Irritable Bowel Syndrome (IBS) is characterized by abnormal stooling frequency and consistency along with abdominal pain in the absence of any medical or surgical problem in the gut. About 15% of the population is affected by this problem at some point of time in their life but only 10% of these get a physician consultation. Women are 2-3 times more affected than men. Some coexisting conditions with IBS are chronic fatigue syndrome, painful menstrual bleeding, fibromyalgia, and non-ulcer dyspepsia.
Causes of IBS
The exact cause of this condition is unknown but some factors that have been implicated are biopsychosocial factors, alteration in normal gut flora, and changes in diet. About half of the patients referred to a gastroenterology clinic also have psychiatric illnesses such as anxiety, depression, and neurosis. Some patients cannot tolerate short-chain carbohydrates (fructose, lactose, and sorbitol) collectively called as FODMAPs (fermentable, oligo, di and monosaccharides and polyols). The fermentation of these kinds of foods leads to abdominal bloating, pain, and altered bowel habits.Clinical Features of Irritable Bowel Syndrome
Most patients report recurrent abdominal discomfort that is relieved after passing stool. Due to the accumulation of excessive gases in the gut, abdominal bloating worsens throughout the day. Some patients are frequently constipated while others report frequent diarrhea. Based on that, IBS is classified into two types: constipation-predominant IBS and diarrhea-predominant IBS. Most patients report the passage of mucus in stool but blood in stool is not seen. On physical examination, there is no significant finding except for mild tenderness of the lower abdomen.Diagnosing IBS
The diagnosis of IBS is made after ruling out all pathological conditions that mimic the symptoms of IBS. Complete blood count, fecal calprotectin, and sigmoidoscopy are commonly done and are normal in IBS. If a patient is older than 40 years of age, then a colonoscopy is done to rule out colorectal cancer. Some medical conditions that should be ruled out in patients with diarrhea-predominant IBS include celiac disease, microscopic colitis, lactose intolerance, and parasitic infection (if a patient has recently traveled to developing countries). Clinicians also use ROME III criteria for the diagnosis of IBS.ROME III Criteria for Clinical Diagnosis of IBS
Recurrent abdominal discomfort on at least 3 days per month in the last 3 months, associated with 2 or more of the following:- Onset associated with a change in frequency of stool
- Onset associated with a change in form (consistency) of stool
- Improvement with defecation
Management of Irritable Bowel Syndrome
It is important to reassure people who display IBS symptoms, as many are worried that they might have cancer. The patient should be reassured that this condition is not due to any pathological disease but instead is due to some behavioral and psychosocial factors.Some of the dietary measures that may help include a low FODMAPs diet, a low gluten diet, elimination of lactose from the daily diet, and reducing intake of caffeine, alcohol, and artificial sweeteners, such as sorbitol. Drinking plenty of water to maintain optimum hydration and taking time while eating food is also important.
Probiotic capsules are also effective if taken for several months. Patients who do not respond to the above measures may be prescribed drugs such as amitriptyline or imipramine. For constipation-predominant IBS, 5-HT4 agonist prucalopride, chloride channel activators (Lubiprostone), and the guanylate cyclase-C receptor agonist (linaclotide) have shown to be effective. For intractable cases, psychological interventions should be tried. In patients with difficult-to-treat symptoms, trials of anti-inflammatory agents, such as ketotifen or mesalazine and the antibiotic rifaximin can be considered.