The practice of medicine is both a science and an art. The science of medicine is built on numbers, which are easily measured and derived from laboratory research, clinical trials, diagnostic tests, and clinical experience. The art of medicine, which has an intuitive aspect, is formed from the practitioner’s myriad emotional, social, educational, and professional experiences. The elements of the art of medicine are much harder to quantify and are obviously more subjective.
To practice the art of medicine, one must have the time to be a careful listener. The astute physician is a good detective, searching out seemingly insignificant details that could later play a major role in the diagnosis and treatment of a patient. To be a good practitioner, one must be able to convey caring and compassion, so that the patient is comfortable communicating honestly. In addition, the provider must be able to provide an opportunity for each patient to tell her or his own story. These things are difficult to accomplish in the current health care climate, in which insurance companies and managed care organizations view the practice of medicine as a business and time spent with patients as something to be strictly rationed.
The field of medicine is also characterized by change, in both its scientific underpinnings and our understanding of people. The evaluation and treatment of people who have irritable bowel syndrome are prime examples of this. During the last two decades, we have witnessed dramatic changes in our approach to conducting research in this area, and we have made great strides in treating this chronic disorder that is frustrating and discouraging for so many people. We now have a better understanding of why IBS develops and how symptoms reflect disordered physiology. We’re more comfortable with the concept of the brain-gut axis and how emotions and moods can influence gut activity. That IBS is commonly associated with other disorders, such as fibromyalgia, migraine headaches, and interstitial cystitis, has come to light in recent years, and our understanding of these relationships has increased our diagnostic capabilities. We are beginning to understand why some people seem to be at a greater risk of developing IBS than other people. And, we are getting better at diagnosing IBS without subjecting patients to unnecessary tests.
All of these changes have improved our ability to treat individuals who have IBS. Meanwhile, changes in the philosophy of medical care have made doctors better at understanding and treating the whole patient, rather than viewing the patient only as a symptom, such as constipation or abdominal pain or bloating. Given these remarkable changes during the last two decades, further advances can be expected in the next decade. I believe that significant progress will be made on multiple fronts in both the basic science and the patient care arenas of IBS. A driving force behind efforts in these directions is the realization by patients and physicians that the current treatments for IBS remain unsatisfactory for many people.
For years, IBS was considered by some patients and physicians to be a catch-all or “wastebasket” diagnosis. Some patients believed that because their doctor could not find a cause, their symptoms were given the label “IBS” for want of a more definitive diagnosis. In addition, because so few treatments were available (“take fiber” and “take more fiber”), there appeared to be little interest in obtaining a better understanding of the disease. “Why bother, since there’s no treatment anyway” was not an uncommon response of physicians and scientists.
The understanding and treatment of IBS have already benefited from one of the greatest advances in the field of medicine in the last two decades, the wider distribution of health care information. Educational efforts have greatly raised the public’s awareness of common medical conditions such as high blood pressure, heart disease, colon cancer, breast cancer, and acid reflux disease. Increasing public awareness of common medical problems has many benefits. It lets patients know that they are not the only ones dealing with this problem. Suffering with symptoms and believing that you are the only one with the condition can be discouraging and frightening. Knowing that your collection of symptoms has a name is empowering, because it enables you to locate vital information that allows you to actively participate in your care.
Increasing public awareness generates interest in research. Unfortunately, funding for scientific research is scarcer than in years past. The amount of funding available for research in a specific area is often based on how common a specific disorder is and how severely the problem affects people’s lives. Demonstrating the high prevalence of IBS, how it affects patients economically, and how it interferes with their daily activities may translate into more funding for research. Also, learning what symptoms are part of which disorder allows people to recognize when their symptoms may be warning signs of serious diseases and increases the likelihood that they will seek medical help earlier than they would have if they had not been properly informed.
