Ischemic colitis (also spelled ischaemic colitis) is a medical condition in which inflammation and injury of the large intestine result from inadequate blood supply. Although uncommon in the general population, ischemic colitis occurs with greater frequency in the elderly, and is the most common form of bowel ischemia. http://www.guideline.gov/summary/summary.aspx?ss=15&doc_id=3069&nbr=2295 Causes of the reduced blood flow can include changes in the systemic circulation (e.g.

low blood pressure Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the di ...

) or local factors such as constriction of blood vessels or a

blood clot A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of ...

. In most cases, no specific cause can be identified. Ischemic colitis is usually suspected on the basis of the clinical setting,

physical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the pati ...

, and laboratory test results; the diagnosis can be confirmed by

endoscopy An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are inse ...

or by using sigmoid or endoscopic placement of a visible light spectroscopic catheter (see

Diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engin ...

). Ischemic colitis can span a wide spectrum of severity; most patients are treated supportively and recover fully, while a minority with very severe ischemia may develop

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...

and become critically, sometimes fatally, ill. Patients with mild to moderate ischemic colitis are usually treated with IV fluids,

analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professional ...

, and bowel rest (that is, no food or water by mouth) until the symptoms resolve. Those with severe ischemia who develop complications such as sepsis, intestinal gangrene, or

bowel perforation Gastrointestinal perforation, also known as ruptured bowel, is a hole in the wall of part of the gastrointestinal tract. The gastrointestinal tract includes the esophagus, stomach, small intestine, and large intestine. Symptoms include severe abd ...

may require more aggressive interventions such as surgery and

intensive care Intensive care medicine, also called critical care medicine, is a medical specialty that deals with seriously or critically ill patients who have, are at risk of, or are recovering from conditions that may be life-threatening. It includes pro ...

. Most patients make a full recovery; occasionally, after severe ischemia, patients may develop long-term complications such as a stricture or chronic

colitis Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification ...

Signs and symptoms

Three progressive phases of ischemic colitis have been described: * A ''hyperactive'' phase occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools. Many patients get better and do not progress beyond this phase. * A ''paralytic'' phase can follow if ischemia continues; in this phase, the abdominal pain becomes more widespread, the belly becomes more tender to the touch, and bowel

motility Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ...

decreases, resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam. * Finally, a ''shock'' phase can develop as fluids start to leak through the damaged colon lining. This can result in

shock Shock may refer to: Common uses Collective noun *Shock, a historic commercial term for a group of 60, see English numerals#Special names * Stook, or shock of grain, stacked sheaves Healthcare * Shock (circulatory), circulatory medical emergen ...

and

metabolic acidosis Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...

with

dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...

, rapid heart rate, and confusion. Patients who progress to this phase are often critically ill and require

. Symptoms of ischemic colitis vary depending on the severity of the ischemia. The most common early signs of ischemic colitis include

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Common causes of pain in the abdomen include gastroenteritis and irritable bowel syndrome. About 15% of people have a m ...

(often left-sided), with mild to moderate amounts of rectal bleeding. The sensitivity of findings among 73 patients were: * abdominal pain (78%) * lower gastrointestinal tract bleeding (62%) * diarrhea (38%) * Fever higher than (34%) Physical examination * abdominal pain (77%) * abdominal tenderness (21%)

Causes

Ischemic colitis is often classified according to the underlying cause. ''Non-occlusive'' ischemia develops because of low blood pressure or constriction of the vessels feeding the colon; ''occlusive'' ischemia indicates that a

or other blockage has cut off blood flow to the colon.

Non-occlusive ischemia

In hemodynamically unstable patients (i.e. shock) the mesenteric perfusion may be compromised. This condition is commonly asymptomatic, and usually only apparent through a systemic inflammatory response.

Occlusive ischemia

Mostly the result of a thromboembolism. Commonly the embolism is caused by atrial fibrillation, valvular disease,

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...

, or cardiomyopathy. In addition, ischemic colitis is a well-recognized complication of abdominal aortic aneurysm repair, when the origin of the inferior mesenteric artery is covered by the aortic graft. In a 1991 review concerning 2137 patients the accidental inferior mesenteric artery ligation was the most common cause (74%) of ischemic colitis. Thus, patients without adequate collateralization are at risk for ischemia of the descending and sigmoid colon. Bloody diarrhea and leukocytosis in the postoperative period are essentially diagnostic of ischemic colitis. The complication can be prevented through careful selection of subjects that may require replanting inferior mesenteric artery (IMA) and completing the pre surgical procedure information with an instrumental evaluation during surgical treatment.

