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Disease Basics
IBD: Overview
Potential Causes of IBD How Is IBD Diagnosed? What Is Ulcerative Colitis? Symptoms of Ulcerative Colitis What Is Crohn’s Disease? Symptoms of Crohn’s Disease Managing IBD Treating IBD Ulcerative Colitis and Surgery Crohn’s Disease and Surgery Inflammatory bowel disease (IBD) is a fairly common condition. It is estimated that more than one million people in the United States have IBD. The number of IBD patients is split equally between those with Crohn's disease (Crohn's) and those with ulcerative colitis (UC). The incidence of ulcerative colitis has remained steady (2 to 6 per 100,000 people), whereas the incidence of Crohn's has been increasing. About one-third of cases present in the second decade of life, with the peak incidence between 10 and 30 years of age, although very young children (2 percent of cases) do occasionally develop IBD. Studies also show an increased incidence in the elderly between ages 50 and 80. Women appear just slightly more likely to develop Crohn's than men. Some studies suggest men develop ulcerative colitis at slightly higher rates than women. However, these estimates are based on studies in selected communities and may not be representative of the occurrence of IBD in the country as a whole. IBD patients account for nearly three-quarters of a million physician visits per year and are often hospitalized. Crohn's accounts for approximately two-thirds of these visits/hospitalizations (there are an estimated 20,000 hospitalizations and 250,000 physician visits for ulcerative colitis yearly), although these figures may change as use of outpatient treatment becomes more sophisticated with the more frequent use of such interventions as intravenous medications. Most of the hospitalizations for IBD involve surgery. Only 20 percent of ulcerative colitis patients in the United States undergo surgery; 50 to 80 percent of Crohn's patients will eventually require surgery to repair some complication, such as obstruction, hemorrhage, fistulization or refractory disease. These conditions usually occur in discrete flares with periods of inactivity, and, inasmuch as they cannot be cured, they are best managed with a maintenance strategy to minimize symptoms, prevent complications and avoid premature mortality. IBD includes ulcerative colitis and Crohn's Disease, two different and distinct diseases. There are people with definite Crohn's Disease and others with definite ulcerative colitis. Occasionally, however, (as often as 5 to 15 percent of the time) a thorough medical evaluation still does not indicate a clear diagnosis. Those in whom a diagnosis is uncertain or cannot be determined are considered to have "indeterminate colitis." Occasionally, even when a diagnosis appears definite, the final diagnosis can change. 
The current understanding of both Crohn's Disease and ulcerative colitis identifies three factors, which interact to cause the development of these diseases in an individual:
Research is rapidly increasing our understanding of the specific details for each of these areas, which contribute to the development of IBD, though much remains undetected. A number of environmental factors have been identified, but others remain unknown. One gene in which a defect is a known risk for Crohn's Disease has been identified. An intensive search continues for others. Genetics, environment and the immune system contribute differently in each patient. The part each plays and the nature of its influence is a determining factor for the disease:
While the cause of IBD is still unknown, many lines of research suggest that it may result either from an abnormal response by the body's immune system to normal intestinal bacteria, or from immune responses to disease-causing bacteria or viruses.
No one test alone clearly forms a diagnosis of Crohn's or ulcerative colitis. Instead, a variety of approaches and studies are necessary to get a complete picture. The first step to diagnose and determine appropriate therapy for any disease is for competent medical personnel to learn the patient's medical history in detail. In seeking a healthcare provider, even if it is the first time, it is worth taking time to consider some important details to be able to explain them clearly:
A variety of X-ray tests can help doctors see more completely and assess what is abnormal. The two most common tests are the upper GI series and the barium enema. In the upper GI series, the patient swallows a liquid containing barium, and then X-rays are taken as it passes through the stomach and small intestine. To view the colon, doctors use the barium enema to pass barium up into the colon and then examine it with X-rays. These will help guide the diagnosis and therapy. Inspection of the lining of the colon with colonoscopy (passing a tube with a video camera up into the colon through the rectum) can look throughout the colon and the last part of the small bowel (known as the terminal ileum). With an endoscopic tube passed through the mouth, doctors can look at the esophagus (swallowing tube), stomach, the duodenum (the first part of the small ) and just beyond the capsule endoscopy duodenum. Using these types of endoscopy, doctors cannot only see the inside of the intestines, but they can also biopsy the tissues for examination under a microscope. Capsule endoscopy (swallowing a pill with a camera in it that transmits pictures by radio waves to a receiver worn in a belt) permits most of the small bowel to be inspected. This is not a yet a fully acceptable method to evaluate the esophagus and stomach. It is also not useful in looking at the colon. In addition, biopsies or tissue sampling cannot be performed with the capsule. Consequently, despite the wish of many people, the capsule is not a substitute for endoscopy or colonoscopy. These tests can often help in the diagnosis of ulcerative colitis or Crohn's, provide a decent understanding of where the disease is active, screen for colon cancer and help guide therapy.
