CHAPTER 9
IBS and Other Medical Disorders
Dozens of research studies have shown that people who have irritable bowel syndrome see doctors more frequently than do people who have other chronic medical problems. In fact, a person who has IBS is twice as likely to seek the advice of a doctor than a person who has other chronic medical problems. Given the recurrent symptoms of abdominal pain, bloating, and either constipation or diarrhea that plague people who have IBS, it does not seem unreasonable for people who have IBS to seek the care of a physician more frequently than others do.
However, what seems surprising is that people who have IBS are much more likely to have other medical problems, not related to the gastrointestinal (GI) tract. Both patients and doctors have noticed that many people who have IBS also have a variety of other conditions that do not appear to be related to disturbances in the GI tract. The large number of medical reports and scientific studies that document an increased occurrence of other disorders in patients who have IBS raises the question of whether IBS can affect other parts of the body as well, rather than being limited to the GI tract.
As discussed in Chapter 2, many physicians think that the symptoms of IBS result from visceral hypersensitivity, that the GI tract of people who have IBS is much more sensitive than a healthy person’s GI tract. Stated another way, people who have IBS have a lower threshold for experiencing gastrointestinal pain than do people who do not have IBS. In addition, some people who have IBS experience normal gut sensations and normal gut motility as painful (this subconscious misinterpretation of normal physiology as painful is called allodynia).
The symptoms of the other diseases people who have IBS seem prone to develop include fatigue, headaches, difficulty concentrating, and muscle and joint pain. Pain elsewhere in the body, not affecting the viscera— the hollow organs in the body—is generally referred to as somatic pain. That some people who have IBS have increased somatic pain in addition to the increased visceral pain typical of IBS might support the view that there is a link between IBS and bodily pain in general, a general process producing both heightened visceral pain and heightened somatic pain. Could people who have IBS also have increased sensitivity to pain, or a lower threshold for pain, elsewhere in their body? This question is important to answer because, if true, we would not limit our evaluation and treatment of IBS to just the GI tract but would expand our treatment to the entire body.
The health situation described in the following case story is not unusual among people who have IBS.
Sarah is a 34-year-old woman with a 7-year history of irritable bowel syndrome with constipation. She describes fairly typical symptoms of lower abdominal “cramps and spasms” that occur on a near-daily basis. The abdominal pain or discomfort is always worse just before having a bowel movement. Sarah also has feelings of incomplete evacuation and straining during bowel movements. She frequently feels bloated, and her abdomen is distended. She has struggled with her IBS symptoms and has seen several gastroenterologists. Over the years, all of her test results have been normal (extensive laboratory tests, an abdominal ultrasound, a barium enema, a CT scan of the abdomen and pelvis, and a colonoscopy). She has tried a number of different over-the-counter medications, but they did not improve her symptoms. Until recently, prescription medications hadn’t been much help either, but her current gastroenterologist started her on a low dose of a tricyclic antidepressant for her abdominal pain and polyethylene glycol for her constipation (see Chapters 16 and 18 for a comprehensive discussion on the treatment of constipation symptoms and abdominal pain). Although the results have not been perfect, Sarah’s IBS symptoms have responded very well to these drugs.
Sarah is having an initial visit with a new internist, Dr. Fine, because her health care plan changed and she was forced to find a new primary care provider. In addition to letting this doctor know about the progress in her IBS treatment, Sarah describes a variety of other symptoms she has been experiencing. She has recurrent headaches with flashing lights and develops a “stabbing” sensation behind her right eye. Her teeth and jaws are often painful and she hears a clicking noise when she chews. She always feels tired and can’t seem to get enough rest. Her joints and muscles feel sore and achy, as if she had over-exercised, although she’s been so tired that she hasn’t been able to exercise routinely for months. Because she has a constant urge to urinate but passes only a small amount of urine on each occasion, she is concerned that she might be developing diabetes.
