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Colitis is the term used to described inflammation of the colon There are a variety of causes of colitis including infections, poor blood supply, and autoimmune reactions.
The colon (large bowel or large intestine) is responsible for collecting and storing the waste products of digestion. It is a long muscular tube that pushes undigested food towards the anus for eventual elimination as a bowel movement. As the liquid mixture of undigested food makes its journey, it mixes with mucus and normal bacteria residing in the colon. As well, water is reabsorbed into the bloodstream, and the feces start to solidify.
The colon is located in the abdominal cavity and is divided into the following parts: the cecum, the ascending colon, the transverse, the descending colon, the sigmoid, the rectum, and the anus. The right colon includes the cecum and ascending colon. The left colon includes the transverse segment to the sigmoid.
The wall of the colon has numerous layers. There is a smooth muscle layer that wraps the outside and is responsible for squeezing the undigested food through the length of the colon. The inner layers, or mucosa, come into contact with the fluid and allow water and electrolyte absorption to help solidify the feces. The mucosal layer is where the colon inflammation occurs and is responsible for the symptoms of colitis.
As with any other organ, the colon has a blood supply with arteries delivering oxygen rich blood and nutrients to it, and veins that drain carbon dioxide and lactic acid from it.
Inflammation of the colon can be caused by a variety of illnesses and infections. Some of the most common causes are discussed below.
Infectious Colitis
Viruses and bacteria can cause colon infections. Most are food-borne illnesses or "food poisoning." Common bacterial causes include Shigella, E.Coli, Salmonella and Campylobacter. These infections often present with bloody diarrhea and can cause significant dehydration.
Pseudomembranous colitis is caused by the bacteria Clostridium difficile (C. difficile). This disorder is often seen in patients who have recently been taking antibiotics for an infection. The antibiotic alters the normal bacteria present in the colon and allows an overgrowth of the Clostridium bacteria. Clostridium bacteria produce a toxin that causes diarrhea. This is an infection, and often there is a fever present. The diarrhea is usually not bloody.
Ischemic Colitis
The arteries that supply blood to the colon are like any other artery in the body. They have the potential to narrow due to atherosclerosis (just like blood vessels in the heart, which can cause angina, or narrowed vessels in the brain can cause a stroke). When these arteries narrow, the colon loses it's blood supply and becomes inflamed.
The colon can also lose its blood supply for mechanical reasons. A couple of examples include volvulus, in which the bowel twists on itself, or an incarcerated hernia in which a portion of the colon gets stuck in an outpouching of the abdominal wall.
In patients who are at risk for decreased blood flow to the colon, ischemic colitis can occur if the blood pressure falls. This may occur with dehydration, anemia, or shock.
Ischemia or lack of blood supply causes significant pain, fever, and bloody bowel movements.
Inflammatory Bowel Disease
There ate two types of inflammatory bowel disease. The first, ulcerative colitis, is thought to be an autoimmune illness in which the body's immune system attacks the colon and causes inflammation. Ulcerative colitis begins in the rectum and may gradually spread throughout the colon. The signs and symptoms are generally abdominal pain and bloody bowel movements.
Crohn's disease is the second type of inflammatory bowel disease, and may involve any part of the digestive tract from the esophagus and stomach to both the small and large intestine. It often has skip lesions, that is diseased areas are interspersed with healthy areas of tissue.
Microscopic Colitis
Two diseases make up this group of colon inflammation, collagenous colitis and lymphocytic colitis. In these diseases, the inflammation is caused by some layers of the colon wall becoming engorged with either collagen or lymphocytes. Watery, non-bloody diarrhea is the most common symptom.
This is an uncommon illness that is seen more frequently in older women. The cause is unknown but an auto-immune potential may exist.
Chemical Colitis
If chemicals are instilled into the colon, inflammation and damage can occur. One of the complications of an enema is the inflammation of the mucosal lining of the colon caused by harsh chemicals.
Symptoms of colitis will depend upon the type of colitis that is present, but in general, colitis most often is associated with abdominal pain and diarrhea.
Other symptoms may inlcude:
Diarrhea is a common symptom of colitis, and most episodes resolve in a matter of hours.
Medical care should be accessed if any of the following conditions exist:
As with most illnesses, the diagnosis begins with a thorough history by a physician or health care practitioner. Since the presenting complaint is usually abdominal pain and diarrhea, it is important to learn about the onset and duration of symptoms and any other complaints the patient may have. Since most causes of diarrhea are relatively benign and self-limiting, questions may be asked to search for some of the causes listed above.
An important concern is whether there is blood in the bowel movement. While this may lead to the diagnosis of colitis, colon cancer is another important cause of blood in the stool, and this symptom should not be ignored.
Some questions asked of the patient may include:
These may be within the digestive tract, like nausea or vomiting, or may be more general such as fever, chills, or other complaints.
Other questions may ask about lifestyle, especially if an infectious cause is being considered. Recent travel, unusual diet, or the use of noncommercial water (for example, drinking from a well or river water on a camping trip) may direct the diagnosis to illnesses like Shigella, Campylobacter or Yersinia bacterial infections. Recent use of antibiotics will be helpful to know.
The past medical history is also important to assess the risk factors for peripheral vascular disease or narrowing of the arteries. These include smoking, high blood pressure, high cholesterol, and diabetes. This may give direction to explore ischemic bowel as the cause for colitis.