All of these points support the broadening of education about IBS. Educational programs are now being conducted by the American College of Gastroenterology and the American Gastroenterological Association (see the Patient Resources section for further details). The International Foundation for Functional Gastrointestinal Disorders (IFFGD), along with other IBS support groups, has also initiated educational programs for the public. Although pharmaceutical companies are often faulted for neglecting some of the health care problems that the United States now faces, many companies provide funding and other resources to educate patients.
Physicians are now considerably more comfortable evaluating and treating people who have IBS than they were 15 years ago. Nearly all doctors were taught years ago that IBS was a diagnosis of exclusion, which meant that all patients who had IBS had to be put through a lengthy battery of tests to exclude all other diseases that could cause the common symptoms of pain, bloating, and either constipation or diarrhea, and only when all other possible causes had been excluded could a patient be diagnosed as having IBS. This inevitably led to a delay in treating patients’ symptoms and was unnecessarily expensive, as many patients underwent tests that were not necessary—and didn’t change either the diagnosis or the treatment. Also, since some diagnostic tests have risks, when people undergo repeated diagnostic procedures, serious side effects can occur.
Over the last several years, increased education about IBS has also been directed at physicians and other health care professionals. Professional education is important, because many health care providers are not as informed as they could be about this disorder. A research study from our laboratory showed that physicians in various specialties differ in their ability to recognize IBS and that they evaluate, test, and treat people who have IBS quite differently. This indicates that physicians have still not achieved consensus on how to safely and effectively diagnose and treat patients who have IBS. Continued educational efforts will improve the ability of all health care providers to diagnose IBS without extensive testing and thus to begin treatment sooner. Education will also improve the quality of treatment received by patients who have IBS, by making health care providers aware of the range of treatments that are available. It will also let them know that this chronic condition can be difficult to treat medically but should never be treated surgically. This last point is important to make, because several studies have demonstrated that people who have IBS are more likely to undergo unnecessary and risky surgery than patients of the same age and sex who do not have IBS.
A great deal of what is known about any medical problem was learned in research labs. Basic science research investigating IBS has been limited, in part because IBS seems not to exist in animals other than humans. However, research studies during the last several years have investigated elements of IBS—the mechanisms of abdominal pain and heightened visceral sensitivity—in both humans and other animals. Ongoing research is examining how the GI tract responds to certain medications, how the brain responds to stimulation within the GI tract, and why people with certain blood types seem to respond better to one type of medication than another. In addition, studies are under way to determine how stress and hormones influence gut function.
With increased public and professional awareness of IBS, clinical research studies will probably also continue to evolve, depending on research funds, of course. A number of key questions remain to be answered: What is the genetic basis for IBS? Is there a genetic explanation for why some people respond to one type of IBS medication while others, with seemingly similar symptoms, do not? Could blood tests be developed to determine whether an individual has the potential to develop IBS? Could a blood test determine whether a person will respond to a type of medication? Could a blood test be developed to detect IBS? This last question is especially important for patients who have abdominal pain and diarrhea, because one of the most important clinical concerns is whether the patient has inflammatory bowel disease rather than IBS. A similar question is whether a stool sample could provide enough information to determine whether somebody has IBS or IBD. Are there ways to prevent IBS from developing after a viral or bacterial gastroenteritis? Can other risk factors be identified and treated, thereby preventing IBS from developing?
In regard to the pathophysiology of IBS, physician-scientists are performing interesting studies to determine how people who have IBS sense pain in their gut and what happens in their brain. Previous studies have shown that the central nervous systems of people who have IBS sense pain differently from those of other people. Continued research in this area is likely to shed more light on the physiology of IBS and eventually lead to better treatments for pain. Several studies are underway looking into why patients who have IBS often have the associated conditions of fibromyalgia, interstitial cystitis, chronic pelvic pain, or migraine headaches. Understanding how these painful conditions are related may help minimize testing, prevent unnecessary surgery, and improve treatment. In addition, clinical research is exploring kinds of treatments that previously were considered alternative—cognitive behavioral therapy, hypnosis, and acupuncture are all areas currently under investigation.
