Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is defined as a condition persisting at least three months that is characterized by altered bowel habits and abdominal pain or discomfort relieved by passing stool or release of gases.
IBS is considered a functional bowel disorder but it can seriously impair quality of life due to its impact on social life, daily activities and diet. It is one of the most common gastrointestinal (GI) diseases in the industrialized world yet it still lacks specific histopathological, biochemical or imaging findings that establish diagnostice criteria.
The diagnosis of IBS can be difficult due to a lack of specific tests for confirmation and becauses of a multitude of other conditions that mimic or overlap with those of IBS. While imperfect, there are a number of treatments available for IBS including some new approaches described below.
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Irritable Bowel Syndrome (IBS)
Symptoms of IBS
The main symptoms of IBS include sensation of incomplete or painful defecation, urgent need to defecate, bloating, abdominal cramps and distention, diarrhea and constipation, and rectal spasms. Among these symptoms, abdominal pain is the most disruptive and is found in almost all IBS patients. Certain patients show a higher sensitivity to specific symptoms such as distension of the bowel wall or rectum (see Central Sensitization).
IBS is associated with irregular but frequent urges to defecate and altered stool consistency that switches between softer and harder stool forms. People with IBS often lack the feeling of complete emptying after a bowel movement.
IBS patients may also experience extra-intestinal symptoms including back, head, joint and muscle pain, palpitations, urinary frequency, menstrual irregularities, sleep disturbances and depression. At least 50% of patients have one or more comorbid conditions such as fibromyalgia or interstitial cystitis.
Types or Classifications of IBS
IBS can be characterized by having mostly diarrhea (IBS-D), mostly constipation (IBS-C), or mixed (IBS-M). The diarrhea-predominant subtype of IBS, is characterized by loose (mushy) or watery stools occurring in >25% and by hard or lumpy stools in <25% of bowel movements. IBS-D patients do not have upper GI symptoms as often as people with IBS-C.
The constipation-predominant subtype of IBS, is characterized by hard or lumpy stools occurring in >25% and loose (mushy) or watery stools occurring in <25% of bowel movements.
The prevalence of IBS varies depending on the region, with a global prevalence of 11%. It occurs in 10 to 20% of the Western world and 11% in Australia. Compared with the Western countries, Southeast Asia and especially China have low prevalences of IBS, which lie between 5 and 7% and India has the lowest prevalence of IBS (4.2%).
There are a number of risk factors for IBS and it is believed that having multiple risk factors potentiates the likelihood of developing IBS. Important risk factors include a family history of IBS, female gender and history of hysterectomy. Stress, anxiety and depression also appear to be important risk factors.
There is an association between IBS and sexual, emotional or verbal abuse in childhood or adulthood. Malnutrition may play a role. Also, a history of previous bacterial gastroenteritis has been shown to be a major independent risk factor for the development of IBS.
Psychosomatic disorders often accompany IBS but they are not considered to be causes, but rather the consequences of IBS. These disorders can sometimes intensify patients’ perception of the severity of their abdominal symptoms.
Possible Causes and Contributing Factors to IBS
As a functional disease, IBS is believed to be multi-factorial in terms of causes and contributing factors with no single causative entity identified. Inflammation is thought to play a role as well as central sensitivity, diet, emotion, stress and dysregulation of intestional motility.
Genetic factors are thought to play a minor, but contributory role. They may involve both DNA genes and epigenetic mechanisms (those mechanisms that turn DNA genes on or off). Because genetic factors can promote post-infectious IBS it is believed that genetic variants affect the immune response to bacteria in the gastrointestinal tract and these variants may play a role in the development of symptoms.
Disturbances in the intestinal bacterial colonization
At birth, the GI tract is not yet colonized by bacteria. After birth, the first bacteria, fungi and protozoa introduced orally can reach and colonize the intestine, contributing to a microbial intestinal balance that stabilizes over time. During this time different bacterial populations are introduced into the intestinal tract through daily food intake creating variations in the composition of the bacterial strains. The complex bacterial system that makes up the “microbiome” of the intestinal tract consists of about 100 trillion bacteria. Variations of the microbiome can affect intestional functions which may in turn contribute to the basis for the development of IBS. It has been shown that the fecal microbiome is altered in IBS patients.
