- Indigestion definition (dyspepsia) and facts
- What is indigestion (dyspepsia, upset stomach)? Is it common?
- What are the signs and symptoms of indigestion or upset stomach?
- Abdominal discomfort and excessive air in the stomach
- Is burping (belching) a symptom of indigestion?
- How long does indigestion (dyspepsia) last?
- What causes indigestion (dyspepsia)?
- How is indigestion (dyspepsia) diagnosed?
- What natural or home remedies are used to treat dyspepsia (indigestion)?
- What treatments relieve and cure indigestion (dyspepsia)?
- Pro-motility medication for indigestion
- Diet and indigestion
- Antidepressants for indigestion
- Psychological treatments for indigestion
- Smooth muscle relaxants for indigestion
- Which specialties of doctors treat indigestion (dyspepsia)?
- What are the complications of indigestion (dyspepsia)?
- What can a person expect during the diagnosis and treatment of indigestion (prognosis)?
- What other diseases or conditions mimic indigestion (dyspepsia)?
- What research is ongoing for treatments to cure indigestion (dyspepsia)?
Indigestion definition (dyspepsia) and facts
- Indigestion (dyspepsia) is a functional disease in which the gastrointestinal (GI) organs, primarily the stomach and first part of the small intestine (and occasionally the esophagus), function abnormally. It is a chronic disease in which the symptoms fluctuate in frequency and intensity usually over many months or years. It may occur every day or intermittently for days or weeks at a time followed by days or weeks of relief (a pattern referred to as periodicity).
- Theories of the cause of indigestion include abnormal input from intestinal sensory nerves, abnormal processing of input from the sensory nerves, and abnormal stimulation of the intestines by motor nerves.
- The primary symptoms of indigestion are
- The symptoms most often are provoked by eating.
- Indigestion frequently occurs during pregnancy, though the majority of the time it is actually caused by acid reflux.
- Indigestion is diagnosed on the basis of typical symptoms and the absence of other GI diseases, particularly acid-related diseases (acid indigestion, esophagitis, gastritis, and ulcers), and non-gastrointestinal diseases that might give rise to the symptoms.
- Since the heart sits near the stomach, there often is confusion about what is causing lower chest or upper abdominal pain. Therefore, indigestion should be considered in anyone with lower chest pain, and heart attack should be considered in anyone with upper abdominal pain. Occasionally, the discomfort of indigestion can be felt in the back.
- Testing in indigestion is directed primarily at excluding the presence of other GI diseases and non-GI diseases. Some patients may require specific testing of certain GI functions. It is important to exclude other causes for the indigestion since their treatment will be different than that for indigestion without a clear cause.
- Treatment in indigestion for which there is no other cause found, is primarily with education as well as smooth muscle relaxant and promotility drugs. There also may be a role for anti-depressant drugs and dietary changes. Because acid reflux is so common, a trial of potent stomach acid suppression often is used as the initial treatment.
- Many people are able to identify specific foods that provoke their indigestion. Despite this fact, there are few foods whose avoidance can be universally recommended since not all people with indigestion have trouble with the same foods. There also are no foods or diets that can be recommended for preventing indigestion other than those that eliminated foods that provoke symptoms.
- There is no evidence that home remedies or natural remedies prevent indigestion.
- Future advances in the treatment of indigestion depend on a clearer understanding of its many cause(s).
What is indigestion (dyspepsia, upset stomach)? Is it common?
Indigestion is one of the most common ailments of the bowel (intestines), affecting an estimated 20% of persons in the United States. Perhaps only 10% of those affected actually seek medical attention for their indigestion. Indigestion is not a particularly good term for the ailment since it implies that there is "dyspepsia" or abnormal digestion of food, and this most probably is not the case. In fact, another common name for dyspepsia is indigestion, which, for the same reason, is no better than the term dyspepsia! Doctors frequently refer to the condition as non-ulcer dyspepsia to distinguish it from the more common acid or ulcer-related symptoms.
Dyspepsia (indigestion) is best described as a functional disease. (Sometimes, it is called functional dyspepsia.) The concept of functional disease is particularly useful when discussing diseases of the gastrointestinal tract. The concept applies to the muscular organs of the gastrointestinal tract, the esophagus, stomach, small intestine, gallbladder, and colon that are controlled y nerves. What is meant by the term, functional, is that either the muscles of the organs or the nerves that control the organs are not working normally, and, as a result, the organs do not function normally, and the dysfunction causes the symptoms. The nerves that control the organs include not only the nerves that lie within the muscles of the organs but also the nerves of the spinal cord and brain.
Some gastrointestinal diseases can be seen and diagnosed with the naked eye, such as ulcers of the stomach and can be seen at surgery, on X-rays, and by endoscopy. Other diseases cannot be seen with the naked eye but can be seen and diagnosed under the microscope. For example, gastritis (inflammation of the stomach) can be diagnosed by microscopic examination of biopsies of the stomach. In contrast, gastrointestinal functional diseases cannot be seen with the naked eye or the microscope. Accordingly, and by default, functional gastrointestinal diseases are those that involve abnormal function of gastrointestinal organs in which the abnormalities cannot be seen in the organs with either the naked eye or the microscope.
In some instances, the abnormal function can be demonstrated by tests (for example, gastric emptying studies or antro-duodenal motility studies). However, the tests often are complex, are not widely available, and do not reliably detect the functional abnormalities.
