Irritable Bowel Syndrome is one of the common functional bowel diseases that affect us. Intestinal diseases may be classified broadly into Organic and Functional, where Organic refers to structural intestinal disease as compared to Functional disease where an identifiable structural bowel problem like an ulcer or narrowing (stricture) or bulge (diverticula of the intestine) is absent. IBS is characterised by abdominal pain and altered bowel habits (constipation or diarrhoea).
People with IBS tend to have visceral hypersensitivity i.e., increased perception of pain on intestinal distension. Studies done on IBS patients have shown increased inflammatory/ immune cells in the intestines (on biopsy) such as lymphocytes, mast cells which secrete inflammatory cytokines, histamine, serotonin and other substances that stimulate the nerves inside the bowel wall (Myenteric plexus) and cause increased cellular permeability, pain and increased contractions of the intestinal muscle leading to diarrhoea. This could be the cause for the so called post infectious IBS that is associated with bacterial, viral, protozoal and helminthic infections. There is also a theory that composition of fecal microbiota could be associated with the development of IBS. Small intestinal bacterial overgrowth (SIBO) also has an association with IBS. Studies done have shown that people with IBS have abnormal breath tests indicating bacterial overgrowth and gets better with antibiotc treatment which can reduce the bacterial population. Food allergies, carbohydrate indigestion and gluten sensitivty are also attributed as causes for IBS. Genetic causes, psychological causes such as anxiety depression phobias and somatization have also been shown to be risk factors for IBS development.
IBS is usally suspected when symptoms of abdominal pain and altered bowel habits persist for more than 3 months. The following are typical features of IBS: The symptoms could be either intermittent or continuous.
1. Abdominal pain for atleast 1 day a week. It is usually lower abdominal.
2. Changes in stool frequency – Constipation or diarrhoea
3. Changes in stool form – lumpy hard, pellet like or tooth paste like or loose and watery!
4. Change in stool passage – urgency, need to strain or having a feeling of incomplete evacuation
5. Bloating of abdomen.
6. Association with depression, anxiety, chronic stress or somatization.
What features would suggest that IBS is UNLIKELY!
1. Alarm symptoms such as alternating constipation with diarrhoea, blood in stools, nocturnal diarrhoea, weight loss and fever might indicate a more sinister pathology such as cancer or Inflammatory Bowel disease.
2. An Acute onset might suggest an infective cause for the symptoms.
Such people with the above features and those with a family history of cancer, Inflammatory Bowel disease or Coeliac disease would need other investigations such as Colonoscopy and biopsy.
IBS is classified into 4 types. IBS with diarrhoea (bowel movement > 3 /day), IBS with constipation (bowel movement < 3/week) , IBS with both diarrhoea and constipation and IBS that is not subtyped.
A complete blood count, ESR, CRP, stool complete and occult blood test, Stool calprotectin and and a sigmoidoscopy and colonoscopy may be done (for those with alarm features only) are some of the tests that may need to be done for someone suspected to have IBS.
IBS is a chronic disorder and therefore education and reassurance go a long way in helping the patient cope with the disorder. IBS is prone to recur with periodic exacerbations and remissions. Moderate exercise is believed to be helpful. Avoidance of gas causing food may also help. A diet low in FODMAPS (fermentable oligo, di, mono sacharides and polyols may be helpful. Restriction for 2-4 weeks may improve symptoms. The FODMAPs include 6 food groups:
1. Fructose – corn syrup, apple, pear, watermelon and raisins.
2. Fructans – garlic, onions, leeks, asparagus and antichokes.
3. Wheat based foods – breads, pasta, cereals, cakes.
4. Sorbitol – stone fruits
5. Raffinose – legumes, lentils, brussel sprouts, soybean and cabbage.
Many pharmacologic agents (medicines) are being used to treat IBS.
Antispasmodics such as hyoscyamine, dicyclomine and mebeverine and Probiotics are used for abdominal pain.
Loperamide can be used for diarrhoea.
Polyethylene glycol 3350 is used for constipation predominent IBS. Newer medicines such as Lubiprostone, Linaclotide, Plecanatide and Tegaserod are also used for the same condition. Antidepressants such as Tricyclics and SSRI are also useful. Rifaxamin, a non-absorbable antibiotic is used with good effect for bloating.
Cognitive behaviour therapy, yoga, relaxation and hypnotherapy is also believed to be helpful.