Dr Hitesh Kalita
Irritable bowel syndrome (IBS) is a chronic functional disorder of bowels characterised by abdominal pain and changes in bowel habits. By functional disorder of bowels, we mean that the bowels are structurally normal, the condition is benign and idiopathic (without any specific cause) and that there is just a mild disorder of the function of the bowel, leading to a symptomatic disorder. Abdominal pain and changes in stool are essential, by definition, to label a condition like IBS.
What are the signs and symptoms?
IBS presents with abdominal pain, which is often only mild to moderate in intensity, but distressing enough to disrupt normal life activities. Along with pain, there are changes in stool form and changes in the frequency of passing stool. One can have a diarrhoeal stool, constipation with hard stool or an alternating pattern of diarrheal and hard stool. Pain is often seen to be relieved by passing stool. Only occasionally, one reports pain after passing stool. Other symptoms reported are passing mucus with stool. Bloating and measurable abdomen distension are also present. These symptoms are actual and not imagined. Associated adverse life events, stress, anxiety and depressive disorders are also reported with higher frequency in many people with IBS.
When to consider IBS?
IBS is considered when a person is having abdominal pain with bowel dysfunction, abnormal stool frequency, hard stools, diarrhoea, an urgency to pass stool, excess gas and flatulence. Also, these GI symptoms wax and wane and are exacerbated by psychosocial stress (anxiety and depression). Presence of other functional GI disorders and functional extraintestinal symptoms or syndromes (e.g., fibromyalgia) is also seen with increased frequency.
When to consider a diagnosis?
Persons who are more than 45 years of age and who have anaemia, blood in the stools, unintended weight loss, prominent nocturnal symptoms, fever, abdominal mass or lymphadenopathy, family history of colorectal cancer or inflammatory bowel disease and sudden major change in day and night symptoms, may have other diseases and need more investigations. These are also called alarm features. Currently, for the diagnosis of IBS, ROME IV criterion is accepted. The symptoms should be present for at least six months before a diagnosis of IBS is made. When these criteria are met and there are no alarm features, then minimal investigations are needed.
What causes IBS?
The exact cause of IBS is not known. Causation is thought to be multifactorial. There is evidence that IBS has a slight familial component. In approximately 25% of people, symptoms commence after an episode of infective diarrhoea, called post-infectious diarrhoea. It has been observed that infection and inflammation of bowel lead to change in the normal gut microorganisms and also decreases local gut immunity. It has also been observed in many people that there is a change in the number and type of microorganism in their gut. Many people with IBS have a food sensitivity. These people report that symptoms are triggered by food rich in sugars, spicy or fatty foods, coffee and alcohol. Also, it has been observed that people with IBS have a lower pain threshold, thus experiencing pain with a smaller amount of gas and stool in the bowel. Also, abnormalities of contractions in small and large bowel are seen in some people having IBS.
One of the most accepted theory is called “Disorder of Gut-Brain Axis”. Normally small and large intestine have an independent nervous system and exchanges signals with the brain and signals from the brain are able to modulate the gut nervous system. The gut nervous system controls how the intestine works. So the problems in this gut-brain axis may cause IBS symptoms. This theory also explains how psychosocial stress, anxiety, depression and hormonal changes increase symptoms of IBS.
What are the types of IBS?
IBS is further subclassified based on the type of stool passed by the person. If more than 25% of the stool passed is loose and watery than it is subclassified as IBS-diarrhoea predominant (or IBS-D). If more than 25% of the stool is hard or lumpy, it is subclassified as IBS-constipation predominant (or IBS-C). Sometimes, a person passes both hard and loose stool more than 25% of times then it is subclassified as IBS mixed (or IBS M). These subclassifications help in giving therapy. Ideally, a person needs to be taught to prepare a stool chart according to the Bristol Stool scale for these subclassifications.
Why is managing IBS a challenge?
Studies show that 30-50% of the workload at gastroenterology OPD has IBS. There is a lack of definite laboratory and radiological investigations to diagnose IBS. A gut infection often triggers IBS. A higher than usual frequency of psychological problems in those having IBS may aggravate the problem. Some physicians are of the view that symptoms are just imagined and ignoring the symptoms is all that it takes to treat, while others believe that as IBS is not life threatening, hence, there is no need of serious treatments. From the patients’ point of view, symptoms hamper their quality of life and therapy most often doesn’t help completely control their symptoms. So, they end up hopping from one medical facility to another.
How is IBS treated?
The first step in treating IBS is always patient education. Tests are done to rule out other diseases. Advice is given on lifestyle changes, to avoid symptoms and also diet. Drugs are used to control the symptoms. There is no curative therapy currently. Psychotherapy is often needed for treatment of severe and refractory symptoms.
Therapy is person-centric and requires an optimal physician-patient relationship. The lifestyle modifications advised are regular exercise, yoga, meditation, counselling and support, adequate sleep, etc. The dietary modification has a role. It is reasonable to avoid food that triggers symptoms like excess fats, high FODMAPS diet, excess caffeine or carbonated drinks, etc. Major exclusion diets are not routinely recommended. Inadequate fibre in the diet may contribute to IBS-C constipation. The drug therapies include laxatives for constipation, anti-diarrhoeal, pro antibiotics and antispasmodics, probiotics, antidepressants, etc. The different modes of psychotherapy are hypnotherapy, cognitive behavioural therapy, biofeedback therapy, etc. In most cases, IBS patients end up receiving a combination of drugs.