, Complications and Prognosis
Ischemic colitis can span a wide spectrum of severity. Majority of patients are treated supportively and recover fully, while a minority with very severe ischemia may develop sepsis and become critically ill. Most patients make a full recovery. Occasionally, after severe ischemia, patients may develop long-term complications such as a stricture or chronic colitis.
Diagnosis
History and Symptoms
Ischemic colitis is characterized by abdominal pain which is out of proportion to physical findings, specifically excruciating abdominal pain despite limited focal tenderness.
Physical Examination
Ischemic colitis is characterized by abdominal pain which is out of proportion to physical findings, specifically excruciating abdominal pain despite limited focal tenderness.
Laboratory Findings
There are no specific blood tests for ischemic colitis, but an elevated white blood cell count may be present.
Abdominal X Ray
Among patients with ischemic colitis, the plain X-rays are often normal or show non-specific findings.[1] In a series of 73 patients, plain abdominal radiography showed colonic distension in 53% of patients or a pneumoperitoneum in 3%.[2]
CT
Among patients with ischemic colitis, the CT scan shows mild to moderate diffuse bowel wall thickening and marked hyperenhancement of the mucosa.
MRI
Ultrasound
Other imaging finding
Other Diagnostic studies
Among patients with a suspicion of ischemic colitis, endoscopic evaluation, via colonoscopy or flexible sigmoidoscopy, is the diagnostic procedure of choice if the diagnosis remains unclear after other imaging studies.
Treatment
Medical Therapy
Except in the most severe cases, ischemic colitis is treated with supportive care.
Surgery
Patients with ischemic colitis who develop worsening symptoms and signs such as high white blood cell count, fever, worsened abdominal pain, or increased lower gastrointestinal bleeding, may require surgical intervention which often consists of laparotomy and bowel resection.
References
- ↑ Smerud M, Johnson C, Stephens D (1990). "Diagnosis of bowel infarction: a comparison of plain films and CT scans in 23 cases". AJR Am J Roentgenol. 154 (1): 99–103. PMID 2104734.
- ↑ Huguier M, Barrier A, Boelle PY, Houry S, Lacaine F (2006). "Ischemic colitis". Am. J. Surg. 192 (5): 679–84. doi:10.1016/j.amjsurg.2005.09.018