What is Irritable Bowel Syndrome (IBS)? Explained

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The most frequently identified digestive disorder is irritable bowel syndrome (IBS). It is an illness that is diagnosed based on symptoms, such as the presence of stomach pain or discomfort and abnormal bowel habits in the lack of any other disease that would produce similar symptoms.

The burden of Illness and Natural History of Irritable bowel syndrome

Irritable Bowel Syndrome
IBS History

IBS is frequently co-occurring with somatic pain syndromes (fibromyalgia, chronic fatigue syndrome, and chronic pelvic pain), gastrointestinal conditions (dyspepsia, gastroesophageal reflux disease), and psychiatric conditions (major depression, anxiety, and somatization), which suggests that there may be common pathogenesis.

IBS is typically a chronic, recurrent condition with variable symptoms. According to a comprehensive analysis, among IBS patients treated in clinics over a lengthy period, 2% to 18% experienced worsening, 30% to 50% had no change, and 12% to 38% experienced improvement. Worse results were indicated by prior surgery, longer disease duration, higher somatic ratings, and concomitant anxiety and depression. A patient who receives an IBS diagnosis has a less than 5% chance of later acquiring an alternative organic diagnosis after a negative diagnostic evaluation outcome.

IBS substantially lowers productivity at work and quality of life in terms of health. 13% to 88% of persons with IBS seek medical attention. More distress and less social support are experienced by people who seek treatment compared to those who do not. IBS causes 5.9 million prescriptions and 3.1 million ambulatory care visits yearly in the US, costing more than $20 billion in direct and indirect costs.

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Pathophysiology of Irritable bowel syndrome

IBS has a diverse clinical phenotype and a diverse etiology. IBS probably includes several illnesses with different pathophysiologies but similar symptoms. In the last 40 years, a variety of factors have been revealed that affect the pathophysiology of IBS. In the past, anomalies in motility, visceral feeling, brain-gut interaction, and psychosocial distress have been the main focus of research into the pathophysiology of IBS. Although the majority of IBS patients can demonstrate one or more of these anomalies, none of them can explain symptoms in all of them.

Recently, it has been discovered that some IBS patients have altered gut immune activity, intestinal permeability, and intestinal and colonic microbiomes.

The higher prevalence of IBS symptoms in inflammatory illnesses including celiac disease, inflammatory bowel diseases, and severe acute gastroenteritis lends support to the role of these variables.   Some IBS patients have enhanced innate and adaptive immune system activity in their gut mucosa. Patients with IBS-D22 have also been found to have increased small bowel and colonic permeability, which is linked to visceral hypersensitivity. IBS patients have considerably different fecal microbiota from controls, which is probably due to a combination of factors including genetics, nutrition, stress, infection, and medication or antibiotic use.

The so-called postinfectious IBS, or IBS symptoms that appear after acute gastroenteritis, present an intriguing developmental paradigm. Chronic IBS symptoms may be predisposed to host variables like genetics, immunological function, microbiota, and psychological status as well as environmental factors like stress, the severity of an infection, or antibiotic use. Unlike conventional IBS, which tends to be a chronic relapsing syndrome, postinfectious IBS spontaneously cures in around half of the patients within 6 to 8 years of the index infection, making it crucial to identify patients with this condition.

IBS development may also be influenced by psychosocial factors. Verbal, sexual, or physical abuse is more prevalent among women who have IBS, and it is associated with the disease through brain-gut and mucosal immunological dysregulation.   Recurrent stomach pain may start in childhood for certain IBS individuals and signify learned disease habits. 

The brain-gut axis may undergo long-lasting modifications as a result of these events, allowing people to perceive gastrointestinal input and sensations that would otherwise go unnoticed. However, healthy people with regular gut feelings and function hardly ever suffer symptoms after eating.

