Inflammatory bowel disease (IBD) is chronic inflammation of the digestive tract. Its cause is unknown. It appears to develop due to an overactive immune system that continues to attack healthy tissue after first being stimulated to fight a harmful substance. In patients with IBD, tissue lining the mouth, stomach, esophagus, intestines or anus can become red, swollen and bleed. Abdominal pain, cramping and bloody diarrhea are common IBD symptoms.
The two primary types of IBD are Crohn's disease (CD) and ulcerative colitis (UC). CD can occur anywhere along the digestive tract (most commonly in the small and/or large intestine), and irritate all layers of tissue in the wall lining. UC occurs only in the large intestine, usually starting in the rectum, and affects only the inner intestinal lining (colon mucosa).
Once it appears, IBD is a lifelong disease. It occurs primarily in the United States and Europe and among young people (10 to 35 years old) more often than in the elderly. Whites are at greater risk for IBD than non-whites, and people with Jewish ethnic backgrounds have a higher risk than non-Jews. Men and women appear to be at equal risk of developing IBD. Cigarette smokers are at higher risk of developing CD (but not UC). IBD also appears to run in families.
An initial physical examination may include a medical history, blood tests and stool tests. There are two primary methods used to diagnosis IBD. A barium x-ray involves ingesting a chalky liquid that helps organs show up clearly on x-rays. This can be used for examination of the upper digestive tract. The examination of the lower tract involves a barium enema or administration of the barium via a tube in the rectum. A colonoscopy involves inserting a small, flexible tube through the anus and into the colon. A light and camera record images for analysis by a physician. Biopsies and color photos can be taken during this procedure.
Complications of IBD include anemia (too few red blood cells), intestinal blockage or abscesses and an increased risk of colon cancer.
Long-term treatment is often required for patients with IBD. Medications such as aminosalicylates, corticosteroids and immunosuppressive therapy can help keep the symptoms of IBD in remission. Hospitalization may be required to treat patients with IBD who are severely malnourished, dehydrated or have experienced massive blood loss. Surgery may be necessary to treat cancer, when intestinal obstructions or perforations exist, or when medicines fail to work.
IBD is different from irritable bowel syndrome (IBS), which cannot be visually detected on diagnostic tests and does not include the symptoms of rectal bleeding, fever and elevated white blood cell count seen in patients with IBD.
About inflammatory bowel disease
Inflammatory bowel disease (IBD) is the chronic inflammation and irritation of tissue in the gastrointestinal tract. It can occur anywhere from the mouth to the anus, although it most often affects the intestines. When inflamed, the intestinal lining can become red, swollen, develop ulcers and bleed.
Patients with IBD may alternate between periods where symptoms are active and times when symptoms disappear (remission). Once it appears, IBD is a lifelong disease.
In severe cases, IBD can lead to other conditions, including dehydration (from diarrhea), anemia (from blood loss), ulcers, blockage or stricture of the intestinal passage and fistulae that can also lead to the formation of abscesses outside the intestine. Toxic megacolon (when the large intestine widens and loses muscle tone) can also occur. IBD may also increase a patient’s risk of developing colon cancer. In children the condition can cause retarded growth and delays in the onset of puberty.
The exact cause in unknown, but IBD appears to occur when intestinal cells, triggered to fight harmful substances in the digestive tract, continue to fight healthy intestinal lining. Protective cells that normally exist in the intestinal walls are activated to attack bacteria and viruses when they pass through the intestines. In patients with IBD, this fighting continues, even after the harmful substances have gone. This leads to the chronic inflammation and irritation of the intestines.
After food enters the mouth, it travels through the esophagus, stomach, small intestine (where most digestion occurs) and finally the large intestine, before waste is expelled through the anus. Any area along this route (called the alimentary canal) is subject to inflammation and irritation as a result of IBD.
In the small intestine (made up of the duodenum, jejunum and ileum), IBD most commonly affects the lowest area, the ileum. IBD can occur in all sections of the large intestine, including the cecum and rectum.
More than 1 million Americans have been diagnosed with IBD, according to the American College of Gastroenterology. There are 10 new cases for every 100,000 people each year.
Types and differences of IBD
Inflammatory bowel disease (IBD) is a chronic condition of inflammation or irritation that may occur in many different places throughout the digestive tract.
Some general terms are used to describe inflammation of the intestines. Colitis is the inflammation or irritation of the large intestine. Enteritis describes the same symptoms when they occur in the small intestine. Some types of inflammation are named for their cause. For example, radiation colitis or radiation enteritis is caused by radiation treatment received for various cancers of the abdomen. Infectious colitis or enteritis is caused by bacteria or viruses. The inflammation caused by ischemic colitis occurs when not enough oxygen-rich blood flows to the bowel.