Dr. Fine listens carefully and asks a lot of questions. She is reassured to learn that Sarah has had all of these symptoms for nearly a year and that they are not getting worse. Sarah has not been losing weight and has not been anemic. No one in Sarah’s immediate family has diabetes, celiac disease, inflammatory bowel disease, or any type of cancer. Her previous internist performed extensive blood work just two months ago, all of which produced normal results. She was recently evaluated by a neurologist, who diagnosed her with migraine headaches, which explain the pain and odd sensations in her eyes. Sarah saw her dentist several weeks ago and was told that she has TMJ (temporomandibular joint) syndrome and has been grinding her teeth and clenching her jaw at night. Her dentist recommended the use of a mouth guard at night, to protect her teeth. Sarah asks Dr. Fine if all of these symptoms are connected to her IBS.
Dr. Fine performs a thorough physical examination and finds everything completely normal. She asks Sarah to provide a urine sample to make sure that she does not have a urinary tract infection (she doesn’t) or diabetes (she doesn’t). Dr. Fine tells Sarah that there are some fairly common medical disorders that often go hand in hand with IBS: migraine headaches, TMJ syndrome, fibromyalgia (which causes pain at certain sites), and interstitial cystitis (a bladder condition). Sarah may have all of these conditions. In addition, Dr. Fine says that the excessive fatigue could be consistent with chronic fatigue syndrome, although Sarah hasn’t had the six months of extreme fatigue that would meet the formal definition (discussed below). She questions Sarah more about her sleep and learns that she frequently wakes up and can’t get back to sleep. She reassures Sarah that these symptoms are often associated with IBS and are not caused by a new and more serious disease. Dr. Fine says that sleep disorders are commonly associated with IBS, and disordered sleep can worsen IBS symptoms and also contribute to migraine headaches and feelings of fatigue. Sarah seems relieved to hear this. She and Dr. Fine then work out a treatment strategy to address her multiple symptoms.
Let’s look at each of the conditions that often arise in people who have IBS. They are not always linked with IBS; not everyone who has IBS will develop any of these disorders, and people who have them will not necessarily have IBS as well.
Chronic Fatigue Syndrome
Chronic fatigue syndrome (CFS) affects approximately 1 person out of 250 (0.4 percent of the population). This is far lower than the prevalence of IBS, which affects approximately 1 in 7 adult Americans. Chronic fatigue syndrome is found in all ethnic groups, all age groups (including children), and all socioeconomic groups. It appears to be slightly more common in women than in men, in people with lower incomes, and in those with lower levels of education. Although it can occur at all ages, it is more likely to be diagnosed in people 30 to 50 years old. Why these groups seem to be more likely to have CFS is not known. Although there are many theories, the exact cause of CFS is unknown.
People who have CFS typically complain of severe, debilitating fatigue that doesn’t go away, no matter how much they sleep. This level of fatigue must be present for at least six months and must have had a definite onset (that is, not lifelong) before a diagnosis of CFS can be made. It also must lead to at least a 50 percent reduction in the person’s level of daily activities (social, work, school, personal). Additional symptoms include impaired concentration, difficulty sleeping, recurrent headaches, and a worsening, or relapse, of symptoms after exercise. Some patients have symptoms that mimic a viral infection, such as a sore throat, muscle aches (myalgias), joint aches (arthralgias), and a low-grade fever.
Because of the symptoms that seemed viral, many patients and physicians thought that CFS might be caused by a virus. This hypothesis seemed quite reasonable, and a few scientific studies published many years ago appeared to show that the Epstein-Barr virus (EBV), the virus that causes mononucleosis, was associated with the development of CFS. However, other studies have not been able to reproduce this result, and some have provided evidence that directly contradicts this theory. Because of this evidence, most doctors now do not believe that EBV causes chronic fatigue syndrome.
One current theory about the etiology (causes) of CFS involves chronic activation of the immune system. The immune system is designed to fight infections using specialized cells and chemicals. If the immune system is in “battle” mode all the time, the chronic exposure to these cells and their specialized chemicals could lead to persistent fatigue in some people. Any of the thousands of viruses that can cause an infection in humans could trigger activation of the immune system, which then persists and becomes chronic in nature. Among the viruses considered likely candidates to cause CFS are the varicella zoster virus (the chicken pox virus), cytomegalovirus (CMV), and some of the herpes viruses (such as human herpes virus 6). The low-grade immune response that develops after any of these viral infections may persist for months or even years in some people and may account for the nonspecific symptoms of CFS.