Ulcerative colitis only affects the colon (the large intestine or large bowel). The small bowel is not involved in ulcerative colitis. Inflammation in the colon ("—itis" means inflammation) is found only superficially in the lining of the colon, but not through the whole wall, as occurs in Crohn's Disease. The extent of inflammation varies in each individual. In some, it may involve just the rectum (proctitis), the left side (of variable extent) or the entire colon (pan-colitis). While the extent may vary, it initially appears in the rectum and works its way up. The inflammation is always confluent or continuous from the rectum to whatever portion of the colon is inflamed. If left-sided, the inflammation stretches from the rectum throughout the left side of the colon with no normal areas within the inflamed area. Over two-thirds of patients will have inflammation just on the left side at the onset of their ulcerative colitis. However, as often as half of the time, inflammation can progress to involve the entire colon.
The clinical problems caused by ulcerative colitis vary in each patient, but tend to be more similar than in Crohn's. While the symptoms differ to some degree depending on how much of the colon is inflamed, bloody diarrhea tends to be the most consistent problem. Abdominal cramping can be quite common as well, particularly at the time of a bowel movement. While some patients with ulcerative colitis suffer from more persistent pain, generally, that is not the rule. However, pain is often noted with severe flares. Frequent, small stools accompanied by a persistent sense of having to evacuate and a great sense of urgency, is often felt with more significant rectal inflammation. Other symptoms such as fatigue, low energy and feeling rundown are not specific to ulcerative colitis but will often accompany colitis. Fever, (particularly low-grade, below 101) can be caused by ulcerative colitis. If a patient has a temperature greater than 102 degrees, an additional cause such as an infection should be investigated. Ulcerative colitis can also cause symptoms that are outside the bowel (known as systemic or extraintestinal manifestations). Joint pains, particularly in the larger joints (hips, knees) can occur in more than 40 percent of patients, as well as inflammation of the eyes and skin.
Crohn's Disease usually occurs in an area of the lower small intestine called the ileum, where the small intestine ends and connects to the large intestine . Anyone can develop Crohn's disease. It affects men and women almost equally, and children can develop the disease as well. But people with Crohn's disease share a couple of common characteristics:
Unlike ulcerative colitis, Crohn's can develop anywhere in the intestine, from the mouth to the anus. However, it does not jump around. Usually, when it announces itself in one or several locations, it remains there. If surgery is performed, a recurrence is usually at the original site. Most commonly, Crohn's Disease occurs in the last segment of the small bowel (ileum), which is why Crohn's is occasionally referred to as Ileitis. About 70 to 80 percent of the time inflammation can be detected in the last part of the small bowel. The disease in the small bowel may be limited to just a few inches or can be several feet in length. The first half of the small bowel, the duodenum and jejunum, can be involved by as much as 20 percent, the stomach in 5 to 10 percent, and the esophagus 1 to 2 percent. The colon can be the primary site of involvement in about 20 percent of patients with Crohn's disease. Unlike ulcerative colitis, where inflammation is continuous and almost always starts in the rectum, Crohn's more often does not involve the rectum (“rectal sparing”). In addition, Crohn's disease is not always continuous. There can be a diseased segment, followed by a healthy segment, followed by a diseased segment. This type of involvement, typical of Crohn's, is called a “skip lesion.” Crohn's varies a great deal among individuals and is less homogeneous than ulcerative colitis.