Everyone knows that stress can affect their GI tract. Some people develop abdominal pain during times of stress, others develop diarrhea, and nearly everyone has experienced the sensation of “butterflies” in their stomach when they were excited or anxious. Exactly why this occurs is not known. However, we do know that stress can alter levels of various hormones and neurotransmitters in the body, one of which is corticotropin-releasing factor (CRF, also known as corticotropin-releasing hormone, or CRH). CRF is important to the body’s response to stress and can affect gut motility. Preliminary data from several small research studies have shown that CRF levels in the blood were different in the participants who had IBS than in the healthy volunteers. Theoretically, if CRF levels can be lowered, the probability of diarrhea might be lowered too. Relaxation therapy and stress reduction therapy might prove to be valuable ways to decrease stress, CRF levels, and gut motility.
Looking at cognitive behavioral therapy (CBT), a large multicenter research trial recently found that CBT is effective in treating the chronic abdominal pain that affects people who have IBS. Other studies have shown that CBT can improve other symptoms in patients who have IBS. A large multicenter trial funded by the National Institutes of Health is now under way to evaluate the effectiveness of different types of CBT for people who have IBS. The results of this study may dramatically change physicians’ practices when it comes to recommending CBT and may also change how CBT is performed.
Diet
Once forsaken as a “dead” area of research in IBS, diet is now the focus of several studies. The exciting results obtained from the low-FODMAP diet have stimulated new research efforts into the role of diet in IBS. The close relationship between ingesting food and experiencing symptoms for many people who have IBS raises many questions. Can foods cause IBS? Are some foods more likely to produce symptoms in patients who have IBS than in healthy volunteers? If a specific food is the culprit, could an individual be desensitized to that food? For example, some people who have IBS notice the onset of symptoms or the worsening of symptoms after eating certain foods. Such patients are often referred to an allergist or immunologist to determine whether or not they are truly allergic to these foods. While the diagnostic tests currently available can indicate if someone is allergic to a food, these tests are not capable of determining whether the person has a sensitivity to the food. Thus at present, we can rely only on symptoms to tell us whether a person is sensitive or intolerant to a specific food. Although many scientists and physicians are interested in studying the question of food sensitivity in patients who have IBS, funding for research in this area is severely limited. Future research may promote the development of a blood test that could detect these food sensitivities.
During the development of a new drug, the initial goals are safety and effectiveness. As a drug continues through the various phases of development, additional goals must be met, including that the drug acts as specifically as possible with minimal side effects. The connection between genetic inheritance and IBS is now being explored, and researchers are asking whether a drug could be designed specific to a person’s genetic makeup. This would mean that some people who have IBS and constipation would receive “drug A,” because they have a certain genetic makeup (verified by a blood test), while others who have IBS and constipation would receive “drug B,” because they have a different genetic makeup. The emerging area of science that involves both pharmacology (the study of medications) and genetics is called pharmacogenomics. This field will become significantly more important in the next decade and may yield some discoveries that can be applied to the treatment of IBS.
Below are descriptions of some medications now being studied that may prove helpful in treating IBS.
Medications for constipation. Plecanitide is a new medication that stimulates guanylate cyclase receptors. Preliminary data show that this medication improves symptoms of constipation and abdominal pain. Large multicenter prospective trials need to be conducted to determine whether or not this medication is safe and effective.
Prucalopride is a serotonin agonist (more specifically, a 5-HT4 agonist) that was approved for use in Europe in October 2009 for the treatment of chronic constipation. Three large studies have shown that it is safe and effective in both women and men. It is not yet available in the United States, and studies with patients who have IBS and constipation still need to be performed.
Velusetrag is another serotonin agonist that, in preliminary studies, has been shown to be effective at treating symptoms of constipation. Large prospective studies with patients who have IBS are needed before this medication will become available on the market.