Pathophysiology

Colonic blood supply

The colon receives blood from both the superior and inferior mesenteric arteries. The blood supply from these two major arteries overlaps, with abundant collateral circulation via the

marginal artery of the colon In human anatomy, the marginal artery of the colon, also known as the marginal artery of Drummond, the artery of Drummond, and simply as the marginal artery, is an artery that connects the inferior mesenteric artery with the superior mesenteric ar ...

. However, there are weak points, or "watershed" areas, at the borders of the territory supplied by each of these arteries, such as the splenic flexure and the rectosigmoid junction. These watershed areas are most vulnerable to ischemia when blood flow decreases, as they have the fewest vascular collaterals. The rectum receives blood from both the inferior mesenteric artery and the

internal iliac artery The internal iliac artery (formerly known as the hypogastric artery) is the main artery of the pelvis. Structure The internal iliac artery supplies the walls and viscera of the pelvis, the buttock, the reproductive organs, and the medial compa ...

; the rectum is rarely involved by colonic ischemia due to this dual blood supply.

Development of ischemia

Under ordinary conditions, the colon receives between 10% and 35% of the total cardiac output.UpToDate, ''Colonic ischemia'', accessed 2 September 2006. If blood flow to the colon drops by more than about 50%, ischemia will develop. The arteries feeding the colon are very sensitive to vasoconstrictors; presumably this is an evolutionary adaptation to shunt blood away from the bowel and to the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

and

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

in times of stress. As a result, during periods of

, the arteries feeding the colon clamp down vigorously; a similar process can result from vasoconstricting drugs such as

ergotamine Ergotamine, sold under the brand names Cafergot (with caffeine) and Ergomar among others, is an ergopeptine and part of the ergot family of alkaloids; it is structurally and biochemically closely related to ergoline. It possesses structural sim ...

cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Ameri ...

, or vasopressors. This vasoconstriction can result in non-occlusive ischemic colitis.

Pathologic findings

A range of pathologic findings are seen in ischemic colitis, corresponding to the spectrum of clinical severity. In its mildest form, mucosal and submucosal

hemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, v ...

and edema are seen, possibly with mild necrosis or

ulceration An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...

. With more severe ischemia, a pathologic picture resembling inflammatory bowel disease (i.e. chronic ulcerations, crypt abscesses and pseudopolyps) may be seen. In the most severe cases, transmural infarction with resulting perforation may be seen; after recovery, the muscularis propria may be replaced by fibrous tissue, resulting in a stricture. Following restoration of normal blood flow,

reperfusion injury Reperfusion injury, sometimes called ischemia-reperfusion injury (IRI) or reoxygenation injury, is the tissue damage caused when blood supply returns to tissue ('' re-'' + ''perfusion'') after a period of ischemia or lack of oxygen (anoxia or hy ...

may also contribute to the damage to the colon.

Diagnosis

Ischemic colitis must be differentiated from the many other causes of

and rectal bleeding (for example,

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...

, 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 Intestinal ischemia is a medical condition in which injury to the large or small intestine occurs due to not enough blood supply. It can come on suddenly, known as acute intestinal ischemia, or gradually, known as chronic intestinal ischemia. The ...

of the

small bowel The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pa ...

. There are devices which test the sufficiency of oxygen delivery to the colon. The first device approved by the U.S. FDA in 2004 uses visible light spectroscopy to analyze capillary oxygen levels. Use during Aortic Aneurysm repair detected when colon oxygen levels fell below sustainable levels, allowing real-time repair. In several studies, Specificity has been 90% or higher for acute colonic ischemia, and 83% for chronic mesenteric ischemia, with a sensitivity of 71%-92%. This device must be placed using endoscopy, however.

Diagnostic tests

There is a recent optical test, but it requires endoscopy (see Diagnosis). There are no specific blood tests for ischemic colitis. The sensitivity of tests among 73 patients were: * The white blood cell count was more than 15,000/mm3 in 20 patients (27%) * The serum bicarbonate level was less than 24 mmol/L in 26 patients (36%) Plain

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

s are often normal or show non-specific findings. In a series of 73 patients, plain abdominal radiography (56%) showing colic distension in 53% or a pneumoperitoneum in 3%. CT scans are often used in the evaluation of abdominal pain and rectal bleeding, and may suggest the diagnosis of ischemic colitis, pick up complications, or suggest an alternate diagnosis.