One other factor that could play a role in CFS is stress. It is well known that stress can adversely affect the immune system. One theory is that, for many people, the stress of having to cope with IBS could significantly disrupt the normal function of the immune system, thereby increasing susceptibility to other conditions and worsening a patient’s overall clinical condition.
It is interesting that, as is the case with IBS, the precise etiology of CFS is unknown. Possibly, CFS develops as a result of overlapping causes, which could involve multiple organ systems, including the immune system, the endocrine system (which regulates all kinds of hormones), the musculoskeletal system, and the brain.
As with IBS, the diagnosis of CFS cannot be made if there is an underlying organic problem (for example, an active viral infection, a thyroid disorder, etc.). For that reason, a careful history and physical examination and some laboratory tests must be performed. The physical examination will usually yield normal results, although some people who have CFS have slightly enlarged lymph nodes in their neck, which may indicate a previous viral infection. This finding, however, is nonspecific, meaning that many different factors could lead to mild enlargement of the lymph nodes. Lab tests typically include a complete blood count, a thyroid hormone test, electrolytes, and tests to look at kidney function. Because the fatigue of this condition is persistent and severe, and because of the concern that another disease is being overlooked, doctors and patients often pursue an exhaustive workup in their attempt to uncover the cause of the debilitating fatigue. They want to rule out systemic lupus erythematosus (lupus or SLE for short), scleroderma, Lyme disease, and human immunodeficiency virus (HIV). X-ray studies, including bone x-rays and CT scans, are normally done, and it is not uncommon for patients to be referred to specialists, including rheumatologists, infectious disease specialists, psychiatrists, dieticians, and neurologists. If the cause is chronic fatigue syndrome, none of these consultations will provide another diagnosis that explains the symptoms.
The natural history of CFS is that of a chronic disorder. Some people who have CFS are quite fortunate, in that their symptoms slowly resolve with time and they can return to a normal lifestyle. Others note a gradual, slow improvement but never return to their earlier degree of health. For others, unfortunately, this condition becomes a chronic, disabling disorder. A review of current medical studies estimates that approximately 50 percent of people who develop CFS never fully recover from their symptoms. (The Patient Resources section at the back of this book provides a reference for further information.)
Since there is no known cure for CFS at present, treatment focuses on symptom management. People who have CFS are counseled to obtain adequate rest but to not sleep excessively, because excessive sleep may be harmful in the long run. They should start or continue a graded exercise program to maintain overall fitness and prevent deconditioning (deterioration of their muscles from lack of use). Patients are told to follow a healthy diet and to limit stress in their lives. Medications commonly used to treat CFS include antidepressants; as with IBS, the antidepressants may not address the disease itself but may treat the associated depression or anxiety, sleep disturbance, and the like. These medications may help people to cope with CFS. Low-dose anti-inflammatory agents are often prescribed, along with cognitive behavioral therapy (see Chapter 22). Herbal medications and immunotherapy have been touted as “cures” for CFS, although at present there is no good data to support their use in the general population of people who have CFS.
Fibromyalgia
Fibromyalgia is a condition that affects approximately 2 percent (1 in 50) of adult Americans. It is found in all age groups, races, and socioeconomic classes, but it is more common in women than in men, and the majority of those affected are women between the ages of 30 and 50. In the past, this disorder was called fibromyositis, fibrositis, and myofascial pain syndrome. Although many causes have been proposed, the precise etiology of fibromyalgia is unknown.
Typical symptoms include widespread muscle pain at specific spots called “trigger” or “tender” points, which are tender or painful when pressed (see Figure 9.1). To be formally diagnosed with fibromyalgia, a person must have symptoms of widespread pain for at least 3 months and must have tenderness or pain at 11 out of the 18 trigger points. Pain is generally present on both sides of the body and both above and below the waist. People who have fibromyalgia commonly also have other symptoms, which may include chronic headache, difficulty sleeping, and reduced physical endurance. Several studies have shown that someone who has IBS is much more likely to have fibromyalgia than a person of similar age, gender, and race who does not have IBS. In general, approximately one person out of three who has IBS will also have fibromyalgia.