Medications for diarrhea. JNJ-27018966 is a new compound being developed for the treatment of IBS and diarrhea. In preliminary research studies, people who have IBS noted a significant improvement in diarrhea, urgency, and abdominal pain. A large multicenter prospective study is currently under way, and results will probably be available in late 2013.
Dextofisopam is a medication that acts on benzodiazepine receptors in the brain. Results from a study in patients who had IBS and diarrhea or IBS and mixed symptoms were encouraging, because the medication was much better than a placebo at improving symptoms of diarrhea and abdominal pain. Additional study of dextofisopam is needed.
Medications for pain. Abdominal pain is often the most distressing symptom for patients who have IBS. The GI tract is densely populated with opioid (narcotic) receptors, which is one reason narcotics are so effective at treating postoperative pain (such as after an appendectomy or hysterectomy). However, narcotics are quickly addictive, and patients can develop a tolerance for narcotics, requiring ever-higher doses to relieve their pain (see Chapter 18). Researchers are actively investigating other medications that act on these opioid receptors to reduce pain, hoping to find some without the side effects and complications associated with chronic narcotic use.
Alvimopan (a mu-opioid receptor antagonist) is a medication that acts on opioid receptors and, in this case, blocks the mu-receptors. Alvimopan has been shown to ease pain in some patients who have IBS, and in a recent (small) research trial, it also improved symptoms of chronic constipation.
A desire to improve symptoms without the use of oral medications has led patients who have chronic IBS symptoms to search for alternative therapies. Many patients and physicians strongly believe that symptoms of IBS are caused by an overgrowth, or imbalance, of bacteria in the GI tract (see Chapter 11). Several researchers have made very convincing arguments for the role of bacterial overgrowth in the pathogenesis of IBS, although other researchers have not been able to duplicate their study results, and many clinicians remain unconvinced. Antibiotics that act specifically on the gut, with few extra-intestinal side effects, are currently being tested in populations who have IBS. As mentioned above, rifaximin has been shown to improve symptoms of gas, bloating, distention, pain, and diarrhea in many patients who have IBS-D or IBS-M (IBS with mixed symptoms of constipation and diarrhea). A large multicenter trial is currently under way to assess the safety and efficacy of rifaximin for long-term use.
Over one-third of all people in the United States now use some form of alternative medication for their health care needs. Many of these individuals use herbal remedies. The advantages, disadvantages, and dangers of herbal remedies are discussed in Chapter 21. As people who have IBS explore options for treating their symptoms, herbal medications will be used more often. The cautionary note I would make is that these substances should be purchased from a reputable source, and users should research them in authoritative sources before taking them.
Probiotics is the final type of therapy that warrants mention. This is an area in which, I believe, we will witness exceptional growth in the next few years. Although probiotics are commonly used by patients and practitioners, many critical questions need to be answered regarding their role in treating the symptoms of IBS (see Chapter 20). That being said, well-designed studies demonstrating the effectiveness and safety of the probiotic Bifidobacterium infantis are encouraging. Future trials will need to determine which probiotic is best for which patient, in addition to identifying the optimal dose and duration of treatment.
Research into the development and treatment of IBS is active and will probably become even more so over the next decade. New therapies are on the horizon. The fact that pharmaceutical companies are actively looking for new agents to treat symptoms of IBS is encouraging. Patients and practitioners can be optimistic that new treatments will be developed to relieve symptoms and improve quality of life for people who have IBS. We have begun to, and in the future we will be increasingly able to, make sense of IBS.
• Educational efforts and research (both clinical and basic science) have contributed to an increasing public awareness of IBS.
• Treatment for IBS is no longer limited to medications.
• Advances in our understanding of how different foods can influence IBS symptoms now make it possible for many people who have IBS to better control their symptoms on their own.
• Both probiotics and antibiotics can influence the gut microbiota (the bacteria that reside in the large intestine), which in turn can dramatically affect IBS symptoms.
• New medications for the treatment of the different subtypes of IBS will probably be approved in the next five years.