Symptoms of Irritable bowel syndrome

Irritable Bowel Syndrome
Symptoms of IBS

The following are the symptom of the disease

  • Frequent or loose stools
  • Constipation
  • Bloating
  • abdominal pain, discomfort, or cramping as a result of eating certain foods or having certain food sensitivities
  • Dynamic symptoms that fluctuate over time (such as shifting pain locations or altering stools)

Concerning Organic Disease Symptoms

Symptoms that start around age 50 and are severe or get worse over time

  • Unaccounted-for weight loss
  • Nighttime diarrhea
  • Family history of gastrointestinal disorders, such as inflammatory bowel disease, celiac disease, or colon cancer
  • Blood in the urine or melena
  • unexplained anemia due to a lack of iron

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 A medical history and physical examination are the initial steps in the diagnosis of IBS. You’ll be questioned by your doctor about your symptoms:

  • Do you experience bowel movement pain?
  • Have you noticed a change in how frequently you urinate?
  • Has the appearance of your poop changed?
  • How frequently do your symptoms occur?
  • When did your signs first appear?
  • Which medications are you taking?
  • Have you lately had a difficult situation or a recent illness?

To confirm a diagnosis, you might require additional testing depending on your symptoms. Other conditions that resemble IBS can be ruled out using blood tests, stool samples, and X-rays.

A flexible sigmoidoscopy can be used to assess polyps, rectal bleeding, and bowel problems. Your supplier will

  • A long, thin, flexible instrument called a sigmoidoscope should be inserted into the rectum.
  • To the colon, advance the sigmoidoscope.
  • Look at the lower colon and the rectum’s lining.


What to anticipate during a colonoscopy is listed below. Your supplier will

  • Use the rectum to insert the colonoscope.
  • Expand the scope to the colon’s full extent.
  • Take a biopsy by removing a little amount of tissue (if necessary).
  • Find and remove polyps, which are tiny growths (if necessary).

Frequently, medical professionals can use a colonoscopy to diagnose a patient correctly and even administer medication. Compared to an abdominal operation, a colonoscopy is a far less invasive treatment.

General Management Recommendations

The foundation of managing patients with IBS is a trusted patient-physician connection. Building this relationship can be aided by actively listening, refraining from interruptions, empathetic communication, realistic expectations (helping rather than “curing”), and the use of nonverbal cues including eye contact, nodding, leaning forward, and open body position.  The doctor must be aware of the patient’s visit objectives and refrain from concentrating solely on gastrointestinal problems. The ritual of touch is established during a physical exam, and many patients associate this ritual with a thorough and kind doctor. Assigning a firm diagnosis and imparting knowledge on the causes, natural course, and management of IBS is essential.

Since IBS is a symptom-based condition, treatments can target gastrointestinal symptoms like diarrhea and constipation as well as abdominal symptoms like discomfort, cramping, and bloating. Historically, over-the-counter drugs to treat diarrhea (such as loperamide, probiotics) or constipation have been the primary treatments for IBS (eg, fiber supplements, laxatives). The improvement of altered bowel habits, wide availability, low cost, and stellar safety record are all advantages of this approach. However, over-the-counter drugs don’t help much with general, or all-encompassing, IBS symptoms, or with stomach symptoms like discomfort and bloating.


Physically active people have more frequent bowel movements and faster colon transit than sedentary people.  In addition, randomized clinical research discovered that structured exercise interventions produced better reductions in overall IBS symptoms than standard therapy.  Therefore, it is important to motivate IBS sufferers to improve their physical activity. A straightforward suggestion is to go for a daily 20-minute stroll (around 1 mile). As tolerated, distance and speed can be gradually increased.


Patients frequently link eating a meal to their IBS symptoms. 90% of IBS sufferers restrict their food to lessen or eliminate their symptoms. Real food allergies are rare in IBS patients. On the other hand, reports of food sensitivities or intolerances are common. Emerging research at the moment supports gluten-free diets low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols for IBS patients.

Medical Treatments for IBS


Antidiarr Loperamide, an antidiarrheal drug, inhibits peristalsis, prolongs gastrointestinal transit, lowers fecal volume, and is frequently prescribed as first-line therapy for IBS-D patients. Loperamide did not improve overall IBS symptoms in either of the two randomized trials involving IBS-D and IBS-M patients. However, loperamide can be administered as a preventative measure when a patient is at risk for diarrhea since it lessens bowel frequency and improves stool consistency.