The two primary types of IBD are Crohn's disease (CD) and ulcerative colitis (UC).
CD causes inflammation and ulceration anywhere in the digestive tract, from the mouth to the anus. Most commonly, it occurs in either the small intestine, large intestine or both. All layers of the intestinal lining can be affected. Inflammation may be confined to one location, or it may occur in various places, with normal areas between areas that are inflamed.
Various forms of CD are distinguished from one another by where in the digestive tract they occur. These include:
Ileocolitis. The most common form of CD, with symptoms occurring in both the small intestine’s ileum and the large intestine.
Ileitis. When inflammation occurs in the small intestine’s ileum.
Gastroduodenal CD. Affects the stomach and small intestine’s duodenum.
Jejunoileitis. Inflammation of the small intestine’s jejunum and ileum.
Crohn's colitis. Red, irritated tissue and inflammation that occurs in the colon only.
UC causes inflammation and ulceration only in the inner lining of the large intestine. In most cases, inflammation starts in the rectum and extends up the colon. UC may include various conditions that can occur throughout the large intestine. These conditions include:
Ulcerative proctitis. Inflammation occurs in the rectum and anus. It is a common and typically mild form of UC, but may be a precursor to more serious forms of UC.
Left-sided colitis (sometimes referred to as limited or distal colitis). Occurs along the left side, from the rectum into the colon.
Pancolitis. Affects the entire colon. Serious complications, such as intestinal perforation and massive bleeding, can result, requiring surgery.
Fulminant colitis. A rare but life-threatening condition that affects the entire colon, causing severe pain, diarrhea and abdominal distention. It may also cause toxic megacolon (severely distended colon) or colon rupture.
Additional conditions involving inflammation of the bowels include:
Microscopic colitis. Chronic inflammation in the colon. Named for the only method to view the inflammation – by examination of biopsied tissue under a microscope (affected areas appear normal during endoscopy). Symptoms start gradually and become long-term. They include chronic, watery diarrhea without blood (unlike both CD and UC), abdominal pain, cramping and dehydration. Microscopic colitis does not increase a patient’s risk of colon cancer.
Microscopic colitis includes:
Collagenous colitis. Where the lining of the colon develops a thick layer of non-elastic tissue made of a protein called collagen (connective tissue). Collagenous colitis develops primarily in women in their 50s and older.
Lymphocytic colitis. Where the lining of the colon accumulates lymphocytes (white blood cells that fight infection and disease). These cells may also appear in a patient with collagenous colitis.
Diversion colitis. Inflammation that affects the lower part of the large intestine (the part diverted from the digestive process) after surgery performed to remove the colon or rectum in order to alter the passage of stool through the bowels. These surgeries are sometimes performed to treat cancer, UC and diverticulitis. Symptoms usually appear within a year of surgery and include abdominal pain and blood or mucus in the stool. The symptoms are usually mild and do not require treatment. Reattaching the separated portions of the intestine can sometimes resolve the symptoms of diversion colitis.
Pseudomembranous colitis (also called necrotizing colitis). Occurs when the natural balance of bacteria in the intestines is disrupted, leading to inflammation and destruction of intestinal tissue. Antibiotics typically trigger this bacterial imbalance, although chemotherapy may also cause pseudomembranous colitis.
Necrotizing enterocolitis. Can occur in either the small or large intestine, although it most commonly affects the small intestine’s ileum. It is primarily a disease of infants, particularly premature or sick newborns, in which intestinal tissue dies and falls away from the intestinal wall. Although the cause is unknown, necrotizing enterocolitis appears to occur due to the bowel’s inability to produce enough protective mucus in the intestines. Bacteria may also play a role. Surgery is often required. According to the National Institutes of Health, approximately 25 percent of infants with necrotizing enterocolitis die of the disease.
IBD differs from irritable bowel syndrome (IBS) in both its diagnosis and symptoms. IBD is intestinal inflammation that can be seen via a barium x-ray or colonoscopy. IBS is a functional disorder – no inflammation is seen and IBS cannot be identified by diagnostic tests. Both involve symptoms of abdominal cramping and pain, as well as diarrhea. However, IBD can include rectal bleeding, fever and an elevated white blood cell count, whereas IBS does not.
Risk factors and causes of IBD
The cause of inflammatory bowel disease (IBD) is unknown. Since IBD appears to run in families, genetics and heredity may play a role. In fact, researchers resently linked the mutation of a specific gene to the development of Crohn’s disease (CD), a form of IBD. Another potential cause of IBD is the immune system. Patients with IBD experience an overreaction of their immune system. Once it is triggered to fight harmful substances, it appears unable to turn off. It continues to attack normal intestinal cells, leading to chronic inflammation and irritation. The cause of this problem is unknown, although infection, injury, dietary choices or environmental triggers may play a role.