Occasionally, diseases that are thought to be functional are ultimately found to be associated with abnormalities that can be seen by the naked eye or under the microscope. Then, the disease moves out of the functional category. An example of this would be Helicobacter pylori (H. pylori) infection of the stomach. Some patients with mild upper gastrointestinal symptoms who were thought to have abnormal function of the stomach or intestines have been found to have stomachs infected with H. pylori. This infection can be diagnosed under the microscope by identifying the bacterium in biopsies from the stomach. When patients are treated with antibiotics, the H. pylori and symptoms disappear. Thus, recognition of infections with Helicobacter pylori has removed some patients' symptoms from the functional disease category.
The distinction between functional disease and non-functional disease may, in fact, be blurry. Thus, even functional diseases probably have associated biochemical or molecular abnormalities that ultimately will be able to be measured. For example, functional diseases of the stomach and intestines may be shown ultimately to be associated with reduced or increased levels of normal chemicals within the gastrointestinal organs, the spinal cord, or the brain. Should a disease that is demonstrated to be due to a reduced or increased chemical still be considered a functional disease? In this theoretical situation, we can't see the abnormality with the naked eye or the microscope, but we can measure it. If we can measure an associated or causative abnormality, should the disease no longer be considered functional, even though the disease (symptoms) are being caused by abnormal function? The answer is unclear.
Despite the shortcomings of the term, functional, the concept of a functional abnormality is useful for approaching many of the symptoms originating from the muscular organs of the gastrointestinal tract. To repeat, this concept applies to those symptoms for which there are no associated abnormalities that can be seen with the naked eye or the microscope.
While dyspepsia is a major functional disease(s), it is important to mention several other functional diseases. A second major functional disease is the irritable bowel syndrome, or IBS. The symptoms of IBS are thought to originate primarily from the small intestine and/or colon. The symptoms of IBS include abdominal pain that is accompanied by alterations in bowel movements (defecation), primarily constipation or diarrhea. In fact, indigestion and IBS may be overlapping diseases since up to half of patients with IBS also have symptoms of indigestion. A third distinct functional disorder is non-cardiac chest pain. This pain may mimic heart pain (angina), but it is unassociated with heart disease. In fact, non-cardiac chest pain is thought to often result from a functional abnormality of the esophagus.
Functional disorders of the gastrointestinal tract often are categorized by the organ of involvement. Thus, there are functional disorders of the esophagus, stomach, small intestine, colon, and gallbladder. The amount of research that has been done with functional disorders is greatest in the esophagus and stomach (for example, non-cardiac chest pain, indigestion), perhaps because these organs are easiest to reach and study. Research into functional disorders affecting the small intestine and colon (IBS) is more difficult to conduct, and there is less agreement among the research studies. This probably is a reflection of the complexity of the activities of the small intestine and colon and the difficulty in studying these activities. Functional diseases of the gallbladder (referred to as biliary dyskinesia), like those of the small intestine and colon, also are more difficult to study, and at present they are less well-defined. Each of the functional diseases is associated with its own set of characteristic symptoms.
What are the signs and symptoms of indigestion or upset stomach?
We usually think of symptoms of indigestion as originating from the upper gastrointestinal tract, primarily the stomach and first part of the small intestine. These symptoms include:
- upper abdominal pain or discomfort (above or around the navel),
- nausea (with or without vomiting),
- abdominal bloating (the sensation of abdominal fullness without visible distention),
- early satiety (the sensation of fullness after a very small amount of food),
- abdominal distention (visible swelling as opposed to bloating), and
- lower chest pain.
The symptoms most often are provoked by eating, which is a time when many different gastrointestinal functions are called upon to work in concert. This tendency to occur after meals is what gave rise to the erroneous notion that indigestion might be caused by an abnormality in the digestion of food.
Abdominal discomfort and excessive air in the stomach
Everyone knows that when they have mild abdominal discomfort, belching often relieves the problem. This is because excessive air in the stomach often is the cause of mild abdominal discomfort; as a result, people force belches whenever mild abdominal discomfort is felt, whatever the cause. Unfortunately, if there is no excessive gas to be expelled, forced belches do nothing more than draw air into the esophagus. Usually this air is expelled during the same belch (referred to as a supradiaphragmatic belch), but the air also may enter the stomach, and itself result in excess gas that must be expelled with additional belching.
If the problem causing the discomfort is not excessive air in the stomach, then belching does not provide relief. As mentioned previously, it even may make the situation worse by increasing air in the stomach. When belching does not ease the discomfort, the belching should be taken as a sign that something may be wrong within the abdomen, and the cause of the discomfort should be sought. Belching by itself, however, does not help the physician determine what may be wrong because belching can occur in virtually any abdominal disease or condition that causes discomfort.
Is burping (belching) a symptom of indigestion?
It is appropriate to discuss belching in detail since it is a commonly misunderstood symptom associated with indigestion.
- The ability to belch is almost universal.
- Belching, also known as burping or eructating, is the act of expelling gas from the stomach out through the mouth.
- The usual cause of belching is a distended (inflated) stomach that is caused by swallowed air or gas.
- The distention of the stomach causes abdominal discomfort, and the belching expels the air and relieves the discomfort.
- The common reasons for swallowing large amounts of air (aerophagia) or gas are
- People often are unaware that they are swallowing air.
- "Burping" infants during bottle or breastfeeding is important in order to expel air in the stomach that has been swallowed with the formula or milk.
Excessive air in the stomach is not the only cause of belching.
- For some people, belching becomes a habit and does not reflect the amount of air in their stomachs.
- For others, belching is a response to any type of abdominal discomfort and not just to discomfort due to increased gas.