Loperamide is preferred to diphenoxylate or atropine when taken long-term because it does not penetrate the blood-brain barrier and is less likely to develop habituation. In actual practice, many gastroenterologists treat diarrhea with bile acid sequestrants like cholestyramine and colesevelam. With IBS patients, these medications have not been thoroughly tested in randomized trials.

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Serotonin Agents: 5-HT3 Receptor Antagonists

Serotonin, a hormone produced in the gut, affects the visceral and gastrointestinal experience. Women with severe, incapacitating IBS-D who have not responded to conventional medical therapy can now take the 5-HT3 antagonist alostateron. Alosetron (0.5-1 mg once or twice daily) reduces overall and specific IBS-D symptoms in both men and women for up to a year, with a therapeutic advantage of about 15% over placebo. Alosetron’s potential side effects, such as dose-dependent constipation and idiosyncratic ischemic colitis, have prompted the development of a risk management strategy that calls for US patients and prescribers to be aware of the risks before the medication’s dispensation.


Antispasmodics include drugs with anticholinergic or calcium channel blocking properties that may improve IBS symptoms by relaxing gut smooth muscle. Because of its ability to inhibit calcium channels and availability over the counter, peppermint oil is categorized as an antispasmodic. Some IBS patients may benefit from using enteric peppermint oil (187–225 mg, three times daily), according to several modest clinical investigations. 

Although most people tolerate peppermint oil well, some may have reflux symptoms.


Patients with IBS-C are typically prescribed osmotic laxatives, such as polyethylene glycol, as their initial course of treatment. It regularly improves bowel symptoms, such as stool frequency and consistency, according to clinical trials, but does not consistently reduce bloating or pain in the abdomen. With dose escalation determined by clinical response, the typical starting dose is 17 g in juice or water. Although polyethylene glycol is usually well tolerated, it can occasionally result in bloating, gas, and loose stools.

Patients with IBS-C frequently take stimulant laxatives.

We are aware of no randomized, controlled trials in people with IBS-C, even though efficacy has been shown in patients with chronic constipation. Concerning IBS, stomach discomfort and cramps are the most frequent side effects.

Probiotics and Antibiotics

Live bacteria are known as probiotics, and when taken in adequate amounts, they can help the host’s health. Prebiotics are foods, typically carbohydrates, that support the development of probiotic microorganisms. Prebiotic and probiotic supplements are known as synbiotics. Extracts from lysed or dead bacteria make up postbiotics. Probiotics’ effect on IBS has been reviewed using the most reliable evidence. Probiotics as a whole reduced overall IBS symptom such as stomach discomfort, bloating, and gas in a recent meta-analysis that included randomized clinical trials.

A poorly absorbed, broad-spectrum antibiotic called rifaximin has been tested on IBS patients. A recent meta-analysis found therapeutic benefits of 9% to 10% for overall symptoms (odds ratio, 1.57; 95% CI, 1.22-2.01) and bloating in randomized clinical trials that involved mostly non-constipated IBS patients.


Antidepressants are now a common therapy choice for patients with moderate to severe IBS due to their impact on pain perception, mood, and motility. Tricyclic antidepressants, selective serotonin reuptake inhibitors, and, to a lesser extent, selective norepinephrine reuptake inhibitors, have all been studied for their effectiveness in treating IBS patients and show positive results.


IBS continues to be a mysterious source of serious misery, illness, and impairment. Shortly, diagnosing IBS will depend on identifying its distinctive symptoms and ruling out organic disease mimics. It is thought that as research develops, new biomarkers that can either rule in or rule out IBS will make it easier to make a confident diagnosis of IBS. Novel nonpharmacologic and pharmacologic treatments will also be made possible by a better understanding of the pathophysiology of IBS. For the time being, doctors must comprehend the importance of dietary, lifestyle, and behavioral adjustment for IBS, whether or not it’s combined with medication treatments.

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