Men and women appear to be at equal risk of developing IBD. However, there are a number of known risk factors, including:
Family history. Although estimates vary, somewhere between 10 to 30 percent of patients with IBD have a relative with the disease.
Age. Young people are more likely to develop IBD than older patients. Most often, IBD first appears between the ages of 10 to 35.
Race and ethnicity. Whites have a higher risk of developing IBD than non-whites. The risk of IBD is greater for people with a Jewish ethnic background, especially those of European descent, than other ethnic groups. IBD is a disease of the developed world, occurring primarily in the United States and Europe.
Cigarette smoking appears to have an effect on patients with IBD. The reason for this is not fully understood. However, IBD patients who smoke are more likely to have a more aggressive form of IBD than non-smokers. In addition, smokers are more likely to develop Crohn's disease than non-smokers. However, for ulcerative colitis (UC), the opposite is true – non-smokers are more likely to develop UC than smokers.
Signs and symptoms of IBD
The specific signs and symptoms of inflammatory bowel disease (IBD) include:
Diarrhea
Abdominal cramping
Abdominal pain
Rectal bleeding
Blood in the stool
Fever
Low red blood cell count (anemia)
Elevated white blood cell count
Loss of appetite
Unexplained weight loss
Urgency to have bowel movements
Other areas of the body may also be affected by IBD. Eyes may become swollen or red, and vision may become blurred. Sores in the mouth may appear. Joint pain can occur, with or without any accompanying swelling and redness. Skin rashes or sores may appear, particularly in the lower legs (e.g., erythema nodosum). In addition, research indicated that patients with IBD are at increased risk for carpal tunnel syndrome and other conditions that affect the nerves.
Diagnosis methods for IBD
Diagnosing inflammatory bowel disease (IBD) is a complex and lengthy process. The first step in diagnosing IBD is a visit to a physician for a medical history and physical examination. Patients may be asked about the duration of their symptoms, any family history of IBD and their cigarette smoking habits.
Blood and stool samples may also be required. Blood tests can identify low red blood cell counts (anemia), high white blood cell counts (inflammation or infection) and nutrient levels. A stool sample analysis can rule out intestinal infections, which include symptoms similar to IBD symptoms.
There are many other diseases and infections that can include symptoms similar to IBD. Through a variety of diagnostic tests, a physician may also want to rule out evidence of:
Ischemic colitis (inflammation that occurs when not enough oxygen-rich blood flows to the bowel)
Pelvic inflammatory disease
Ectopic pregnancy (when an embryo implants outside the uterus)
Ovarian cysts and tumors in women
Celiac disease
Tropical sprue
The two most common procedures used for diagnosing IBD are:
Barium x-ray. Organs are coated with a chalky substance (barium) that shows up on x-rays. With upper GI barium tests, patients drink the barium for x-rays of the esophagus, stomach and/or small intestine. With lower GI barium tests, barium is administered through an enema for x-rays of the large intestine. These x-rays allow physicians to identify any abnormalities within the digestive tract.
Colonoscopy. Examination using a small, flexible tube (with a light and camera) that is inserted into the anus and through the entire large intestine. This allows physicians to view the lining of the colon and identify the severity and extent of any disease. Patients are sedated during the procedure. A tissue sample may be taken for evaluation under a microscope (biopsy).
Additional diagnostic methods are sometimes used for patients with IBD. Computed axial tomography (CAT) scans are used to look for any sign of abdominal abscess that can result from IBD. An upper endoscopy may be used to identify abnormalities in the esophagus, stomach and first part of the small intestine. A new instrument, called a capsule endoscope, also allows physicians to look for abnormalities in the small intestine. Patients swallow a capsule that contains a tiny camera, which transmits images of the small intestine to a recorder for later viewing. This may be especially helpful for areas of the small intestine that are hard to reach during a conventional endoscopy, though the capsule should not be used in IBD patients with strictures because of concern regarding capsule passage.
Treatment and prevention of IBD
Inflammatory bowel disease (IBD) is a chronic condition that requires long-term treatment. There are a number of different medications that help treat the symptoms of IBD and keep the disease in remission. These include:
Aminosalicylates. Reduce inflammation in the intestinal wall. The active component of these drugs is a compound called 5-aminosalicylic acid (5-ASA) – the most common treatment choice for IBD. According to the American College of Gastroenterology (ACG), 5-ASA has been used to treat IBD for over 50 years. Aminosalicylates can be taken orally or rectally (in enema or suppository form). Side effects may include nausea, indigestion and/or headaches.