Physical examination of people who have fibromyalgia reveals no irregularities except for the presence of pain at the trigger (tender) points. Laboratory studies (blood count, thyroid tests, erythrocyte sedimentation rate) are normal in these patients. X-ray studies, CT scans, and MRIs usually do not need to be performed unless the doctor believes that the patient has an inflammatory condition that affects the joints, such as rheumatoid arthritis, or an unusual connective tissue disorder such as lupus (SLE), Sjogren’s syndrome, or polymyalgia rheumatica (PMR).
Figure 9.1. Tender Points (Trigger Points) of Fibromyalgia
People who have IBS often also have fibromyalgia. Fibromyalgia is characterized by a variety of symptoms, including muscle pain and tenderness at specific “trigger” points. There are 18 identified trigger points, which are symmetrically located on the neck, forearms, lower back, upper posterior thighs, and knees. The diagnosis of fibromyalgia is made because of tenderness at these trigger points along with the presence of other typical symptoms.
Treatment of fibromyalgia typically includes rest, heat, an exercise program, the use of anti-inflammatory agents, muscle relaxants, injections of local anesthetics (such as lidocaine) into the trigger point areas, and the use of antidepressants. Pregabalin has been approved by the U.S. Food and Drug Administration for the treatment of fibromyalgia, and many patients find this medication helpful.
Migraine Headaches
Most people have experienced a headache at some point in their life. Headaches are usually a benign but bothersome problem, and they can occur for many reasons. Common causes of headaches include tension (musculoskeletal headaches), eating or drinking icy-cold foods, such as ice cream (these are called ice-pick or ice-cream headaches), and sinus problems.
Migraine headaches differ in distinct ways from most other types of headache. Although symptoms vary dramatically from one person to another, common symptoms include nausea and a stabbing pain behind one eye or on one side of the head. An unusual symptom that may occur is referred to as an aura. An aura usually develops before the pain of the headache begins and may include the sensation of seeing flashing lights or of smelling an unusual smell, like rubber or rotten eggs. On rare occasions, the headache can produce a numbness or tingling in the face that can make people think they are having a stroke or a TIA (transient ischemic attack, also called a ministroke). Most migraine headaches last about 4 to 72 hours, and on average, people who have migraines have one or two episodes per month, although around 10 percent have weekly episodes.
Migraines occur more commonly in people who have IBS than in the general population. In the United States, over 28 million people have migraines. Migraine headaches are three times more likely to occur in women than in men. Most people who have migraines develop them during adolescence. They typically persist throughout adulthood, although many women find relief from their migraine headaches after menopause.
Why migraines occur is not completely understood. Studies of the brain using PET scans (positron emission tomography) to measure brain activity have demonstrated that there is increased activity in the brain stem during migraine headaches. In addition, the blood vessels in the brain may swell and some of the sensory nerves may be activated. Interestingly, as with IBS, serotonin may play a role in the development of migraine headaches.
Triggers that may precipitate a migraine headache include the ingestion of caffeine, alcohol (especially red wine), or food additives, such as MSG (monosodium glutamate); lack of sleep; stress; and exposure to perfumes, soaps, detergents, or deodorants. Diagnostic evaluation typically involves a thorough neurologic exam by the primary health care provider. During this examination, vision is checked, the nerves in the head and neck (cranial nerves) are tested, and muscle strength and reflexes are evaluated. The patient’s risk factors for stroke (diabetes, high blood pressure, elevated cholesterol) are also assessed.
Treatment commonly involves avoiding precipitating factors; using medications for pain such as aspirin, acetaminophen (Tylenol), or anti-inflammatory agents such as ibuprofen; taking medications (such as Imitrex, Zomig, Amerge, Maxalt or midrin) at the start of a migraine; and taking medications regularly to prevent future attacks (beta blockers, calcium channel blockers, tricyclic antidepressants, valproate).