How long does indigestion (dyspepsia) last?
Indigestion is a chronic disease that usually lasts years, if not a lifetime. It does, however, display periodicity, which means that the symptoms may be more frequent or severe for days, weeks, or months and then less frequent or severe for days, weeks, or months. The reasons for these fluctuations are unknown. Because of the fluctuations, it is important to judge the effects of treatment over many weeks or months to be certain that any improvement is due to treatment and not simply to a natural fluctuation in the frequency or severity of the disease.
What causes indigestion (dyspepsia)?
Non-gastrointestinal causes of indigestion
It's not surprising that many gastrointestinal (GI) diseases have been associated with indigestion. However, many non-GI diseases also have been associated with indigestion. Examples of non-GI causes of indigestion include
- thyroid disease,
- hyperparathyroidism (overactive parathyroid glands), and
- severe kidney disease.
It is not clear, however, how these non-GI diseases might cause indigestion.
Another important cause of indigestion is drugs. Many drugs are frequently associated with indigestion, for example, nonsteroidal anti-inflammatory drugs (NSAIDs such as ibuprofen), antibiotics, and estrogens). In fact, most drugs are reported to cause indigestion in at least some people.
Gastrointestinal causes of indigestion
As discussed previously, most indigestion (not due to non-GI diseases or drugs) is believed to be due to abnormal function of the muscles of the organs of the gastrointestinal tract or the nerves controlling the organs. The nervous control of the GI tract, however, is complex. A system of nerves runs the entire length of the gastrointestinal tract from the esophagus to the anus in the muscular walls of the organs. These nerves communicate with other nerves that travel to and from the spinal cord. Nerves within the spinal cord, in turn, travel to and from the brain. (The GI tract is exceeded in the numbers of nerves it contains only by the spinal cord and brain.) Thus, abnormal function of the nervous system in indigestion might occur in a gastrointestinal muscular organ, the spinal cord, or the brain.
The nervous system controlling the gastrointestinal organs, as with most other organs, contains both sensory and motor nerves. The sensory nerves continuously sense what is happening (activity) within the organ and relay this information to nerves in the organ's wall. From there, information can be relayed to the spinal cord and brain. The information is received and processed in the organ's wall, the spinal cord, or the brain. Then, based on this sensory input and the way the input is processed, commands (responses) are sent to the organ over the motor nerves. Two of the most common motor responses in the intestine are contraction or relaxation of the muscle of the organ and secretion of fluid and/or mucus into the organ.
As already mentioned, abnormal function of the nerves of the gastrointestinal organs, at least theoretically, might occur in the organ, spinal cord, or brain. Moreover, the abnormalities might occur in the sensory nerves, the motor nerves, or at processing centers in the intestine, spinal cord, or brain.
Some researchers argue that the cause of functional diseases is abnormalities in the function of sensory nerves. For example, normal activities, such as stretching of the small intestine by food, may give rise to sensory signals that are sent to the spinal cord and brain, where they are perceived as painful. Other researchers argue that the cause of functional diseases is abnormalities in the function of motor nerves. For example, abnormal commands through the motor nerves might produce painful spasm (contraction) of the muscles. Still others argue that abnormally functioning processing centers are responsible for functional diseases because they misinterpret normal sensations or send abnormal commands to the organ. In fact, some functional diseases may be due to sensory dysfunction, motor dysfunction, or both sensory and motor dysfunction. Others may be due to abnormalities within the processing centers.
An important concept that is relevant to these several potential mechanisms (causes) of functional diseases is the concept of "visceral hypersensitivity". This concept states that diseases affecting the gastrointestinal organs (viscera) "sensitize" (alter the responsiveness of) the sensory nerves or the processing centers to sensations coming from the organ. According to this theory, a disease such as colitis (inflammation of the colon) can cause permanent changes in the sensitivity of the nerves or processing centers of the colon. As a result of this prior inflammation, normal stimuli are perceived (felt) as abnormal (for example, as being painful). Thus, a normal colonic contraction may be painful. It is not clear what prior diseases might lead to hypersensitivity in people, although infectious diseases (bacterial or viral) of the gastrointestinal tract are mentioned most often. Visceral hypersensitivity has been demonstrated clearly in animals and people. Its role in the common functional diseases, however, is unclear.
Another potential cause of indigestion is bacterial overgrowth of the small intestine (small intestinal bacterial overgrowth or SIBO), although the frequency with which this condition causes indigestion has not been determined, and there is little research in the area. The relationship between overgrowth and indigestion needs to be pursued, however, since many of the symptoms of indigestion are also symptoms of bacterial overgrowth. Overgrowth can be diagnosed by hydrogen breath testing and is treated primarily with antibiotics.
Other diseases and conditions can aggravate functional diseases, including indigestion. Anxiety and/or depression are probably the most commonly-recognized exacerbating factors for patients with functional diseases. Another aggravating factor is the menstrual cycle. During their periods, women often note that their functional symptoms are worse. This corresponds to the time during which the female hormones, estrogen and progesterone, are at their highest levels. Furthermore, it has been observed that treating women who have indigestion with leuprolide (Lupron), an injectable drug that shuts off the body's production of estrogen and progesterone, is effective at reducing symptoms of indigestion in premenopausal women. These observations support a role for hormones in the intensification of functional symptoms.
How is indigestion (dyspepsia) diagnosed?
Indigestion is diagnosed primarily on the basis of typical symptoms and the exclusion of non-functional gastrointestinal diseases (including acid-related diseases), non-gastrointestinal diseases, and psychiatric illness. There are tests for identifying abnormal gastrointestinal function directly, but they are limited in their ability to do so.
