What is Colitis?
Simply put, Colitis is swelling (inflammation) of the large intestine (colon). In medicine, colitis refers to an inflammation of the colon and is often used to describe an inflammation of the large intestine (colon, caecum and rectum).
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 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. Food is digested in the stomach into a liquid slurry that passes through the small intestine where the nutrients are absorbed into the body for use. When the liquid mixture enters the colon, it mixes with mucus and normal bacteria that reside in the colon. 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 layer, or mucosa, comes into contact with the fluid and allows the absorption of water and electrolytes, which helps to solidify the feces (poop). 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. Diseases that decrease blood supply can cause inflammation of the colon.
What causes colitis?
Many theories exist about what causes colitis. People with colitis have abnormalities of the immune system, but doctors do not know whether these abnormalities are a cause or a result of the disease. The body’s immune system is believed to react abnormally to the bacteria in the digestive tract.
Colitis is not caused by emotional distress or sensitivity to certain foods or food products, but these factors may trigger symptoms in some people. The stress of living with ulcerative colitis may also contribute to a worsening of symptoms.
Is colon cancer a concern?
Colorectal Cancer About 5 percent of people with ulcerative colitis develop colon cancer. The risk of cancer increases with the duration of the disease and how much the colon has been damaged. For example, if only the lower colon and rectum are involved, the risk of cancer is no higher than normal. However, if the entire colon is involved, the risk of cancer may be as much as 32 times the normal rate.
Sometimes precancerous changes occur in the cells lining the colon. These changes are called “dysplasia.” People who have dysplasia are more likely to develop cancer than those who do not. Doctors look for signs of dysplasia when doing a colonoscopy or sigmoidoscopy and when examining tissue removed during these tests. According to the 2002 updated guidelines for colon cancer screening, people who have had IBD throughout their colon for at least 8 years and those who have had IBD in only the left colon for 12 to 15 years should have a colonoscopy with biopsies every 1 to 2 years to check for dysplasia. Such screening has not been proven to reduce the risk of colon cancer, but it may help identify cancer early.
These guidelines were produced by an independent expert panel and endorsed by numerous organizations, including the American Cancer Society, the American College of Gastroenterology, the American Society of Colon and Rectal Surgeons, and the Crohn’s & Colitis Foundation of America.
Diagnosis – How is ulcerative colitis diagnosed?
Many tests are used to diagnose ulcerative colitis. A physical exam and medical history are usually the first step.
Blood tests may be done to check for anemia, which could indicate bleeding in the colon or rectum, or they may uncover a high white blood cell count, which is a sign of inflammation somewhere in the body.
A stool sample can also reveal white blood cells, whose presence indicates ulcerative colitis or inflammatory disease. In addition, a stool sample allows the doctor to detect bleeding or infection in the colon or rectum caused by bacteria, a virus, or parasites.
A colonoscopy or sigmoidoscopy are the most accurate methods for making a diagnosis of ulcerative colitis and ruling-out other possible conditions, such as Crohn’s disease, diverticular disease, or cancer. For both tests, the doctor inserts an endoscope-a long, flexible, lighted tube connected to a computer and TV monitor-into the anus to see the inside of the colon and rectum. The doctor will be able to see any inflammation, bleeding, or ulcers on the colon wall. During the exam, the doctor may do a biopsy, which involves taking a sample of tissue from the lining of the colon to view with a microscope.
Sometimes x rays such as a barium enema or CT scans are also used to diagnose ulcerative colitis or its complications.
What are the symptoms of colitis?
The signs and symptoms of colitis are quite variable and dependent on the etiology (or cause) of the given colitis and factors that modify its course and severity.
Symptom of colitis may include: abdominal pain, loss of appetite, fatigue, diarrhea, cramping, urgency (tenesmus) and bloating. Signs may include: abdominal tenderness, weight loss, changes in bowel habits (increased frequency), fever, bleeding (overt or occult)/bloody stools, diarrhea and distension.
Signs seen on colonoscopy include: colonic mucosal erythema (redness of the inner surface of the colon), ulcers, bleeding.
What is the treatment for ulcerative colitis?