TMJ Syndrome
The temporomandibular joint (TMJ) is the area where the jaw is attached to the skull by the very strong muscles responsible for chewing. Temporomandibular joint syndrome (TMJ syndrome) affects nearly one in five adult Americans, although only a small proportion of them seek treatment from their primary care physician or their dentist. This condition is more common in middle-aged people than in younger adults, and it is more common in women than in men. Typical symptoms include pain and tenderness in the jaw area, in the muscles of the jaw, in the joint itself, and/or under the ears and an inability to fully open the mouth. The person may also experience headaches, neck pain, or a catch or clicking noise in the joint when chewing. Factors that contribute to the development of TMJ include clenching the jaw or grinding the teeth, other dental problems, poor-fitting dentures, and stress. Diagnostic evaluation includes x-rays of the mouth and jaw, looking for displacement of the joint or evidence of injury to the joint. Treatment includes the application of moist heat to the area; temporary restriction to a soft diet so as to rest the muscles and the joint involved in chewing; anti-inflammatory medications like ibuprofen; muscle relaxants; and use of a mouth guard at night to prevent or reduce the impact of teeth grinding and jaw clenching during sleep. Studies have varied in their reporting of the relationship between TMJ syndrome and IBS; overall, TMJ is present in approximately 20 to 60 percent of people who have IBS.
Chronic Pelvic Pain
Many women who have IBS have problems with recurrent pain in the pelvis or pelvic cavity. The pelvic cavity is the area bounded by the hip bones on each side, the pubic bone in front, and the coccyx (tail bone) in back. Within the pelvic cavity lie the bladder, ureters, and parts of the colon and small intestine; in women also the uterus, cervix, and vagina; and in men also the prostate gland. Patients who have chronic pelvic pain are usually first evaluated by their primary care physicians, although if symptoms persist, they may be referred to any of a variety of specialists—gynecologists, obstetricians, urologists, fertility experts, and/or gastroen-terologists. Like IBS, chronic pelvic pain (CPP) is not a narrowly defined disease but a syndrome that can develop for a number of different reasons and involve various organ systems, including the endocrine system (which deals with hormones), the urologic system, the musculoskeletal system, and the reproductive system—hence the variety of specialists to whom one might be referred.
Pelvic pain must be present for at least six months before it is considered chronic in nature. In some patients who have CPP the pain is present on a daily basis, while in others it occurs much less frequently. It may be associated with extremely painful menstrual cycles or painful intercourse (dyspareunia). Sometimes the pain is worse with movement or sitting down. Some of the most common reasons for chronic pelvic pain include endometriosis, “congestion” (swelling) of the veins in the pelvis, scar tissue from previous surgery, bladder problems (such as interstitial cystitis—see below), problems in the muscles that line the pelvic floor, uterine fibroids, a remnant of ovary left despite prior supposed removal of both ovaries, and visceral hypersensitivity. Information gathered from gynecology clinics shows that IBS is frequently also present in women who have painful menstrual cycles, painful intercourse, and CPP.
Treatment of CPP begins with trying to identify the underlying factor that is responsible for the pain. For many patients, this may require a series of visits to different specialists so that specialized testing can be performed. Once the underlying cause is identified, specific treatment can be initiated.
Urinary Problems
Many people who have IBS complain of urinary problems, for instance, increased urinary frequency, increased urination at night, feelings of incomplete urination, spasms or discomfort in the bladder, urinary hesitancy, and inability to completely empty the bladder. Patients who have primary symptoms of urinary urgency and frequency may have an overactive bladder. People who have the symptoms described above who also have pelvic pain and pain partially relieved with urination may have a condition called interstitial cystitis (IC). This is a common condition thought to affect more than 10 million Americans. Typically a chronic condition, it is characterized by symptoms that are very similar to a urinary tract infection (UTI). In fact, many people who have interstitial cystitis have been misdiagnosed as having repeated or recurrent UTIs.
Symptoms of IC include pain or discomfort in the area of the bladder (behind the pubic bone), pain or discomfort with urination, feelings of urinary urgency, and feeling the need to urinate frequently. These symptoms often temporarily improve after urination but then return shortly afterwards. Although less common, some women who have IC complain of bladder pain that awakens them at night or pelvic pain that persists for days after sexual intercourse.