What natural or home remedies are used to treat dyspepsia (indigestion)?
Studies of natural and home remedies for indigestion are few. Most recommendations for natural and home remedies have little evidence to support their use. Several potential remedies, however, deserve mention including:
- Acid-suppressing remedies: The most common cause of dyspepsia is probably gastrointestinal reflux disease (acid reflux or GERD). That may be why remedies such as baking soda, which neutralizes stomach acid, have been recommended. Even if baking soda works, it is more effective (and probably safer) to use antacids in liquid or pill form for this purpose.
- Ginger: Ginger has been demonstrated to relieve nausea. One small study showed it to be ineffective in relieving dyspepsia, but ginger is harmless and worth a try if nausea is a component of the dyspepsia.
- Peppermint: Peppermint has been demonstrated to have effects on the function of the gastrointestinal tract; it is among the most potent inhibitors of intestinal muscles. It is effective in another functional disease, irritable bowel syndrome, but there is minimal evidence that it is effective in dyspepsia. Nevertheless, like ginger, it is harmless and worth a try.
- Meals: Eating smaller, more frequent meals.
- Lifestyle changes: Stay away from specific foods and drinks, smoking, and alcohol if they provoke symptoms.
What treatments relieve and cure indigestion (dyspepsia)?
The treatment of indigestion is a difficult and unsatisfying topic because so few drugs have been studied and have been shown to be effective. Moreover, the drugs that have been shown to be effective have not been shown to be very effective. This difficult situation exists for many reasons including:
- Life-threatening illnesses (for example, cancer, heart disease, and high blood pressure) are the illnesses that capture the public's interest and, more importantly, research funding. Indigestion is not a life-threatening illness and has received little research funding. Because of the lack of research, an understanding of the physiologic processes (mechanisms) that are responsible for indigestion has been slow to develop. Effective drugs cannot be developed until there is an understanding of these mechanisms.
- Research in indigestion is difficult. Indigestion is defined by subjective symptoms (such as pain) rather than objective signs (for example, the presence of an ulcer). Subjective symptoms are more unreliable than objective signs in identifying homogenous groups of patients. As a result, groups of patients with indigestion who are undergoing treatment are likely to contain some patients who do not have indigestion, which may dilute (negatively affect) the results of the treatment. Moreover, the results of treatment must be evaluated on the basis of subjective responses (such as improvement of pain). In addition to being more unreliable, subjective responses are more difficult to measure than objective responses (for example, healing of an ulcer).
- Different subtypes of indigestion (for example, abdominal pain and abdominal bloating) are likely to be caused by different physiologic processes (mechanisms). It also is possible, however, that the same subtype of indigestion may be caused by different mechanisms in different people. What's more, any drug is likely to affect only one mechanism. Therefore, it is unlikely that any one medication can be effective in all-even most-patients with indigestion, even patients with similar symptoms. This inconsistent effectiveness makes the testing of drugs particularly difficult. Indeed, it can easily result in drug trials that demonstrate no efficacy (usefulness) when, in fact, the drug is helping a subgroup of patients.
- Subjective symptoms are particularly prone to responding to placebos (inactive drugs). In fact, in most studies, 20% to 40% of patients with indigestion will improve if they receive placebo drugs. Now, all clinical trials of drugs for indigestion require a placebo-treated group for comparison with the drug-treated group. The large placebo response means that these clinical trials must utilize large numbers of patients to detect meaningful (significant) differences in improvement between the placebo and drug groups. Therefore, these trials are expensive to conduct.
The lack of understanding of the physiologic processes (mechanisms) that cause indigestion has meant that treatment usually cannot be directed at the mechanisms. Instead, treatment usually is directed at the symptoms. For example, nausea is treated with medications that suppress nausea but do not affect the cause of the nausea. On the other hand, the psychotropic drugs (antidepressants) and psychological treatments (such as cognitive behavioral therapy) treat hypothetical causes of indigestion (for example, abnormal function of sensory nerves and the psyche) rather than causes or even the symptoms. Treatment for indigestion often is similar to that for irritable bowel syndrome (IBS) even though the causes of IBS and indigestion are likely to be different.
It is important to educate patients with indigestion about their illness, particularly by reassuring them that the illness is not a serious threat to their physical health (though it may be to their emotional health). Patients need to understand the potential causes for the symptoms. Most importantly, they need to understand the medical approach to the problem and the reasons for each test or treatment. Education prepares patients for a potentially prolonged course of diagnosis and trials of treatment. Education also may prevent patients from falling prey to the charlatans who offer unproven and possibly dangerous treatments for indigestion. Many symptoms are tolerable if patients' anxieties about the seriousness of their symptoms can be relieved. It also helps patients deal with symptoms when they feel that everything that should be done to diagnose and treat, in fact, is being done. The truth is that psychologically healthy people can tolerate a good deal of discomfort and continue to lead happy and productive lives.
Pro-motility medication for indigestion
One of the leading theories for the cause of indigestion is abnormalities in the way gastrointestinal muscles function. The function of muscles may be abnormally increased, abnormally decreased, or it may by uncoordinated. There are medications, called smooth muscle relaxants that can reduce the activity of the muscles and other drugs that can increase the activity of the muscles, called promotility drugs.