Gastrointestinal infections may induce changes in the bacterial colonization of the intestines and if these change persist they may contribute to the development of IBS. Different bacterial products can affect the motility and secretions of the gut. For example, changse in the bacterial balances of E. coli, Lactobacilli and Bifidobacteria are present in the IBS diarrhea-type.
About 20-35 per cent of all cases of IBS develop following a gastrointestinal (GI) infection, contributing to a six times greater risk of developing IBS following a GI infection. These post-infectious forms of IBS have suggested new concepts regarding the nature of IBS, with both post-infectious overgrowth of intestinal bacterial and post-infectious alteration of intestinal permeability (Leaky Gut) now believed to be significant contributors to IBS.
SIBO (Small Intestinal Bacterial Overgrowth)
Overgrowth of bacterial can occur in the upper part of the small bowel and can be caused by altered intestinal contractions, altered gastric acid secretion, blind loops, and partial obstruction. Whether SIBO plays a role in IBS is not quite clear but the frequency of SIBO in IBS patients can be as high as 78%. An association between SIBO and IBS seems likely and is currently being investigated.
When the integrity of the intestinal lining is compromised, the permeability of the gut is altered which allows substances to penetrate the lining of the gut and enter the blood stream, a condition referred to as “leaky gut.” The “inappropriate” entry of these substances is thought to possibly trigger inflammation and the immune system in ways that contribute to the symptoms of IBS.
See “Leaky Gut“
Interactions with the Nervous System
The central nervous system (CNS) can affect many aspects of the GI tract, such as bowel movements, the perception of intestinal pain, and illness-related behavior. Because of the direct connection between the GI tract and the nervous system, GI function can be markedly impacted by the emotional state of an individual, especially those with depression and/or stress. Additionally, the enteric nervous system within the GI tract can contribute to malfunctions at the local level.
Altered sensory processing in the CNS, or “central sensitization,” is believed to occur in IBS and is likely related to the impact of emotional stress. In IBS, this altered processing results in hypersensitivity to bowel symptoms, especially pain. The intestinal pain of IBS is referred to as “visceral” pain, or pain that arises from body organs such as the pancreas, bladder and uterus. Like other types of pain, visceral pain is magnified in the presence of central sensitiviy but visceral pain is also particularlly influenced by emotion and stress. Therefore, daily thought processing, emotional feelings and behaviors may influence visceral pain and as a result many activities may be avoided in attempts to reduce pain.
See: Visceral Pain
IBS and Central Sensitivity
Central sensitivity (CS) is a condition associated with many, if not most, chronic pain conditions. It is characterized by heightened sensitivity to pain as well as other sensory experiences. The hallmarks of CS are hyperalgesia (when a painful sensation is perceived with excessive severity compared to the normal, expected degree of pain) and allodynia (when a sensory experience not normally painful is experienced as painful). In IBS the heightened sensitivity to colonic and rectal distension and contractions are manifestations of CS and hyperalgesia.
IBS patients exhibit a wide variety of extraintestinal symptoms (back pain, migraine headaches, heartburn and muscle pain), consistent with central sensitization. IBS shares similarities with other functional pain conditions, such as fibromyalgia, whiplash, and endometriosis that also demonstrate central sensitization. As such, treatment of IBS must also engage treatment directed at central sensitization.
(see: Central Sensitization)
Diagnosis of IBS
A diagnosis of IBS should be considered only if the person has abdominal pain or discomfort that is either relieved by defecation or associated with altered bowel frequency or stool form. This should be accompanied by at least two of the following four symptoms:
- Altered stool passage (straining, urgency, incomplete evacuation)
- Abdominal bloating (more common in women than men), distension, tension or hardness
- Symptoms made worse by eating
- Passage of mucus in the stool.