Each patient's Crohn's disease manifests itself differently. The symptoms are less similar than with ulcerative colitis. A patient might have a great deal of abdominal pain, but no diarrhea. A child might not have any pain or diarrhea, just fatigue and poor growth. A patient could experience a great amount of diarrhea and nausea. The problems associated depend on:
Most commonly, patients with Crohn's have diarrhea, which can vary from a few loose stools to more than 20 stools per day. However, about 10 percent of patients with Crohn's do not experience any diarrhea. Abdominal pain and tenderness depends on the amount and location of inflammation. As Crohn's most often occurs in the lower-right part of the abdomen, pain will be present usually in that same area as well. Other symptoms can be less specific in terms of location, such as loss of appetite or loss of weight. Weight loss often occurs because patients will not eat normally. They sense it will cause more diarrhea or abdominal pain. Fever (a temperature greater than 100 degrees) can be attributed to intestinal inflammation, but some other problem or complication could be indicated if the temperature is greater than 101.5 or 102 degrees. Fatigue can also be a major problem, as well as an early warning of a problem brewing. Of course, numerous other problems, related or unrelated to Crohn's can cause fatigue. Another major set of problems caused by Crohn's can be fistulas (like a straw or small pipe connecting two areas) or perianal ulcers. Fistulas can cause perianal pain, soreness and drainage of pus or stool.
The first step in managing IBD is to establish a correct diagnosis. Does a patient have ulcerative colitis, Crohn's Disease or is the colitis indeterminate? Once a diagnosis has been made, physicians work with patients to achieve the following goals:
Many medications, but not all, are used to treat both diseases. Crohn's and ulcerative colitis are diseases that have a broad range of severity. Some patients might have minimal disease symptoms every few years; others may have almost nonstop, severe symptoms. The general approach is to start with mild medications to treat mild disease and stronger medications, with their associated risks, reserved for more severe disease. Some use the image or model of a pyramid, starting at the bottom with more widely used therapies that are mild both in risk and benefit, working the way up to medications which are more potent but also have more significant risk of side effects. Five classes of medication are currently available to treat IBD. They include:
Only 20 percent of individuals with ulcerative colitis require surgery. These patients have a colectomy (removal of the entire colon) and either an ileostomy (attaching the end of the small intestine through the abdominal wall to collect stool in a bag) or a colectomy and ileal pouch-anal anastomosis (also called a J-pouch) surgery. In this type of surgery, a new rectum or “pouch” is created out of the last part of the small bowel. The end of the bowel if turned back on itself into a “J” with the bottom of the “J” attached to the anus. A patient undergoing this operation most often has a temporary ileostomy (with an external appliance) until everything is healed, after which the ostomy is closed and the patient then evacuates in a normal way, though with some increased frequency. One function of the colon is to absorb fluid. Without it, more fluid output is generated. Typically, after having this procedure, the individual will have 4-8 pudding-like stools a day. After this surgery, ulcerative colitis is considered cured though occasionally other issues can occur. A colectomy can be performed for patients with ulcerative colitis in a number of instances. For example, when the disease is acutely flaring, not responding to therapy and the individual is very ill. A variety of rare, but acute, life-threatening situations such as a perforation (a hole through the wall of the colon) or a severe bleed where a great deal of blood volume is lost, also requires urgent or immediate intervention by the surgeon. Other candidates for surgery are patients who are unresponsive to therapy, but not necessarily acutely ill. Other patients for whom surgery might be a useful option are those who have become dependent on steroids over an extended period of time despite attempts to wean them. Lastly, if cancer is discovered or other, more subtle “pre-cancer” warnings called dysplasia indicate that cancer is likely to develop , surgery is recommended.
Surgery can be extremely helpful to manage perianal manifestations of Crohn’s disease, abscesses or fistulae. Toxic megacolon, a complication of severe Crohn’s colitis, which occurs in ulcerative colitis as well as Crohn's, usually requires surgery. Another common reason for surgery is to remove a segment of intestine that has been causing persistent symptoms and is not responding to therapy. In Crohn’s, surgery is not a cure, particularly when a section of the small bowel is removed and the intestines are hooked back together (an anastomosis). Recurrence of Crohn’s can be quite high, with symptomatic recurrence of 10 to 15 percent per year. As high as 80 percent of Crohn's patients who have had this surgery will have some recurrence of their disease, even if they are feeling generally well. The J-pouch surgery is also not a procedure usually done for Crohn’s disease, as the recurrence rate is very high and many patients will require having the pouch removed and an ileostomy created instead. However, over 80 percent of patients with Crohn’s who have had an ileostomy have a long-term remission, and many never have recurrence of their disease.
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This site has been underwritten thanks to sponsorship from Abbott Pharmaceuticals, |
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