Abdominal pain is one of the most common gastrointestinal symptoms, and it is something virtually everyone experiences at some point during their lives. It may range from mild to severe and can be felt all over or just in a particular section of the abdomen. Because of how common it is, it can sometimes be hard for doctors to determine a cause. One potential but relatively rare reason for abdominal pain is intestinal ischemia, a condition that can occur in the small intestine but is more likely to present in the large intestine.

Overview of Ischemic Colitis

Ischemic colitis (also sometimes spelled ischaemic colitis) is the most common subtype of ischemic bowel disease, and it is characterized by reduced blood flow to the large intestine. This reduced blood flow deprives the colon of oxygen and nutrients, which typically results in inflammation of or damage to the mucosal inner lining. Anyone can get ischemic colitis, though it is much more likely in people over the age of 60 and anyone with a history of arterial disease. While acute cases generally heal on their own, chronic ischemic colitis can cause tissue death (gangrene) and a variety of life-threatening complications.

Most of the small bowel, large bowel, and rectum are supplied with blood by the superior mesenteric artery and the inferior mesenteric artery. There are several “watershed” areas in this area of the gastrointestinal system (ie. splenic flexure) that are prone to ischemia because of a tendency in about half the population to have underdeveloped mesenteric arteries. Blood pressure and blood flow may fluctuate in any person, but ischemia becomes a factor when there has been at least a 75% reduction in flow for 12 hours or more.

Symptoms of Ischemic Colitis

Depending on the severity and extent of the disruption in blood flow, ischemic colitis can present with a range of symptoms. Like its small intestine counterpart (acute mesenteric ischemia), ischemic colitis is sometimes misdiagnosed because the symptoms can easily be confused with a number of other gastrointestinal problems. Below are some of the common symptoms:

  • Abdominal pain: The most common symptom is abdominal pain or cramping that is typically localized to the lower left side of the abdomen. The pain can build over time or occur suddenly; it may also worsen after eating.
  • Diarrhea: Diarrhea is another common symptom of ischemic colitis; in more severe cases blood diarrhea can occur and can indicate injury or damage to the intestinal mucosa.
  • Rectal bleeding: In addition to blood being found in the stool, ischemic colitis can also lead to separate rectal bleeding. The blood may be bright red or dark red depending on the severity of bleeding (hemorrhage).
  • Bowel urgency: Some people with ischemic colitis may experience a sudden and urgent need to have a bowel movement.
  • Nausea and vomiting: The combination of pain and disruption to the gastrointestinal system can also sometimes cause nausea and vomiting.
  • Fever: Fever may occur if there is significant inflammation or an infection associated with ischemic colitis.

What Causes Ischemic Colitis?

As noted earlier, the mechanism of ischemic colitis is reduced blood flow to the blood vessels of the large intestine. There are a variety of risk factors that can make this more likely, including advanced age, smoking, being obese, high blood pressure, or having a history of cardiovascular disease. Additionally, there are some medical conditions that can impact intestinal blood flow and also increase the chance of developing ischemia:

  • Atherosclerosis: One of the most basic risk factors of ischemic colitis is atherosclerosis, the narrowing or blockage of arteries. In this case, the arteries that supply the colon with blood can become narrow or blocked due to the buildup of fatty deposits (plaque) on the arterial walls.
  • Blood clots: Closely related to atherosclerosis, blood clots (vascular occlusion) are another possible cause of reduced blood flow. A blood clot (venous thrombosis when in a vein) or an embolism can block the flow of blood in the arteries of the digestive system.
  • Vasculitis: Vasculitis is a condition that involves the inflammation of blood vessels; in addition to causing damage to the vessels themselves, vasculitis can also lead to narrowing that can impede blood flow to the intestines.
  • Hypoperfusion: Perfusion refers to the passage of blood between the circulatory system and organs around the body, and hypoperfusion in the digestive system means that not enough blood is meeting the metabolic needs of relevant cells. Conditions like shock, hypotension, and heart failure can all potentially lead to hypoperfusion and thus ischemic colitis.
  • Inflammatory bowel disease: Inflammatory bowel disease (principally Crohn’s disease and ulcerative colitis), as the name implies, is characterized by inflammation in the small or large intestine. This generally can create a predisposition to ischemic colitis because of how inflammation impacts the bowels. Irritable bowel syndrome can have a similar effect for similar reasons.
  • Peripheral vascular disease: While peripheral vascular disease usually refers to the abnormal narrowing of arteries in any blood vessel outside the heart and brain, it mostly involves the legs. But this can also increase the chances of narrowing in the vessels of the digestive system as well.

Potential Complications

For many people, ischemic colitis is a temporary condition that can heal on its own and isn’t a major area of concern. In some circumstances, however, leaving it untreated can lead to various complications that can range from mild to life-threatening. Below are some of the most common complications of ischemic colitis:

  • Gangrene: If the reduction of blood flow lasts long enough, the tissues being fed by that blood supply can be subject to necrosis and eventual tissue death.
  • Bowel perforation: With prolonged ischemia and tissue damage, the walls of the bowels can weaken. In some cases this can result in a perforation of the bowels. Once perforated, intestinal contents can then leak into the abdominal cavity and cause sepsis, peritonitis, pneumatosis, or the formation of an abscess.
  • Stricture: Repeated incidence of ischemic colitis can eventually cause the formation of scar tissue in the colon; this can then lead to a stricture and a permanent narrowing of the intestinal passage. Such a stricture can even cause a bowel obstruction that prevents the normal passage of stool. Resulting symptoms include abdominal pain, constipation, and distension.

Diagnosis and Treatment

Because the symptoms are so similar to other conditions, the diagnosis of ischemic colitis typically involves a combination of medical history review, physical examination, and diagnostic tests. Examples of tests that might be used are blood tests, CT scan, colonoscopy (usually a flexible sigmoidoscopy), endoscopy, or biopsy. In cases where the cause is unclear or if there is suspicion of vascular abnormalities, angiography may be performed to evaluate blood flow within the mesenteric arteries and identify areas of stenosis or occlusion.

Treatment for ischemic colitis is dependent on the severity of the condition as well as whether or not the condition persists. Below are some common treatment options:

  • Supportive care: Mild cases may be resolved with supportive measures like ingesting nutrients intravenously in order to rest the bowels and maintain hydration.
  • Medication: Various medications can be used to either treat the underlying condition that led to the narrowing of the bowels or manage the symptoms. Antibiotics, anticoagulants, or antiplatelet agents are all possible options.
  • Surgery: For the most severe cases, especially where bowel perforation or necrosis has occurred, surgery may be another option. In such cases, resection is often used to remove the part of the bowel that has been affected by the reduced blood flow. Stenting can also be used to reopen or widen blood vessels.

Contact Cary Gastroenterology For Digestive Healthcare

While ischemic colitis is relatively rare, it can be a serious problem that requires medical attention; in fact, the mortality rate for patients who require surgery is up to 54%. If you have been experiencing any of the symptoms noted above, it may be time to get checked out by a gastroenterologist. Please contact our highly qualified team at Cary Gastro to request an appointment.