Endoscopic An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are insert ...

evaluation, via colonoscopy or flexible

sigmoidoscopy Sigmoidoscopy (from the Greek term for letter " s/ς" + "eidos" + "scopy": namely, to look inside an "s"/"ς"-like object) is the minimally invasive medical examination of the large intestine from the rectum through to the nearest part of the co ...

, is the procedure of choice if the diagnosis remains unclear. Ischemic colitis has a distinctive endoscopic appearance; endoscopy can also facilitate alternate diagnoses such as

or inflammatory bowel disease.

Biopsies A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...

can be taken via endoscopy to provide more information. Visible light spectroscopy, performed using catheters placed through the 5 mm channel of the endoscope, is diagnostic (see Diagnosis).

Treatment

Except in the most severe cases, ischemic colitis is treated with supportive care.

IV fluids Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutri ...

are given to treat

, and the patient is placed on bowel rest (meaning nothing to eat or drink) until the symptoms resolve. If possible, cardiac function and oxygenation should be optimized to improve oxygen delivery to the ischemic bowel. A

nasogastric tube Nasogastric intubation is a medical process involving the insertion of a plastic tube (nasogastric tube or NG tube) through the nose, down the oesophagus, and down into the stomach. Orogastric intubation is a similar process involving the inserti ...

may be inserted if an

ileus Ileus is a disruption of the normal propulsive ability of the intestine. It can be caused by lack of peristalsis or by mechanical obstruction. The word 'ileus' is from Ancient Greek ''eileós'' (, "intestinal obstruction"). The term 'subileus' ref ...

is present. Antibiotics are sometimes given in moderate to severe cases; the data supporting this practice date to the 1950s, although there is more recent animal data suggesting that antibiotics may increase survival and prevent

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

from crossing the damaged lining of the colon into the bloodstream. The use of

prophylactic Preventive healthcare, or prophylaxis, consists of measures taken for the purposes of disease prevention.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental hea ...

antibiotics in ischemic colitis has not been prospectively evaluated in

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

s, but many authorities recommend their use based on the animal data. Patients being treated supportively are carefully monitored. If they develop worsening symptoms and signs such as high white blood cell count,

fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...

, worsened abdominal pain, or increased bleeding, then they may require surgical intervention; this usually consists of

laparotomy A laparotomy is a surgical procedure involving a surgical incision through the abdominal wall to gain access into the abdominal cavity. It is also known as a celiotomy. Origins and history The first successful laparotomy was performed without ane ...

and bowel resection.

Prognosis

Most patients with ischemic colitis recover fully, although the prognosis depends on the severity of the ischemia. Patients with pre-existing

peripheral vascular disease Peripheral artery disease (PAD) is an abnormal narrowing of arteries other than those that supply the heart or brain. When narrowing occurs in the heart, it is called coronary artery disease, and in the brain, it is called cerebrovascular dise ...

or ischemia of the ascending (right) colon may be at increased risk for complications or death. Non-gangrenous ischemic colitis, which comprises the vast majority of cases, is associated with a mortality rate of approximately 6%. However, the minority of patients who develop gangrene as a result of colonic ischemia have a mortality rate of 50–75% with surgical treatment; the mortality rate is almost 100% without surgical intervention.

Long-term complications

About 20% of patients with acute ischemic colitis may develop a long-term complication known as ''chronic ischemic colitis''. Symptoms can include recurrent infections, bloody diarrhea, weight loss, and chronic abdominal pain. Chronic ischemic colitis is often treated with surgical removal of the chronically diseased portion of the bowel. A '' colonic stricture'' is a band of scar tissue which forms as a result of the ischemic injury and narrows the lumen of the colon. Strictures are often treated observantly; they may heal spontaneously over 12–24 months. If a bowel obstruction develops as a result of the stricture, surgical resection is the usual treatment, although endoscopic dilatation and

stent In medicine, a stent is a metal or plastic tube inserted into the lumen of an anatomic vessel or duct to keep the passageway open, and stenting is the placement of a stent. A wide variety of stents are used for different purposes, from expandab ...

ing have also been employed.

Epidemiology

The exact incidence of ischemic colitis is difficult to estimate, as many patients with mild ischemia may not seek medical attention. Ischemic colitis is responsible for about 1 in 2000 hospital admissions and is seen on about 1 in 100 endoscopies.Feldman: Sleisenger & Fordtran's Gastrointestinal and Liver Disease, 7th ed., 2002 Saunders, p. 2332. Men and women are affected equally; ischemic colitis is a disease of the elderly, with more than 90% of cases occurring in people over the age of 60.

References

External links

{{Hemodynamics Colitis

Colitis Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification ...

Gastrointestinal tract disorders Diseases of intestines