Interstitial cystitis may develop because of inflammation in the bladder wall, recurrent infections in the bladder, or spasms in the bladder wall (which, like the intestinal tract, is made up of smooth muscle). This condition is generally diagnosed with a series of tests, including a urinalysis, urine culture, and tests to measure bladder capacity and bladder emptying ability. Cystoscopy—passing a small lighted instrument into the bladder so that it can be looked at and biopsied if necessary—and distention of the bladder with water (a procedure called hydrodistention) are diagnostic studies commonly used in the evaluation of patients who have symptoms consistent with IC.
Treatment of IC is effective in many patients. As with IBS, effective treatment begins with educating the patient about the condition. Treatment also typically involves changes in diet (avoiding acidic foods, carbonated beverages, alcohol, caffeine), the use of medications to help relax the bladder, anti-inflammatory agents like ibuprofen, tricyclic antidepressants (TCAs), biofeedback, physical therapy, acupuncture, or the use of medications directly instilled into the bladder (such as DMSO, lido-caine, pentosan polysulfate, or heparin). Pentosan polysulfate (Elmiron), a polysaccharide molecule (a long sugar molecule) is the only drug currently approved by the Food and Drug Administration to treat interstitial cystitis. It is thought to improve symptoms by improving healing in the bladder wall, although it may take three to four months before any sustained benefits are noted while on this medication. Some people note a small amount of hair loss while taking pentosan polysulfate; its safety in pregnancy is unknown. In the rare patient who has persistent symptoms, surgery may provide some benefit, and there are preliminary data showing that electrical stimulation of the bladder may help some people who have IC.
Links with IBS?
Pain is a defining symptom of IBS and is the number one reason people who have IBS seek the care of a physician. For many people who have IBS, this pain is limited to the abdomen and pelvis. However, many patients also have somatic pain—pain that involves their bone, muscle, joints, or skin. It is tempting to try to link the pain in the GI tract with the pain elsewhere in the body, especially since so many patients who have IBS experience both. The connection between somatic pain and visceral pain in people who have IBS is not clear-cut, though, for a number of reasons. For example, most patients who have IBS and visceral pain do not also have associated somatic pain, so patients who have IBS and both visceral and somatic pain represent a minority of people who have IBS. Also, some who have an overlap of these two pain syndromes experience relief of one type of pain with treatment but no relief of the other type of pain. We would expect that if the pains came from a single underlying problem or precipitating event, then when the pain of one syndrome responded to a particular medication, so would the other. Finally, if two problems were intimately connected, then their natural histories would be similar. In fact, however, it is quite common for somatic pain syndromes to improve while the visceral pain lingers on.
Scientists have proposed several theories in an attempt to link increased visceral pain with increased somatic pain in patients who have IBS. For example, hyperreactive smooth muscle, autonomic nervous system dysfunction, and altered neuroendocrine function are all possible causative factors for both types of pain. At present, however, there is no good scientific data to support any of these theories. Thus, somatic pain and visceral pain, although found together in a subgroup of patients who have IBS, must at this point be considered two separate physiological processes.
One interesting way to connect these two processes would be to look for similarities in how patients react to both kinds of pain. It is well known that people who have IBS are more sensitive to pain in their GI tract. Perhaps people who have TMJ syndrome, migraine headaches, and fibromyalgia are also hypersensitive to pain. This would mean that someone who has both IBS and fibromyalgia would be more sensitive to pain in both the GI tract and in the musculoskeletal system, compared to healthy people. In addition, it is possible that significant stress, anxiety, or depression causes both of these kinds of problems to flare up. Clearly, further research is needed into these questions.
Summary
• Many patients who have IBS also have other types of pain syndromes.
• Some of the most common disorders associated with IBS include chronic fatigue syndrome, fibromyalgia, migraine headaches, TMJ syndrome, and interstitial cystitis.
• It is tempting to try to link these problems with IBS, looking for similar causes (for example, a viral infection), but there are as yet no good scientific data to support such a connection.
• It is possible that these diverse pain syndromes, which can affect many areas of the body, may all be related by an increased sensitivity to pain.