Many of the symptoms of indigestion can be explained on the basis of reduced activity of the gastrointestinal muscles that results in slowed transport (transit) of food through the stomach and intestine. (It is clear, as discussed previously, that there are other causes of these symptoms in addition to slowed transit.) Such symptoms include nausea, vomiting, and abdominal bloating. When transit is severely affected, abdominal distention (swelling) also may occur and can result in abdominal pain. (Early satiety is unlikely to be a function of slowed transit because it occurs too early for slowed transit to have consequences.) Theoretically, drugs that speed up the transit of food should, in at least some patients, relieve symptoms of indigestion that are due to slow transit.
The number of promotility drugs that are available for use clinically is limited. Studies of their effectiveness in indigestion are even more limited. The most studied drug is cisapride (Propulsid), a promotility drug that was withdrawn from the market because of serious cardiac side effects. (Newer drugs that have similar effects but lack the toxicity are being developed.) The few studies with cisapride for indigestion were inconsistent in their results. Some studies demonstrated benefits whereas others showed no benefit. Cisapride was effective in patients with severe emptying problems of the stomach (gastroparesis) or severely slowed transit of food through the small intestine (chronic intestinal pseudo-obstruction). These two diseases may or may not be related to indigestion.
Another promotility drug that is available is erythromycin, an antibiotic that stimulates gastrointestinal smooth muscle as one of its side effects. Erythromycin is used to stimulate smooth muscles of the gastrointestinal tract at doses that are lower than those used for treating infections. There are no studies of erythromycin in indigestion, but erythromycin is effective in gastroparesis and probably also in chronic intestinal pseudo-obstruction.
Metoclopramide (Reglan) is another promotility drug that is available. It has not been studied, however, in indigestion. Moreover, it is associated with some troubling side effects. Therefore, it may not be a good drug to undergo further testing in indigestion.
Domperidone (Motilium) is a promotility drug that is available in the U.S., but requires a special permit from the US Food and Drug administration. As a result, it is not very commonly prescribed. It is an effective drug with minimal side effects.
Diet and indigestion
Dietary factors have not been well-studied in the treatment of indigestion. Nevertheless, people often associate their symptoms with specific foods (such as salads and fats). Although specific foods might worsen the symptoms of indigestion, they usually are not the cause of indigestion. (Intolerance to specific foods, for example, lactose intolerance [milk] and allergies to wheat, eggs, soy, and milk protein are not considered functional diseases like indigestion). The common placebo response in functional disorders such as indigestion also may explain the improvement of symptoms in some people with the elimination of specific foods.
Dietary fiber often is recommended for patients with IBS, but fiber has not been studied in the treatment of indigestion. Nevertheless, it probably is reasonable to treat patients with indigestion with fiber if they also have constipation.
Intolerance to lactose (the sugar in milk) often is blamed for indigestion. Since indigestion and lactose intolerance both are common, the two conditions may coexist. In this situation, restricting lactose will improve the symptoms of lactose intolerance, but will not affect the symptoms of indigestion. Lactose intolerance is easily determined by a milk challenge testing the effects of lactose (hydrogen breath testing) or trying a strict lactose elimination diet. If lactose is determined to be responsible for some or all of the symptoms, elimination of lactose-containing foods is appropriate. Unfortunately, many patients stop drinking milk or eating milk-containing foods without good evidence that it improves their symptoms. This often is detrimental to their intake of calcium which may contribute to osteoporosis.
One of the food substances most commonly associated with the symptoms of indigestion is fat. The scientific evidence that fat causes indigestion is weak. Most of the support is anecdotal (not based on carefully done, scientific studies). Nevertheless, fat is one of the most potent influences on gastrointestinal function. (It tends to slow down the gastrointestinal muscles while it causes the muscles of the gallbladder to contract.) Therefore, it is possible that fat may worsen indigestion even though it doesn't cause it. Moreover, reducing the ingestion of fat might relieve symptoms. A strict low fat diet can be accomplished fairly easily and is worth trying. Additionally, there are other health-related reasons for reducing dietary fat.
Other dietary factors, fructose, and other sugar-related foods (fermentable, oligo- di- and mono-saccharides and polyols or FODMAPs), have been suggested as a cause of indigestion since many people do not fully digest and absorb them before they reach the distal intestine. Fructose intolerance and perhaps also FODMAP intolerance can be diagnosed with a hydrogen breath test using fructose and treated by elimination of fructose and/or FODMAP containing foods from the diet. Unfortunately, fructose and FODMAPs are widespread among fruits and vegetables, and fructose is found in high concentrations in many food products sweetened with corn syrup. Thus, an elimination diet can be difficult to maintain.
Antidepressants for indigestion
Patients with functional disorders, including indigestion, are frequently found to be suffering from depression and/or anxiety. It is unclear, however, if the depression and anxiety are the cause or the result of the functional disorders or are unrelated to these disorders. (Depression and anxiety are common and, therefore, their occurrence together with functional disorders may be coincidental.) Several clinical trials have shown that antidepressants are effective in IBS in relieving abdominal pain. Antidepressants also have been shown to be effective in unexplained (non-cardiac) chest pain, a condition thought to represent a dysfunction of the esophagus. Antidepressants have not been studied adequately in other types of functional disorders, including indigestion. It probably is reasonable to treat patients with indigestion with psychotropic drugs if they have moderate or severe depression or anxiety.
The antidepressants work in functional disorders at relatively low doses that have little or no effect on depression. It is believed, therefore, that these drugs work not by combating depression, but in different ways (through different mechanisms). For example, these drugs have been shown to adjust (modulate) the activity of the nerves and to have analgesic (pain-relieving) effects as well.