Physical examination will focus on the abdomen. The physician will palpate or feel for areas of tenderness, for masses, or abnormally enlarged organs like the liver, spleen, and kidney.
While unpleasant, the rectal examination is of utmost importance. Using a finger, the physician feels inside the rectum, trying to find a mass or tumor. As well, the color and consistency of stool can be evaluated and if it is not grossly bloody, can be tested for occult blood (blood that is present but unable to be seen with the naked eye).
Vital signs are an important part of the physical examination. Temperature, blood pressure, pulse, and respiratory rate will help guide the direction of testing. If the vital signs are not stable, that is the blood pressure is low or the pulse rate too fast, a crisis may be imminent. The physician may need to intervene acutely and delay some of the diagnostic evaluation until the patient is stabilized.
Laboratory
Blood testing will help assess the stability of the patient and look for potential issues associated with colitis.
Colonoscopy
If the specific cause of colitis is not readily apparent, then colonoscopy may be considered. A gastroenterologist will insert a long flexible camera into the anus and examine the full length of the colon. The appearance of the colon by itself may be enough to make the diagnosis. Biopsies (small pieces of tissue) may be taken from the lining of the colon and examined by a pathologist (a medical doctor specializing in the diagnosis of tissues) to help confirm the diagnosis.
Colonoscopy is an essential cancer screening test and is especially important for those patients who have had blood in their stool that cannot be explained by another diagnosis.
Imaging
Computerized tomography (CT) may be used to image the colon and the rest of the abdomen. Different types of colitis have distinctive patterns that may help a radiologist recognize a specific diagnosis.
On occasion a barium enema or other imaging tests may be used to evaluate the anatomy of the colon.
If a person has bloody diarrhea, fever or intense pain, it is reasonable and appropriate to seek medical help by calling a health care practitioner or seeking care at a hospital emergency department.
The definitive treatment of colitis is dependent upon the cause. Many cases require little more than symptomatic care, including clear fluids to rest the bowel and medications to control pain. Some patients become acutely ill and will need intravenous fluids and other interventions to treat their illness.
Over-the-counter medications may be used for diarrhea and crampy abdominal pain; however, medical advice should be obtained if there is blood in the stool or the pain is intense. Loperamide (Imodium) is an effective medicine to control diarrhea. Acetaminophen or ibuprofen can be used for pain control.
Depending upon the cause of the colitis, medication may be prescribed to control or cure symptoms. Antibiotics may be helpful in colitis caused by some infections. Anti-inflammatory and immune suppression drugs can be used to control the symptoms of inflammatory bowel disease.
Surgery may be required for ischemic colitis, Crohn's disease, or ulcerative colitis, depending upon the severity of the illness and its response to more conservative non-surgical treatments.
In ulcerative colitis, removal of the colon cures the disease.
For other illnesses, usually the part of the colon that is at risk or damaged is removed.
For most patients, infectious colitis is an isolated event, and once the symptoms and infection have cleared, no further care is needed.
For those with inflammatory bowel disease, the goal becomes symptom control instead of disease cure, since symptoms can occur over the course of a lifetime. Once the initial diagnosis is made, continued care with a primary care provider and a gastroenterologist will be necessary. A long-term relationship with this treatment team may be able to lessen the frequency and intensity of future disease flare-ups.
Ischemic bowel disease does not happen in isolation, and a patient that has poor circulation to the bowel likely has poor circulation elsewhere. Continued monitoring may be necessary to minimize the risk of future episodes.
Infectious colitis remains a common ailment worldwide, affecting millions daily. The lack of clean drinking water and adequate sanitation are the main causes, leading to thousands of potentially preventable deaths each day. In developed countries, poor hand washing and poor kitchen hygiene allow the potential for infectious colitis. Prevention lies in cleanliness.
Inflammatory bowel diseases may be difficult to prevent at the present time. The likely causes are heredity and perhaps an abnormal auto-immune response to an unknown stimulus in the body.
Since ischemic colitis is caused by narrowing of the blood vessels to the bowel, decreasing the risks for other types of circulatory problems such as peripheral vascular disease, heart attack, and stroke will also decrease the risk for ischemic colitis. The common risk factors are smoking and poor control of high blood pressure, high cholesterol levels, and diabetes.
Understanding the cause of a specific colitis has allowed more targeted therapy. For example, observation has replaced surgery to remove the colon as standard therapy for some people with ulcerative colitis, and limiting the use of antibiotics has decreased the number of resistant bacteria that can cause infectious diarrhea.
Worldwide initiatives to increase access to clean water and adequate hygiene is perhaps the most important way to save lives.
ulcerative colitis, UC, colon, lining of colon, inflammation of colon, inflammatory bowel disease, IBD, Crohn disease, Crohn’s disease, colectomy, colonoscopy, colon cancer, dysplasia, ileitis, proctitis, radiation-associated colitis, ischemic colitis, antibiotic-associated colitis, ulcerative colitis, short-term colitis, colitis, C. difficile, infectious colitis, microscopic colitis, collagenous colitis, lymphocytic colitis, chemical colitis
Author: Benjamin C. Wedro, MD, FAAEM
Editor: Melissa Conrad Stöppler, MD
| © 2010 WebMD, LLC. All rights reserved. eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information. |