Other features such as lethargy, nausea, backache and bladder symptoms are common in people with IBS, and may be used to support the diagnosis.
The diagnosis of IBS can be difficult and it is often misdiagnosed. One must first exclude infections, food intolerances, inflammatory diseases, gastrointestinal tumours, side effects of drugs (antibiotics, tricyclic antidepressants, proton pump inhibitors, etc.) and secondary small intestinal bacterial overgrowth, diverticula, intestinal stenosis, ileocecal resection and immunological disorders.
Food Sensitivities & Intolerances
Intake of specific foods is not considered to cause IBS but certain foods can definitely trigger exacerbations of IBS in some individuals. Foods commonly associated with triggering IBS exacerbations include high-fat fast foods, processed meat, whole grains, sweets, citrus fruit, garlic and onions.
Dietary manipulation with avoidance of specific foods offers improvement for up to two-thirds of people suffering from IBS. Certain food sensitivities and intolerances can mimic the symptoms of IBS and these diagnoses should be excluded before establishing the diagnosis of IBS. Testing for Celiac disease (gluten hypersensitivity), a potentially serious condition, is an important first step for those with symptoms of IBS.
See: IBS and Diet
Evaluation of other forms of gluten sensitivity (non-celiac gluten sensitivity) and food intolerances such as lactose and FODMAPS (Fermentable Oligo-Di-Mono saccharides And Polyols) should also be engaged to determine their possible role in any symptoms attributed to possible IBS.
See:Food Intolerance and Sensitivity
IBS symptoms and symptoms associated with fibromyalgia (FM) are often similar and often misdiagnosed. Neither condition is well understood as to their specific causes and treatment of either condition is often unsatisfactory.
It has been found that up to 72% of people with FM also have symptoms of IBS. Alternatively, up to 32% of people with IBS have FM. There is clearly an overlap in these conditions and it is sometimes related to diet, including sensitivity to gluten and FODMAPs. Avoidance of ingesting FODMAPs in both those with IBS as well as those with FM may provide a significant reduction in the GI symptoms common to these two conditions. Up to 75% of those who suffer IBS will benefit from dietary restriction of FODMAPs with improvement of gas, bloating, abdominal pain, and change in bowel habits.
In a study evaluating FM patients with IBS, a one-year gluten-free diet resulted in a 26-29% reduction in FM symptoms. As noted below, some foods (including wheat, barley and rye flours) contain both FODMAPs and gluten.
See: Diet & Fibromyalgia
Management of IBS
Symptomatic treatment of IBS is generally directed at bowel function and pain. But the nature of IBS is such that an integrative approach that incorporates multiple modalities including lifestyle & dietary changes is most likely to be successful.
Currently available medications provide symptomatic relief at best and have been shown to be only slightly more effective than placebos. Pharmacologic options for managing gut motility are commonly employed.
Dietary modification can be particularly important for some, reduction and management of anxiety and stress is pivotal as well as the treatment of comorbid depression. Addressing the leaky gut is gaining more attention as an effective treatment option fof IBS.
Lifestyle Changes – Exercise
While specific recommendations for exercise related to managing IBS are largely lacking, an active lifestyle including regular exercise is encouraged for managing IBS. Active living recommendations as they apply to general health and IBS include the following:
A. For general health benefit, adults should achieve a total of at least 30 minutes a day of at least moderate intensity physical activity on 5 or more days of the week.
B. The recommended levels of activity can be achieved either by doing all the daily activity in one session, or through several shorter bouts of activity of 10 minutes or more. The activity can be lifestyle activity or structured exercise or sport, or a combination of these.
C. More specific activity recommendations are advised for individual diseases and conditions. For many people, 45-60 minutes of moderate intensity physical activity a day is necessary to manage obesity. For bone health in osteopenia, activities that produce high physical stresses on the bones may be necessary.