Corticosteroids. Used to control the inflammation of IBD when 5-ASA drugs do not work. This medication can be taken orally, rectally (e.g., as a suppository, enema) or intravenously (injected into a vein). Long-term use of corticosteroids can increase a patient’s risk of serious side effects, including high blood pressure, osteoporosis (a disorder in which the bones lose mass and density) and diabetes. Fluid retention and a rounded/swollen appearance of the face may also occur. However, side effects vary depending on the type of corticosteroid used.
Immunosuppressants. Suppresses the body’s ability to create the disease-fighting substances (antibodies) that attack the normal intestinal lining in IBD patients, causing inflammation. This decreases immune system activity in patients with IBD. Taken orally, these drugs may not take effect for weeks or months. Possible side effects include allergic reactions, pancreatitis, abnormal liver tests and an increased risk of infections. Newer medications are available in intravenous form.
Other medications can be used to help alleviate the symptoms of IBD, such as antidiarrheals, laxatives (in cases where intestinal obstruction or stricture leads to constipation), acetaminophen pain relievers, iron supplements and vitamin B12 injections (to help prevent anemia). Antibiotics may also be recommended to help kill harmful microorganisms in the intestines. Nonsteroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen) should not be used as they may intensify the symptoms of IBD.
Hospitalization may be necessary to treat patients with IBD when they are malnourished, or have experienced severe diarrhea and blood loss. A special diet may be required, along with intravenous feeding. Treatment will focus on avoiding further aggravation of the digestive tract.
Surgery may be required in cases of long-lasting illness, cancerous changes in the colon, intestinal obstruction or perforation, or when drug therapy is not working.
Up to 70 percent of IBD patients with Crohn's disease (CD) require surgery at some point in their lives, according to the (ACG). Many patients with CD experience inflammation that goes deep into the intestinal tissue – increasing their risk of fistulae, abscesses and intestinal strictures that can require surgery. However, surgery is not a cure for patients with CD. According to the ACG, the disease returns in 70 to 85 percent of patients with CD, even after surgery.
IBD patients with ulcerative colitis (UC), on the other hand, can cure the condition with surgery that removes the entire colon. When the large intestine is removed, the lower part of the small intestine (ileum) is connected directly to the anal region. In what is known as a pouch procedure, an internal pouch is created out of the ileum, eliminating the need for a permanent ostomy pouch (bag worn outside the body into which stool can drain).
For patients with CD, cigarette smoking can increase the number and severity of symptom flare-ups. Choosing not to smoke can decrease the severity of symptoms in patients with CD.
Proper nutrition is an important aspect of preventing or reducing the severity of IBD symptoms. A healthy diet for patients with IBD includes soft, bland foods that are low in fiber, as well as adequate amounts of proteins, calories and vitamins. Avoiding high-fiber foods (e.g., bran, beans, fresh fruits and vegetables), dairy products, caffeine and alcohol can help alleviate symptoms of IBD.
Chronic diarrhea may include a loss of control (fecal incontinence), which can be embarrassing and limit outdoor activities. Patients with IBD can be prepared for the sudden onset of symptoms by knowing the location of available restrooms when traveling, and by keeping extra toilet paper and clothing handy.
Managing stress levels may also help. Although there is little evidence to support stress as a cause of IBD, emotional stress may aggravate IBD symptoms.
Patients with IBD may experience isolation, anxiety and embarrassment as a result of their recurring symptoms. Because of this, attending IBD support groups can provide emotional support from others also living with the disease. If patients become depressed as a result of their IBD, they may want to seek the help of a mental health professional.
Questions for your doctor about IBD
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to inflammatory bowel disease (IBD):
I have diarrhea that is occasionally bloody. Do I have IBD?
What kind of tests will you need to perform to know for sure?
Could my symptoms be a sign of something besides IBD?
If I’m diagnosed with IBD, does that mean I have Crohn’s disease or ulcerative colitis? What’s the difference between the two? Could I have another type of inflammatory condition or disease?
Where exactly is the inflammation in my body?
Is something I’m eating or drinking causing my IBD or aggravating its symptoms? What about smoking? Or stress?
What type of treatment do you recommend?
What medication is most appropriate for me? How long will I have to take it? Are there over-the-counter medications I can also take that would help?
Are there any over-the-counter medications I should avoid?
Will I need surgery? What are the risks and benefits of surgery, given the extent and severity of my IBD?
What lifestyle changes do you recommend to accommodate my IBD?
