Many people who have irritable bowel syndrome are concerned that they have been misdiagnosed; they believe that they have inflammatory bowel disease (IBD), not IBS. Perhaps they think they have been misdiagnosed because the names of the two disorders are similar or maybe because IBS is sometimes mistakenly called “colitis.” Many people who have IBS have heard about complications associated with IBD, and they worry that they will need surgery. Other people mistakenly believe that IBS is a precursor to IBD, meaning that if they have IBS, they will eventually develop IBD. A clinical research study designed to measure attitudes and concerns of people who have IBS found that 30 percent of the study population believed that IBS turns into IBD.
Chapters 3 and 5 of this book discuss how IBS can develop for many different reasons, how its symptoms can be bothersome and intrusive, and how the symptoms can be chronic for many people. These chapters also state that IBS never turns into anything dangerous or life threatening, such as IBD or colon cancer. The following case study describes a patient who was concerned that his symptoms were consistent with IBD and not IBS. Later on in this chapter, I’ll summarize information about the two most common inflammatory bowel diseases: Crohn’s disease and ulcerative colitis.
Christopher is a 23-year-old graduate student whose physician sent him for a second opinion in gastroenterology due to concerns that he had IBD. Christopher first noticed symptoms during college. He often had episodes of urgent diarrhea in association with lower abdominal cramps. He reported that sometimes he had the urge to have a bowel movement but only passed mucus. He felt tired and wasn’t sleeping well. He was concerned because his second cousin had similar symptoms and had been diagnosed with Crohn’s disease.
Christopher went to his university’s student health center, where he underwent a careful physical examination that did not show anything abnormal. The physician noted that Christopher’s weight was stable and, focusing on his concerns about possible Crohn’s disease, she did a careful examination of his eyes, mouth, joints, and skin. She did not find any evidence of extra-intestinal Crohn’s disease (see definition later in this chapter). Blood work (CBC and erythrocyte sedimentation rate [ESR]) came back normal, showing no evidence of an infection, inflammation, or anemia. Stool studies from one of Christopher’s episodes of diarrhea all came back normal as well. The student health center physician told Christopher that many of his symptoms were consistent with IBS and that it was possible that stress was precipitating some of his episodes. She suggested some dietary changes and the as-needed use of loperamide.
Christopher took these suggestions to heart but was still concerned that his symptoms represented something other than IBS. The health center physician referred him to a gastroenterologist at the university hospital, who reviewed his medical history, carefully examined his family’s medical history, studied his diet for foods that can prompt symptoms mimicking IBS, and investigated alternative diagnoses such as celiac disease. Christopher’s physical examination was again normal, and the gastroenterologist stated that he did not believe that Christopher had Crohn’s disease or the other common inflammatory bowel disease, ulcerative colitis, but that the only way to be certain was to perform more blood work and a colonoscopy.
Because Christopher had done more Internet research and had learned that Crohn’s disease was most common in young adults and could be hard to diagnose, he decided to undergo further testing. His blood work (a repeat CBC and ESR) and colonoscopy of the entire colon and lower small intestine (terminal ileum), including random biopsies of the lower small intestine and colon, were normal. Although this news seemed to reassure Christopher, during the next two years, he continued to have intermittent symptoms of lower abdominal cramps, spasms, pain, urgency, loose stools, and the passage of mucus. He discussed his symptoms with his parents, who told him that his mother’s aunt had “colitis,” although they weren’t sure of the exact type. This news made Christopher nervous, and he sought out the advice of another gastroenterologist.
Dr. Schneider went over Christopher’s medical history, questioning him about other family members, his stress levels, and his diet. She reviewed his previous diagnostic tests and medical treatments and noted that he had gained weight during the past two years. Dr. Schneider and Christopher discussed how he did not have GI symptoms and felt well when he was on vacation or during long holidays. She acknowledged his concerns about Crohn’s disease and spent time with him reviewing the prevalence rates of Crohn’s disease (uncommon) compared to IBS (common). In addition, she reviewed his test results with him and showed him the data indicating that having very distant relatives with IBD did not increase his risk of having IBD.