Commonly used psychotropic drugs include the tricyclic antidepressants, desipramine (Norpramine) and trimipramine (Surmontil). Although studies are encouraging, it is not yet clear whether the newer class of antidepressants, the serotonin-reuptake inhibitors such as fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil), are effective in functional disorders, including indigestion.
Psychological treatments for indigestion
Psychological treatments include cognitive-behavioral therapy, hypnosis, psychodynamic or interpersonal psychotherapy, and relaxation/stress management. Few studies of psychological treatments have been conducted in indigestion, although more studies have been done in IBS. Thus, there is little scientific evidence that they are effective in indigestion, although there is some evidence that they are effective in IBS.
Hypnosis has been proposed as an effective treatment for IBS. It is unclear exactly how effective hypnosis is, or how it works.
Smooth muscle relaxants for indigestion
The most widely studied drugs for the treatment of abdominal pain in functional disorders are a group of drugs called smooth-muscle relaxants.
The gastrointestinal tract is primarily composed of a type of muscle called smooth muscle. (By contrast, skeletal muscles such as the biceps are composed of a type of muscle called striated muscle.) Smooth muscle relaxant drugs reduce the strength of contraction of the smooth muscles but do not affect the contraction of other types of muscles. They are used in functional disorders, particularly IBS, with the assumption (not proven) that strong or prolonged contractions of smooth muscles in the intestine-spasms-are the cause of the pain in functional disorders. There are even smooth muscle relaxants that are placed under the tongue, as is nitroglycerin for angina, so that they may be absorbed rapidly.
There are not enough studies of smooth muscle relaxants in indigestion to conclude that they are effective at reducing pain. Since their side effects are few, these drugs probably are worth trying. As with all drugs that are given to control symptoms, patients should carefully evaluate whether or not the smooth muscle relaxant they are using is effective at controlling the symptoms. If it is not clearly effective, the option of discontinuing the relaxant should be discussed with a physician.
Commonly used smooth muscle relaxants are hyoscyamine (Levsin, Anaspaz, Cystospaz, Donnamar) and methscopolamine (Pamine, Pamine Forte). Other drugs combine smooth muscle relaxants with a sedative chlordiazepoxide hydrochloride and clidinium bromide (Donnatal, Librax), but there is no evidence that the addition of sedatives adds to the effectiveness of the treatment.
Which specialties of doctors treat indigestion (dyspepsia)?
Since indigestion is very common, almost all doctors see and treat patients with indigestion, especially family practitioners, internists and even pediatricians. If these generalists are unable to provide adequate treatment, the patient usually is referred to a gastroenterologist, an internist or pediatrician with specialty training in gastrointestinal diseases.
What are the complications of indigestion (dyspepsia)?
The complications of functional diseases of the gastrointestinal tract are relatively limited. Since symptoms are most often provoked by eating, patients who alter their diets and reduce their intake of calories may lose weight. However, loss of weight is unusual in functional diseases. In fact, loss of weight should suggest the presence of non-functional diseases. Symptoms that awaken patients from sleep also are more likely to be due to non-functional than functional disease.
Most commonly, functional diseases interfere with patients' comfort and daily activities. Individuals who develop nausea or pain after eating may skip breakfast or lunch because of the symptoms they experience. Patients also commonly associate symptoms with specific foods (for example, milk, fat, vegetables). Whether or not the associations are real, these patients will restrict their diets accordingly. Milk is the most common food that is eliminated, often unnecessarily, and this can lead to inadequate intake of calcium and osteoporosis. The interference with daily activities also can lead to problems with interpersonal relationships, especially with spouses. Most patients with functional disease live with their symptoms and infrequently visit physicians for diagnosis and treatment.
What can a person expect during the diagnosis and treatment of indigestion (prognosis)?
The initial approach to dyspepsia, whether it be treatment or testing, depends on the patient's age, symptoms and the duration of the symptoms. If the patient is younger than 50 years of age and serious disease, particularly cancer, is not likely, testing is less important. If the symptoms are typical for dyspepsia and have been present for many years without change, then there is less need for testing, or at least extensive testing, to exclude other gastrointestinal and non-gastrointestinal diseases.
On the other hand, if the symptoms are of recent onset (weeks or months), progressively worsening, severe, or associated with "warning" signs, then early, more extensive testing is appropriate. Warning signs include loss of weight, nighttime awakening, blood in the stool or the material that is vomited (vomitus), and signs of inflammation, such as fever or abdominal tenderness. Testing also is appropriate if, in addition to symptoms of dyspepsia, there are other prominent symptoms that are not commonly associated with dyspepsia.
If there are symptoms that suggest conditions other than dyspepsia, tests that are specific for these diseases should be done first. The reason is that if these other tests disclose other diseases, it may not be necessary to do additional testing. Examples of such symptoms and possible testing include:
- Vomiting: upper gastrointestinal endoscopy to diagnose inflammatory or obstructing diseases; gastric emptying studies and/or electrogastrography to diagnose impaired emptying of the stomach.
- Abdominal distention with or without increased flatulence: upper gastrointestinal and small intestinal x-rays to diagnose obstructing diseases; hydrogen breath testing to diagnose bacterial overgrowth of the small intestine.
For a patient with typical symptoms of dyspepsia who requires testing to exclude other diseases, a standard screening panel of blood tests would reasonably be included. These tests might reveal clues to non-gastrointestinal diseases. Sensitive stool testing (antigen/antibody) for Giardia lamblia would be reasonable because this parasitic infection is common and can be acute or chronic. Some physicians do blood testing for celiac disease (sprue), but the value of doing this is unclear. Moreover, if an EGD is planned, biopsies of the duodenum usually will make the diagnosis of celiac disease. A plain X-ray of the abdomen might be done during an episode of abdominal pain (to look for intestinal blockage or obstruction). Testing for lactose intolerance or a trial of a strict lactose-free diet should be considered. The physician's clinical judgment should determine the extent to which initial testing is appropriate.
