Intestinal ischemia is a medical condition in which injury to the

large Large means of great size. Large may also refer to: Mathematics * Arbitrarily large, a phrase in mathematics * Large cardinal, a property of certain transfinite numbers * Large category, a category with a proper class of objects and morphisms ...

small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...

occurs due to not enough

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

supply. It can come on suddenly, known as acute intestinal ischemia, or gradually, known as chronic intestinal ischemia. The acute form of the disease often presents with sudden severe abdominal pain and is associated with a high risk of death. The chronic form typically presents more gradually with

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 ...

after eating, unintentional weight loss,

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenter ...

, and fear of eating. Risk factors for acute intestinal ischemia include atrial fibrillation,

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

chronic kidney failure Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, v ...

, being prone to forming blood clots, and previous

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 ma ...

. There are four mechanisms by which poor blood flow occurs: a blood clot from elsewhere getting lodged in an artery, a new blood clot forming in an artery, a blood clot forming in the

superior mesenteric vein In human anatomy, the superior mesenteric vein (SMV) is a blood vessel that drains blood from the small intestine (jejunum and ileum). Behind the neck of the pancreas, the superior mesenteric vein combines with the splenic vein to form the hepa ...

, and insufficient blood flow due to

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 spasms of arteries. Chronic disease is a risk factor for acute disease. The best method of diagnosis is

angiography Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is perfor ...

, with computed tomography (CT) being used when that is not available. Treatment of acute ischemia may include

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 or medications to break down the clot provided at the site of obstruction by

interventional radiology Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs b ...

Open surgery Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definiti ...

may also be used to remove or bypass the obstruction and may be required to remove any intestines that may have died. If not rapidly treated outcomes are often poor. Among those affected even with treatment the risk of death is 70% to 90%. In those with chronic disease

bypass surgery Bypass surgery refers to a class of surgery involving rerouting a tubular body part. Types include: * Vascular bypass surgery such as coronary artery bypass surgery, a heart operation * Cardiopulmonary bypass, a technique used in coronary artery ...

is the treatment of choice. Those who have thrombosis of the vein may be treated with

anticoagulation Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...

such as

heparin Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Since heparins depend on the activity of antithrombin, they are considered anticoagulants. Specifically it is also used in the treat ...

and

warfarin Warfarin, sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent st ...

, with surgery used if they do not improve. Acute intestinal ischemia affects about five per hundred thousand people per year in the developed world. Chronic intestinal ischemia affects about one per hundred thousand people. Most people affected are over 60 years old. Rates are about equal in males and females of the same age. Intestinal ischemia was first described in 1895.

Signs and symptoms

While not always present and often overlapping, three progressive phases of intestinal ischemia have been described: * A ''hyper active'' stage 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 emerge ...

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

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 ...

Clinical findings

Symptoms of intestinal ischemia vary and can be acute (especially if embolic), subacute, or chronic. Case series report prevalence of clinical findings and provide the best available, yet biased, estimate of the sensitivity of clinical findings. In a series of 58 patients with intestinal ischemia due to mixed causes: *

was present in 95% (median of 24 hours duration). The other three patients presented with shock and

. *

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...

in 44% *

in 35% *

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

in 35% *

heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

> 100 in 33% *

rectal bleeding Rectal bleeding refers to bleeding in the rectum. There are many causes of rectal hemorrhage, including inflamed hemorrhoids (which are dilated vessels in the perianal fat pads), rectal varices, proctitis (of various causes), stercoral ulcers and ...

in 16% (not stated if this number also included occult blood – presumably not) *

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel moveme ...

in 7%

Diagnostic heuristics

In the absence of adequate quantitative studies to guide diagnosis, various heuristics help guide diagnosis: * Intestinal ischemia" should be suspected when individuals, especially those at high risk for acute intestinal ischemia, develop severe and persisting abdominal pain that is disproportionate to their abdominal findings"., or simply, pain out of proportion to exam. * Regarding intestinal arterial thrombosis or embolism: "early symptoms are present and are relative mild in 50% of cases for three to four days before medical attention is sought". * Regarding intestinal arterial thrombosis or embolism: "Any patient with an arrhythmia such as atrial fibrillation who complains of abdominal pain is highly suspected of having embolization to the superior mesenteric artery until proved otherwise." * Regarding nonocclusive intestinal ischemia: "Any patient who takes digitalis and diuretics and who complains of abdominal pain must be considered to have nonocclusive ischemia until proved otherwise."

Diagnosis

It is difficult to diagnose intestinal ischemia early.

Blood tests

In a series of 58 patients with intestinal ischemia due to mixed causes: *

White blood cell count A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and ...

>10.5 in 98% (probably an overestimate as only tested in 81% of patients) *

Lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as nat ...

elevated 91% (probably an overestimate as only tested in 57% of patients) In very early or very extensive acute intestinal ischemia, elevated lactate and white blood cell count may not yet be present. In extensive mesenteric ischemia, bowel may be ischemic but separated from the blood flow such that the byproducts of ischemia are not yet circulating.