Lifestyle Changes: Stress Reduction, Hypnosis & Meditation
Due to the impact of anxiety and stress on the presence and severity of symptoms of IBS, lifestyle changes to reduce these conditions is emphasized. Engaging hypnosis, meditation, stress reduction techniques and other mindful exercises have been shown to be effective.
Psychological stressors can result in intestinal symptoms by producing changes in intestinal function mediated by the autonomic nervous system, hypothalamic-pituitary-adrenal axis and/or immune system. Higher brain centers including the emotional system can also influence this process, through modulation of nerve networks involved in brain-gut communication.
Heightened stress perception can trigger a hypervigilance toward bodily sensations that may magnify the severity and impact of the symptoms on quality of life. The use of cognitive behavior training can be helpful in reversing hypervigilance. There is good evidence for the benefit of practicing self-hypnosis techniques to reduce stress and its impact on IBS symptoms.
See Using the Mind
Lifestyle Changes: Diet
With regard to diet and IBS, some general recommendations can be advised:
(1) Have regular meals and take time to eat, allowing at least 15 minutes per meal.
(2) Avoid missing meals or leaving long gaps between eating.
(3) Drink at least eight cups of fluid per day, especially water or other non-caffeinated drinks, including herbal teas.
(4) Restrict black tea and coffee to three cups per day.
(5) Limit intake of alcohol and carbonated drinks to one or two per day.
(6) It may be helpful to limit intake of high-fiber food (such as wholemeal or high-fiber flour and breads, cereals high in bran, and whole grains such as brown rice).
(7) Reduce intake of ‘resistant starch’ (starch that resists digestion in the small intestine and reaches the colon intact), which is often found in processed or re-cooked foods.
(8) Limit fresh fruit to three portions per day (a portion should be approximately 80z).
(9) People with diarrhea should avoid sorbitol, an artificial sweetener found in sugar-free sweets (including chewing gum and drinks) and in some diabetic and slimming products.
(10) People with wind and bloating may find it helpful to eat oats (such as oat-based breakfast cereal or porridge) and linseeds (up to one tablespoon per day).
As noted above, dietary sensitivities and intolerances may play a significant role in the symptoms of IBS. Individual assessments for these conditions is the first step in both the diagnosis and the treatment of IBS.
There are two types of fiber:
(1) Insoluble fibre (corn, wheat, fruit and vegetables)
(2) Soluble fibre (pectins, fruit and vegetables, oats, nuts and seeds and psyllium)
Dietary fiber intake has been evaluated as a means of intervening to improve the variety of symptoms related to IBS including abdominal pain, bloating, flatulence as well as constipation and diarrhea. However, due to only weak evidence of benefit, high fiber diets are not generally recommended in IBS but should be tailored to the individual. Overall, it may be preferential for the dietary fiber intake in IBS to be closer to 12g/day rather than 30g/day as generally recommended.
If an increase in fiber is needed, it should be in the form of soluble fiber. Oats, which are high in soluble fiber, are particularly recommended due to their additional protective effect on cholesterol levels. Wheat bran on the other hand is high in insoluble fiber for which there is little evidence of benefit but clear evidence that it may worsen IBS symptoms. Wheat contains both glutens and FODMAPs, agents known to be associated with intolerance or sensitivity in many patients with IBS.
The protective effect of fiber should be sought from food rich in dietary fiber which contains other nutrients and phytochemicals as opposed to supplemental fiber alone.
Aloe Vera has been recommended for treating the symptoms of IBS but research indicates that people should be discouraged from the use of aloe vera in the treatment of IBS. Not only do studies indicate aloe vera to be ineffective but it can cause abdominal cramps and diarrhea. Other adverse effects include low blood sugar levels and electrolyte imbalance, particularly lowered potassium levels.
Recent research has suggested that there may be a role for the use of probiotics in the management of IBS. The definition of “probiotic” is: “Live microorganisms that confer a health benefit on the host when administered in adequate amounts.” Probiotics stimulate the growth of other microorganisms and supplement the body’s naturally occurring gut microbiota.