When Dr. Schneider asked Christopher about his concerns and fears, he reiterated that he was sure that he had Crohn’s disease and speculated that maybe it had not yet been detected because it was Crohn’s disease of the small intestine. Dr. Schneider acknowledged that approximately one-third of people who have Crohn’s disease have only small bowel disease, and that it could have been missed during Christopher’s colonoscopy (which only examined the colon and the lowermost part of the small intestine, the terminal ileum). The two discussed the risks and benefits of different tests and medications. Christopher stated that he didn’t want to take any more medications (although the loperamide did help his symptoms of diarrhea) but that he did want to be sure of the diagnosis. They agreed to repeat the blood count and to perform another test to look for inflammation in the bloodstream (C-reactive protein) as well as to have Christopher get an x-ray test of his small intestine (upper GI series with small bowel follow-through). All test results were normal.
Christopher now felt more relieved knowing that, over the course of three years, he had not developed any additional symptoms, his blood count had remained normal, and all of his test results were normal (three separate tests to look for inflammation, stool studies, and specialized tests to evaluate the colon and small intestine). He recognized that Crohn’s disease is uncommon compared to IBS, and he learned that having very distant relatives who have IBD probably does not increase his risk of developing IBD (although having a first-degree relative who has IBD does). With this information in mind, Christopher focused on a stress reduction program involving exercise, a more regular schedule, yoga, and visits to a social worker to discuss proactive methods to reduce stress. He followed up with the student health center physician and, several months later, he noted a significant improvement in his symptoms with only the occasional use of loperamide.
In contrast to IBS, inflammatory bowel diseases are not very common. In the United States, approximately 7 out of 100,000 people have Crohn’s disease and 80 out of 100,000 have ulcerative colitis (UC). IBS affects approximately 15,000 out of every 100,000 people.
Crohn’s disease and UC are often characterized as autoimmune disorders, which means that they develop because the body starts to attack itself, causing inflammation in the GI tract. With people who have Crohn’s disease or UC, it is unclear whether their bodies are trying to attack a foreign pathogen or antigen (an appropriate response) or whether their bodies get confused and attack themselves for unknown reasons (an inappropriate response). Regardless of the type of response, this autoimmune process distinguishes Crohn’s disease and UC from IBS, which is not an autoimmune disorder.
Also unlike IBS, Crohn’s disease and UC are characterized by inflammation in the GI tract. People who have Crohn’s disease may have ulcers and inflammation anywhere from the mouth to the anus, whereas inflammation is limited to the colon and anorectal area in people who have UC. In both cases, the inflammation is usually easy to see during a colonoscopy. (Although the colon of a person who has IBS may not function normally, it appears normal when inspected during a colonoscopy.)
A final difference between IBS and IBD is that the majority of patients with Crohn’s disease, and many patients with UC, eventually require surgery. Individuals who have IBS never require surgery specifically for their IBS symptoms. With these key differences in mind, let’s review the two most common forms of IBD: Crohn’s disease and ulcerative colitis.
Crohn’s disease was formally recognized as a disease in 1932, although medical reports from the mid-1700s describe patients with similar symptoms. Crohn’s disease is not common—it affects only 7 to 10 out of every 100,000 people. Although it is most frequently diagnosed in people ages 15 to 30, research studies have shown a small second “peak” in the age of diagnoses, meaning that a substantial number of people are diagnosed with Crohn’s disease for the first time in their seventies. In terms of sex, slightly more women are diagnosed with Crohn’s disease than men.
Unfortunately, similar to the case with IBS, the exact cause of Crohn’s disease is unknown. Clearly, a genetic predisposition exists for the development of Crohn’s disease. If you have a first-degree relative with the disease, your risk of developing it is 14 to 15 times higher than the general population (recognizing, of course, that Crohn’s disease is uncommon, so your risk may increase from 7 to 10 out of 100,000 to 100 to 150 out of 100,000—still fairly low odds). Genetic susceptibility has also been demonstrated in twin studies, in which an identical (monozygotic) twin had Crohn’s disease and her or his twin sibling had nearly a 2 in 3 chance of developing it as well. For reasons not completely known, Ashkenazi Jews are more likely to develop Crohn’s than non-Jews (genetic testing has identified an area on chromosome 16 that may be involved).