Once testing has been done to an extent that is appropriate for the clinical situation, it is reasonable to first try a therapeutic trial of stomach acid suppression to see if symptoms improve. Such a trial probably should involve a PPI (proton pump inhibitor) for 8 to 12 weeks. If there is no clear response of symptoms, the options then are to discontinue the PPI or confirm its effectiveness in suppressing acid with 24 hour acid testing. If there is a clear and substantial decrease in symptoms with the PPI, then decisions need to be made about continuing acid suppression and which drugs to use.
Another therapeutic approach is to test for Helicobacter pylori infection of the stomach (with blood, breath or stool tests) and to treat patients with infection to eradicate the infection. It may be necessary to retest patients after treatment to prove that treatment has effectively eradicated the infection, particularly if dyspeptic symptoms persist after treatment.
If treatment with a PPI has satisfactorily suppressed acid according to acid testing (or acid suppression has not been measured) and yet the symptoms have not improved, it is reasonable to conduct further testing as described above. Esophago-gastro-duodenoscopy, or EGD, (and, possibly, colonoscopy) would be the next consideration, probably with multiple biopsies of the stomach and duodenum (and colon if colonoscopy is done). Finally, small intestinal x-rays and an ultrasound examination of the gallbladder might be done. An abdominal ultrasound examination, CT scan, or MRI scan can exclude non-gastrointestinal diseases. Once appropriate testing has been completed, empiric trials of other drugs (for example, smooth muscle relaxants, psychotropic drugs, and promotility drugs) can be done. (An empiric trial of a drug is a trial that is not based on an understanding of the exact cause of the symptoms)
If all of the appropriate testing reveals no disease that could be causing the symptoms and the dyspeptic symptoms have not responded to empiric treatments, other, more specialized tests should be considered. These tests include hydrogen breath testing to diagnose bacterial overgrowth of the small intestine, gastric emptying studies, EGG, small intestinal transit studies, antro-duodenal motility and barostatic studies, and possibly capsule endoscopy. These specialized studies probably should be done at centers that have experience and expertise in diagnosing and treating functional diseases.
What other diseases or conditions mimic indigestion (dyspepsia)?
Exclusion of non-functional gastrointestinal disease
As always, a detailed history from the patient and a physical examination frequently will suggest the cause of dyspepsia. Routine screening blood tests often are performed looking for clues to unsuspected diseases. Examinations of stool also are a part of the evaluation since they may reveal infection, signs of inflammation, or blood and direct further diagnostic testing. Sensitive stool testing (antigen/antibody) for Giardia lamblia would be reasonable because this parasitic infection is common and can be acute or chronic. Some physicians do blood testing for celiac disease (sprue), but the value of doing this is unclear. (Moreover, if an EGD is planned, biopsies of the duodenum usually will make the diagnosis of celiac disease.) If bacterial overgrowth of the small intestine is being considered, breath hydrogen testing can be considered.
There are many tests to exclude non-functional gastrointestinal diseases. The primary issue, however, is to decide which tests are reasonable to perform. Since each case is individual, different tests may be reasonable for different patients. Nevertheless, certain basic tests are often performed to exclude non-functional gastrointestinal disease. These tests identify anatomic (structural) and histological (microscopic) diseases of the esophagus, stomach, and intestines.
Both X-rays and endoscopies can identify anatomic diseases. Only endoscopies, however, can diagnose histological diseases because biopsies (samples of tissue) can be taken during the procedure. The X-ray tests include:
- The esophagram and video-fluoroscopic swallowing study for examining the esophagus
- The upper gastrointestinal series for examining the stomach and duodenum
- The small bowel series for examining the small intestine
- The barium enema for examining the colon and terminal ileum.
- The computerized tomography (CT) scan for examining the small intestine
The endoscopic tests include:
- Upper gastrointestinal endoscopy (esophago-gastro-duodenoscopy or EGD) to examine the esophagus, stomach and duodenum
- Colonoscopy to examine the colon and terminal ileum
- Endoscopy also is available to examine the small intestine, but this type of endoscopy is complex, not widely available, and of unproven value in indigestion.
For examination of the small intestine, there is also a capsule containing a tiny camera and transmitter that can be swallowed (capsule endoscopy). As the capsule travels through the intestines, it transmits pictures of the inside of the intestines to an external recorder for later review. The capsule is not widely available and its value, particularly in indigestion, has not yet been proven.
Newer endoscopes, similar to those used for EGD and colonoscopy are available that allow the entire small intestine to be examined. Unlike the capsule, however, the endoscope has channels in it that allow instruments to be passed into the intestine to collect samples of tissue (biopsies) and to treat abnormal findings such as polyps.
X-rays are easier to perform and less costly than endoscopies. The skills necessary to perform gastrointestinal X-rays, however, are becoming rare among radiologists because they are doing them less often. Therefore, the quality of the X-rays often is not as high as it used to be, and, as a result, CT scans of the small intestine are replacing small intestinal X-rays. As noted previously, endoscopies have an advantage over X-rays since at the time of endoscopies, biopsies can be taken to diagnose or exclude histological diseases, something that X-rays cannot do.