The potential benefits of probiotics in the treatment of IBS include restoring the balance of the normal intestinal microflora, the production of agents that inhibit pathologic bacteria and they may provide relief of bloating, flatulence and distension. Probiotics may inhibit the development of IBS following bacterial gastroenteritis and they may improve lactose intolerance.
New evidence links IBS with the intestinal microbiota:
(i) IBS patients have differences in their luminal and mucosal-associated intestinal flora (bacteria) when compared with those without IBS;
(ii) new-onset IBS symptoms develop in about 30% of people following recovery from infectious gastroenteritis,
(iii) small bowel bacterial overgrowth has been reported in a proportion of IBS patients and
(iv) certain antibiotics such as rifaximin relieve IBS symptoms in some individuals.
The research findings relative to the benefit of probiotics in the management of IBS remain somewhat inconsistent, recommendations from the American College of Gastroenterology (ACG) and expert panels from both Europe and the USA have concluded that there is a reasonable rationale for the benefit of probiotics as a treatment for the symptoms of IBS. While probiotics are currently gaining considerable interest regarding the treatment of IBS, it is important to emphasize that only certain probiotic strains may be beneficial.
The evidence of benefit is not present for all probiotics but the species of lactobacilli and Bifidobacteria have good evidence of support, and certain combinations of probiotics appear to be of use. People with IBS who choose to try probiotics should be advised to take the product for at least 4 weeks while monitoring the effect. Probiotics should be taken at the dose recommended by the manufacturer.
- Anti-motility agents
- Antidepressants: tricyclics, SNRIs and SSRI’s
The abdominal pain, bloating and gas in IBS may be a result of the irregular and intermittent intestinal contractions along the length of the colon. Pain is most common after a meal and may last for several hours. Antispasmodics may relieve the pain associated with IBS.
Antispasmodics can be divided into two main categories: antimuscarinics and smooth muscle relaxants. Antimuscarinics reduce intestinal contractions and movement of food throught the intestinal tract. Smooth muscle relaxants directly relax intestinal smooth muscle. The use of antispasmodics is primarily to relax the smooth muscles of the gut, helping to prevent or relieve the painful cramping spasms in the intestines. They are typically taken 30 to 45 minutes before meals and can be effective in some individuals.
Commonly available antispasmodics:
(1) Atropine (synonyms: hyoscyamine)
(2) Dicyclomine (trade name: Bentyl)
(3) Hyoscine (synonym: scopolamine; trade name: Transcop®)
(4) Hyoscine butylbromide (synonym: scopolamine butylbromide; trade name: Buscopan)
(4) Propantheline (trade name: Pro-Banthine®)
Direct-action smooth muscle relaxants:
(2) Mebeverine (Trade name: Colofac®)
(3) Peppermint oil (Trade names: Colpermin®; Mintec®).
Authoritative guidelines indicate that all the antispodics (hyoscine, mebeverine, peppermint oil, dicycloverine, alverine) are cost-effective for long-term maintenance use in individuals with IBS. Atropine, however, lacked definitive benefit and is not recommended.
It is generally believed that treatment of constipation with IBS is different from treatment of simple constipation. People with IBS cannot cope with gas and some laxatives increase gas and worsen IBS symptoms, lactulose in particular. IBS patients should be actively discouraged from taking lactulose.
The best practice of using laxatives is to titrate the dose of laxative to optimise symptoms. The route of adminstration for laxatives may be oral or rectal. Laxatives can be used in two ways: as short-term rescue medication or as longer-term maintenance treatment. There is no evidence that long term laxative use damages the bowel.
Laxatives can be separated into four main categories: bulk forming laxatives; stool softeners: osmotic laxatives and stimulant laxatives. Bulk-forming laxatives relieve constipation by increasing stool mass, which stimulates intestinal contractions but adequate fluid intake must be maintained to avoid intestinal obstruction. Stool softeners may lubricate the passage of stools and/or soften them. Osmotic laxatives increase the amount of water in the large bowel, either by drawing fluid from the body into the bowel or by retaining the fluid with which they were administered. Stimulant laxatives work by directly increasing intestinal contractions, but they often cause abdominal cramps.