During endoscopy

A number of devices have been used to assess the sufficiency of oxygen delivery to the colon. The earliest devices were based on tonometry, and required time to equilibrate and estimate the pHi, roughly an estimate of local CO₂ levels. The first device approved by the U.S. FDA (in 2004) used 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 83% for chronic intestinal ischemia and 90% or higher for acute colonic ischemia, with a sensitivity of 71%-92%. This device must be placed using endoscopy, however. Findings on gastroscopy may include edematous gastric mucosa, and hyperperistalsis. Finding on colonoscopy may include: fragile mucosa, segmental erythema, longitudinal ulcer, and loss of haustrations

Plain X-ray

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.

Computed tomography

Computed tomography (CT scan) is often used. The accuracy of the CT scan depends on whether a small bowel obstruction (SBO) is present. SBO absent * prevalence of intestinal ischemia 23% * sensitivity 64% * specificity 92% *

positive predictive value The positive and negative predictive values (PPV and NPV respectively) are the proportions of positive and negative results in statistics and diagnostic tests that are true positive and true negative results, respectively. The PPV and NPV des ...

(at prevalence of 23%) 79% *

negative predictive value The positive and negative predictive values (PPV and NPV respectively) are the proportions of positive and negative results in statistics and diagnostic tests that are true positive and true negative results, respectively. The PPV and NPV des ...

(at prevalence of 23%) 95% SBO present * prevalence of intestinal ischemia 62% * sensitivity 83% * specificity 93% *

(at prevalence of 62%) 93% *

(at prevalence of 62%) 61% Early findings on CT scan include: * Intestinal mesenteric edema * Bowel dilatation * Bowel wall thickening * Intestinal mesenteric stranding * Evidence of adjacent solid organ infarctions to the kidney or spleen, consistent with a cardiac embolic shower phenomenon In embolic acute intestinal ischemia, CT-Angiography can be of great value for diagnosis and treatment. It may reveal the emboli itself lodged in the superior mesenteric artery, as well as the presence or absence of distal mesenteric branches. Late findings, which indicate dead bowel, include: * Intramural bowel gas * Portal venous gas * Free abdominal air

Angiography

As the cause of the ischemia can be due to embolic or thrombotic occlusion of the mesenteric vessels or nonocclusive ischemia, the best way to differentiate between the etiologies is through the use of mesenteric angiography. Though it has serious risks, angiography provides the possibility of direct infusion of vasodilators in the setting of nonocclusive ischemia.

Treatment

The treatment of intestinal ischemia depends on the cause and can be medical or surgical. However, if bowel has become necrotic, the only treatment is surgical removal of the dead segments of bowel. In non-occlusive disease, where there is no blockage of the arteries supplying the bowel, the treatment is medical rather than surgical. People are admitted to the hospital for resuscitation with intravenous fluids, careful monitoring of laboratory tests, and optimization of their cardiovascular function. NG tube decompression and heparin anticoagulation may also be used to limit stress on the bowel and optimize perfusion, respectively. Surgical revascularisation remains the treatment of choice for intestinal ischaemia related to an occlusion of the vessels supplying the bowel, but thrombolytic medical treatment and vascular interventional radiological techniques have a growing role. If the ischemia has progressed to the point that the affected intestinal segments are

gangrenous Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the gan ...

, a

bowel resection A bowel resection or enterectomy ('' enter-'' + '' -ectomy'') is a surgical procedure in which a part of an intestine (bowel) is removed, from either the small intestine or large intestine. Often the word ''enterectomy'' is reserved for the sense ...

of those segments is called for. Often, obviously dead segments are removed at the first operation, and a second-look operation is planned to assess segments that are borderline that may be savable after revascularization.

Methods for revascularization

* Open surgical thrombectomy * Intestinal bypass * Trans-femoral antegrade intestinal angioplasty and stenting * Open retrograde intestinal angioplasty stenting * Trans-catheter thrombolysis

Prognosis

The prognosis depends on prompt diagnosis (less than 12–24 hours and before gangrene) and the underlying cause: * venous thrombosis: 32% mortality * arterial embolism: 54% mortality * arterial thrombosis: 77% mortality * non-occlusive ischemia: 73% mortality. In the case of prompt diagnosis and therapy, acute intestinal ischemia can be reversible.

History

Acute intestinal ischemia was first described in 1895 while chronic disease was first described in the 1940s. Chronic disease was initially known as angina abdominis.

Terminology

The related term mesenteric ischemia generally defined as ischemia of the small bowel specifically. It has also been defined as poor circulation in the vessels supplying blood flow to any or several of the mesenteric organs, including the stomach, liver, colon and intestine.

In the large intestine

Ischemia of the

large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before bein ...

(colon) is termed

ischemic colitis 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 ...

. Although uncommon in the general population, ischemic colitis occurs with greater frequency in the elderly, and is the most common form of

bowel 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. Th ...

. 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.

) 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 cr ...

. In most cases, no specific cause can be identified.Feldman: Sleisenger & Fordtran's Gastrointestinal and Liver Disease, 7th ed., 2002 Saunders, p. 2332. 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 Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the gan ...

, 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 Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...

and

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

stricture Stricture may refer to: * stricture (medicine), a narrowing of a tubular structure,. ** esophageal stricture A benign esophageal stricture, or peptic stricture, is a narrowing or tightening of the esophagus that causes swallowing difficulties. ...

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 ...

References

External links

{{Hemodynamics Diseases of intestines Ischemia Wikipedia medicine articles ready to translate Wikipedia emergency medicine articles ready to translate