Exclusion of acid-related gastrointestinal diseases
Because they are so common, the most important non-functional gastrointestinal diseases to exclude are acid-related diseases that cause inflammation and ulceration of the esophagus, stomach, and duodenum. Infection of the stomach with Helicobacter pylori, an infection that is closely associated with some acid-related diseases, is included in this group. It is not clear, however, how often Helicobacter pylori causes indigestion. Moreover, the only way of excluding this bacterium as a cause of indigestion in a particular patient is by eliminating the infection (if it is present) with appropriate antibiotics. If indigestion is substantially improved by eradication, it is likely that the bacterium was responsible. Helicobacter pylori infection also can be diagnosed (or excluded) by blood tests, biopsy of the stomach, urea breath test, or a stool test.
Endoscopy is a good way of diagnosing or excluding acid-related inflammation. If no signs of inflammation are present, acid-related diseases are unlikely. Nevertheless, many patients without signs of inflammation respond to potent and prolonged suppression of acid, suggesting that acid is causing their indigestion. Therefore, many physicians will use potent suppression of acid in indigestion as a means to both treat and diagnose. Thus, if indigestion improves substantially (more than 50% to 75%) with suppression of acid, they consider it likely that acid is responsible for the indigestion. For this purpose, it is important to use potent acid suppression with proton pump inhibitors (PPIs), such as:
- omeprazole (Prilosec, Zegerid)
- lansoprazole (Prevacid)
- rabeprazole (Aciphex)
- pantoprazole (Protonix)
- esomeprazole (Nexium)
- dexlansoprazole (Dexilant)
Treatment often is given at higher than recommended doses for 12 weeks or more before a decision is made about the effect of treatment on the symptoms. (A short course for just a few days or weeks is not enough.) If the symptoms of indigestion do not improve, it even may be reasonable to check the amount of acid produced by the stomach (and also the reflux of acid into the esophagus) by 24 hour pH monitoring to be certain that the acid-suppressing drugs are effectively suppressing acid. (Up to 10% of patients are resistant to the effects of even the PPIs.)
Exclusion of non-gastrointestinal disease
Patients with indigestion often undergo abdominal ultrasonography (US), computerized tomography (CT or CAT scans), or magnetic resonance imaging (MRI). These tests are used primarily to diagnose non-intestinal diseases. (Although the tests also are capable of diagnosing intestinal diseases, their value for this purpose is limited. X-ray and endoscopy are better.) It is important to realize that US, CT, and MRI are powerful tests and may uncover abnormalities that are unrelated to indigestion. The most common example of this is the finding of gallstones that, in fact, are causing no symptoms. (At least up to 50% of gallstones cause no symptoms.) This can cause a problem if the gallstones are assumed to be causing the indigestion. Surgical removal of the gallbladder with its gallstones (cholecystectomy) is unlikely to relieve the indigestion. (Cholecystectomy would be expected to relieve only the characteristic symptoms that gallstones can cause.) Additional tests to exclude non-gastrointestinal diseases may be appropriate in certain specific situations, although certainly not in most patients.
Exclusion of psychiatric disease
The possibility of psychiatric (psychological or psychosomatic) illness often arises in patients with indigestion because the symptoms are subjective and no objective abnormalities can be identified. Psychiatric illness may complicate indigestion, but it is unclear if psychiatric illness can cause indigestion. If there is a possibility of psychiatric illness, a psychiatric evaluation is appropriate, and psychiatric treatment may improve (though probably not cure) the symptoms.
What research is ongoing for treatments to cure indigestion (dyspepsia)?
The future of dyspepsia will depend on our increasing knowledge of the processes (mechanisms) that cause dyspepsia. Acquiring this knowledge, in turn, depends on research funding. Because of the difficulties in conducting research in dyspepsia, this knowledge will not come quickly. Until we have an understanding of the mechanisms of dyspepsia, newer treatments will be based on our developing a better understanding of the normal control of gastrointestinal function, which is proceeding more rapidly. Specifically, there is intense interest in intestinal neurotransmitters, which are chemicals that the nerves of the intestine use to communicate with each other. The interactions of these neurotransmitters are responsible for adjusting (modulating) the functions of the intestines, such as contraction of muscles and secretion of fluid and mucus.
5-hydroxytriptamine (5-HT or serotonin) is a neurotransmitter that stimulates several different receptors on nerves in the intestine. Examples of experimental drugs for intestinal neurotransmission are sumatriptan (Imitrex) and buspirone (Buspar). These drugs are believed to reduce the responsiveness (sensitivity) of the sensory nerves to what's happening in the intestine by attaching to a particular 5-HT receptor, the 5-HT1 receptor. The 5-HT1 receptor drugs, however, have received only minimal study so far and their role in the treatment of dyspepsia, if any, is unclear.
Promotility drugs similar to cisapride, as previously discussed, are being pursued actively.
Another area of active research is relaxation of the muscles of the stomach for the treatment of dyspepsia. Normally when food enters the stomach, the stomach relaxes to accommodate the food and the secretions it stimulates. Many patients with dyspepsia have been found to have reduced relaxation of the stomach when food enters, and it is possible that this results in discomfort. Drugs that specifically relax the muscles of the stomach are being developed, but more clinical trials showing their benefit are needed.
REFERENCES:Longstreth, GF, MD. Patient education: Upset stomach (functional dyspepsia) in adults (Beyond the Basics). UpToDate. Updated: Feb 2018.
Tack, M. et al. "Functional Dyspepsia." Curr Opin Gastroenterol. 2011;27(6):549-557.