Other theories about the cause of Crohn’s disease include previous viral or bacterial infections, stress, and smoking (Crohn’s disease is more prevalent among smokers). However, many experts believe that Crohn’s disease may be triggered by a simple virus or bacterium that combines with a food substance or normal colonic bacteria. This combination is detected by the immune system as “foreign,” initiating an immune response leading to inflammation in the GI tract.
No matter the cause, Crohn’s disease is a persistent immune response in which the body attacks itself and causes inflammation in the GI tract (anywhere from the mouth to the anorectum). Although one of the defining characteristics of Crohn’s disease is a small superficial ulcer (called an apthous ulcer), over time, Crohn’s disease can affect the entire thickness of the intestinal tract, which can lead to significant scarring and the formation of strictures (narrowing of the GI tract). The inflammation can be so severe that it goes through the lining of the GI tract and affects adjacent organs, such as the bladder, uterus, vagina, and even the skin (inflammation that goes from the GI tract to another organ is called a fistula).
Symptoms of Crohn’s disease depend on the section of the GI tract involved and the extent of involvement. Half of all people who have Crohn’s disease have disease of the small intestine and colon. Approximately one-third have Crohn’s disease limited to just the small intestine. A few people have only colonic involvement, and the rare person has Crohn’s disease of the esophagus or stomach. Abdominal pain (often in the area around the umbilicus [belly button], but it can be anywhere in the abdomen) is the most common symptom of Crohn’s disease. Patients may have loose stools and occasional low-grade fevers, and they may lose weight. In addition, many patients have extra-intestinal manifestations of Crohn’s disease, such as inflammation in the eyes (episcleritis and uveitis), arthritis, back pain, ulcers in the mouth, and skin ulcers.
Physicians use a mixture of different tests to diagnose a person with Crohn’s disease. A combination of appropriate symptoms and typical findings (e.g., ulcers in the mouth and on the shin and inflammation in the eyes) on physical examination is the first step to diagnosis. Blood work may show evidence of anemia; unlike with people who have IBS, blood tests that identify inflammation in the body (such as ESR and CRP) are usually elevated in people who have Crohn’s disease. Stool studies may show evidence of blood and inflammatory cells in the stool (these are both absent in stool studies of people who have IBS). Finally, most patients who have suspected Crohn’s disease undergo a colonoscopy and an x-ray study of the small intestine, and these two tests usually show evidence of ulceration and inflammation in the GI tract.
Treatment for Crohn’s disease is complicated and depends on the patient. Unlike treatment for IBS, steroids are frequently used, as are very potent drugs called immunomodulators, which are designed to suppress the immune system and hopefully stop or minimize the autoimmune response. Finally, people who have Crohn’s disease are at an increased risk of developing cancer of the small intestine and colon, and up to 70 percent will eventually require some type of surgery for their disease. Again, this is in stark contrast to the treatment of people who have IBS, who will never require surgery specifically for their IBS symptoms.
Ulcerative colitis, the most common inflammatory bowel disease, was formally recognized as a disease in 1859. Approximately 80 to 120 of every 100,000 people have UC, and it appears to affect men and women equally. Although people of any age group may have ulcerative colitis, it is most common in people between the ages of 20 and 40. Similar to Crohn’s disease, Ashkenazi Jews are more likely to have UC than non-Jews. Genetic predisposition to UC is likely although less common than in people who have Crohn’s disease (approximately 10 percent of people who have UC have a first-degree relative with the disease). Twin studies support a genetic component to UC, although once again, much less so than twin studies of Crohn’s disease. For example, if an identical twin has UC, the other twin has a 30 percent chance of having it (if this was purely a genetic disorder, the identical twin’s risk of UC would be 100 percent).