Laxatives such as polyethylene glycol (PEG), bisacodyl and sodium picosulfate have been shown to be safe and effective for long-term maintenance use in individuals with IBS.
Antimotility agents are used for the management of diarrhea by reducing intestinal contractions. Common antimotility agents include:
(1) Diphenoxylate and atropine mixture (Trade name: Lomotil®)
(2)Loperamide hydrochloride (Trade name: Imodium®) & Loperamide hydrochloride and simeticone (Trade name: Imodium® Plus)
(3) Opioids: codeine, morphine
Of these agents, loperamide is the preferred choice. It is more effective than lomotil and avoids the dependency and abuse potentials of opioids.
Tricyclics and Antidepressants
Antidepressants have been used for the last fifty years in a variety of gastrointestinal (GI) conditions and have been increasingly used in the treatment of functional GI disorders such as IBS. While anxiety and depression are common in patients with severe IBS and may be present to some degree in all IBS patients, antidepressants appear have a pain benefit separate from their antidepressant effect. In visceral pain syndromes such as IBS, antidepressants modify the interactions between the central and enteric nervous systems which can reduce pain.
Tricyclic antidepressants also have a peripheral anticholinergic action that reduces intestinal contractions and abdominal cramping pains. Commonly used tricyclic antidepressants include amitriptyline (Elavil), doxepine and desipramine.
IBS – Overview
- Irritable bowel syndrome in adults – Diagnosis and management of irritable bowel syndrome in primary care – 2008
- Irritable-bowel-syndrome-in-adults-Diagnosis-and-management-of-irritable-bowel-syndrome-in-primary-care update 2017
IBS – Treatment: CAM
IBS – Central Sensitization
- Assessment and manifestation of central sensitisation across different chronic pain conditions – 2018
IBS – Visceral Hypersensitivity
IBS – FODMAPs
- Low FODMAPs diet vs. general dietary advice improves clinical response in patients with diarrhea-predominant irritable bowel syndrome: a randomized… – PubMed – NCBI
- Low-FODMAP Diet Improves Irritable Bowel Syndrome Symptoms – A Meta-Analysis – 2017
- The Low FODMAP Diet – Many Question Marks for a Catchy Acronym – 2017
- Does a diet low in FODMAPs reduce symptoms associated with functional gastrointestinal disorders
IBS – Hypnosis, Meditation & Relaxation Techniques
- Complementary and Alternative Medicine for IBS in Adults
- Stress and visceral pain – from animal models to clinical therapies – 2012
- Body Awareness – a phenomenological inquiry into the common ground of mind body therapies – 2011
- Integrative Medicine for Gastrointestinal Disease. – PubMed – NCBI
- Mindfulness-Based Therapies in the Treatment of Functional Gastrointestinal Disorders – A Meta-Analysis – 2014
IBS – Probiotics
IBS – Red Chillies
- Effect of red chillies on small bowel and colonic transit and rectal sensitivity in men with irritable bowel syndrome – 2002
IBS & FM – FM and Irritable Bowel Syndrome (IBS)
- Effect of one year of a gluten-free diet on the clinical evolution of irritable bowel syndrome plus fibromyalgia in patients with associated lymphocytic enteritis – 2014
- Gluten-free diet in the management of patients with irritable bowel syndrome, fibromyalgia and lymphocytic enteritis – 2014
- The Overlap between Irritable Bowel Syndrome and Non-Celiac Gluten Sensitivity – A Clinical Dilemma – 2015
- Treatment of irritable bowel syndrome with probiotics: growing evidence – 2013
- Irritable bowel syndrome in adults – Diagnosis and management of irritable bowel syndrome in primary care – 2008
Emphasis on Education
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al as well as CAM treatments.< /p>
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