How a given colitis is treated is dependent on its etiology, e.g. infectious colitis are usually treated with antimicrobial agents (e.g. antibiotics); autoimmune mediated colitis is treated with immune modulators/immune suppressants. Severe colitis can be life-threatening and may require surgery.
Occasionally, symptoms are severe enough that a person must be hospitalized. For example, a person may have severe bleeding or severe diarrhea that causes dehydration. In such cases the doctor will try to stop diarrhea and loss of blood, fluids, and mineral salts. The patient may need a special diet, feeding through a vein, medications, or sometimes surgery.
About 25 to 40 percent of ulcerative colitis patients must eventually have their colons removed because of massive bleeding, severe illness, rupture of the colon, or risk of cancer. Sometimes the doctor will recommend removing the colon if medical treatment fails or if the side effects of corticosteroids or other drugs threaten the patient’s health.
Surgery to remove the colon and rectum, known as proctocolectomy, is followed by one of the following:
- Ileostomy, in which the surgeon creates a small opening in the abdomen, called a stoma, and attaches the end of the small intestine, called the ileum, to it. Waste will travel through the small intestine and exit the body through the stoma. The stoma is about the size of a quarter and is usually located in the lower right part of the abdomen near the beltline. A pouch is worn over the opening to collect waste, and the patient empties the pouch as needed.
- Ileoanal anastomosis, or pull-through operation, which allows the patient to have normal bowel movements because it preserves part of the anus. In this operation, the surgeon removes the colon and the inside of the rectum, leaving the outer muscles of the rectum. The surgeon then attaches the ileum to the inside of the rectum and the anus, creating a pouch. Waste is stored in the pouch and passes through the anus in the usual manner. Bowel movements may be more frequent and watery than before the procedure. Inflammation of the pouch (pouchitis) is a possible complication.
Not every operation is appropriate for every person. Which surgery to have depends on the severity of the disease and the patient’s needs, expectations, and lifestyle. People faced with this decision should get as much information as possible by talking to their doctors, to nurses who work with colon surgery patients (enterostomal therapists), and to other colon surgery patients. Patient advocacy organizations can direct people to support groups and other information resources.
What are the different types of colitis?
There are many types of colitis. They are usually classified by the etiology. Types of colitis include:
- Inflammatory bowel disease (IBD) – a group of chronic colitides. Main article: Inflammatory bowel disease
- Ulcerative colitis – a chronic colitis that affects the large intestine.
- Crohn’s disease – a type of IBD often leads to a colitis.
- Microscopic colitis – a colitis is diagnosed by microscopic examination of colonic tissue; macroscopically it is normal appearing.
- Lymphocytic colitis.
- Collagenous colitis.
- Diversion colitis.
- Chemical colitis.
- Ischemic colitis.
- Infectious colitis.
A well-known subtype of infectious colitis is pseudomembranous colitis, which results from infection by a toxigenic (produces toxins) strain of Clostridium difficile (c-diff).
Entero hemorrhagic colitis may be caused by Shiga toxin in Shigella dysenteriae or Shigatoxigenic group of Escherichia coli (STEC), which includes serotype O157:H7 and other enterohemorrhagic E. coli.
Parasitic infections, like those caused by Entamoeba histolytica, can also cause colitis.
Indeterminate colitis is a term used for a colitis that has features of both Crohn’s disease and ulcerative colitis. Indeterminate colitis’ behaviour is usually closer to ulcerative colitis than Crohn’s disease.
Atypical colitis is a phrase that is occasionally used by physicians for a colitis that does not conform to criteria for accepted types of colitis. It is not an accepted diagnosis per se and, as such, a colitis that cannot be definitively classified.
Severity of colitides
Fulminant colitis is any colitis that becomes worse rapidly. In addition to the diarrhea, fever, and anemia seen in colitis, the patient has severe abdominal pain and presents a clinical picture similar to that of septicemia, where shock is present. About half of human patients require surgery. In horses, the fulminant colitis known as colitis X usually results in death within 24 hours.
Irritable bowel syndrome, a separate disease, has been called spastic colitis. This name may lead to confusion, since colitis is not always a feature of irritable bowel syndrome. Since the etiology of IBS is currently unknown and possibly multifactorial, there may be some overlap in symptoms between IBS and the various forms of colitis.