As with IBS and Crohn’s disease, the cause of UC is unknown. Most experts believe that for a person with a certain genetic background, an infection, an inflammatory process, or an abnormal response to a normal component of the GI tract (such as normal gut microflora) could trigger an autoimmune response and the development of severe inflammation. Strangely enough, smokers seem to be protected from UC (several studies have shown that nonsmokers are more likely to get UC than smokers). Researchers do not know why smoking might be protective for people who have ulcerative colitis but harmful for people who have Crohn’s disease.
Ulcerative colitis generally begins in the rectum and then extends to varying degrees into the colon. Unlike Crohn’s disease, it does not have the potential to affect the mouth, esophagus, stomach, or small intestine. In approximately 50 percent of people who have UC, it is limited to the rectum and sigmoid colon. Thirty percent have inflammation that begins in the rectum and extends past the sigmoid colon but does not reach all the way around the colon to the cecum. Approximately 20 percent of people who have UC have an inflammatory process that affects their entire colon, which is called pancolitis. Ulcerative colitis is different from Crohn’s disease because it only affects the surface of the colon; it does not burrow through the many layers of the bowel wall and thus can’t directly affect other organs.
The main symptoms of UC are diarrhea, bloody stools, abdominal pain, and the passage of mucus. Although these symptoms may appear similar to those of IBS, people who have UC usually notice blood mixed with their stool, or they only evacuate blood clots or bright red blood. Many people who have UC mistakenly think that the bleeding is due to hemorrhoids. No matter what the cause is, the presence of blood in the stool should always prompt a person to seek medical attention. When patients who have UC undergo flexible sigmoidoscopy or colonoscopy, it is clear that the blood loss is due to inflammation of the colon and not hemorrhoids. Similar to the case with Crohn’s disease, people who have UC can have other problems outside of the colon, meaning that they may develop ulcers in their mouth or on their legs and arms, they may have inflammation in their eyes, or they may develop back pain or joint problems.
The diagnosis of UC is made because of a patient’s history, stool samples, blood work, and examination of the colon with either sigmoidoscopy or colonoscopy (see Chapter 8). A history of abdominal pain with diarrhea and evidence of bleeding warrants immediate blood work (CBC), to check for anemia and to rule out an infection, as well as stool studies to rule out an infection of the colon. Many patients who have UC are mildly anemic due to blood loss from the chronically inflamed colon. Stool studies are used to rule out an infection as the cause of the bleeding, because some GI infections (Salmonella, Shigella, Campylobacter, and Yersinia) cause bloody diarrhea. Although stool studies from patients who have UC usually show evidence of inflammation and red blood cells, they do not normally show evidence of an active bacterial or amoebic infection. Endoscopic examination of the colon shows inflammation in a person who has UC (inflammation is not seen in people who have IBS). Endoscopy helps determine if the patient has UC limited to the anorectal area or lower colon or whether it involves the entire colon.
The treatment of UC includes either topical or oral medications that are designed to minimize inflammation and suppress the immune system. The type of medication depends on whether the disease is located only in the lower colon or the entire colon. For patients who have UC located only in the anorectal area and/or sigmoid colon, medicated enemas may be all that is required. For individuals who have inflammation throughout their entire colon, treatment will include oral medications.
Unlike people who have IBS, people who have UC are at higher risk for colon cancer than the general population (the level of risk depends on the number of years with the disease). Some patients who have UC with persistent bleeding or severe inflammation of the colon may require surgery to remove the colon.
• IBS is frequently confused with IBD, even though these two disorders are completely different.
• The two most common types of inflammatory bowel disease (IBD) are Crohn’s disease and ulcerative colitis (UC).
• Both Crohn’s disease and UC involve inflammation in the colon, which can easily be seen by a physician during a colonoscopy. This inflammation is not present in people who have IBS.
• Both Crohn’s disease and UC are treated with medications designed to stop the inflammation that occurs in the GI tract. These medications are quite different from those used to treat IBS.
• Many individuals who have Crohn’s disease and UC eventually require surgery. In contrast, surgery is never needed to treat IBS symptoms.