WHAT IS IRRITABLE BOWEL SYNDROME?

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by chronic, relapsing abdominal pain or discomfort, bloating, and changes in bowel habits.

WHAT IS THE PATHOPHYSIOLOGY OF IBS?

Symptoms of IBS

Following mechanisms are proposed in the causation of IBS: 

  • Gastrointestinal motor abnormalities (abnormal intestinal contractions, such as spasms and intestinal paralysis).
  • Excess bile acid synthesis or bile acid malabsorption has been identified as one cause of diarrhea-predominant IBS.
  • Abnormal psychological features (in up to 80% of IBS patients).
  • Prior sexual or physical abuse has been associated with IBS.
  • Gastroenteritis ('stomach flu or 'stomach bug'), a viral or bacterial infection of the stomach and intestines.
  • Immune activation and mucosal inflammation.

WHAT ARE THE CLINICAL FEATURES OF IBS?

The diagnosis of IBS relies on the recognition of positive clinical features and the elimination of other organic diseases. 

  • The peak prevalence of IBS is between 20 and 40 years of age. 
  • There is a significant female predominance and women make 80% of the population with severe IBS. 
  • Female patients with IBS commonly experience worsening of symptoms during the premenstrual and menstrual phases. 
  • IBS is diagnosed using clinical criteria that require the occurrence of abdominal pain or discomfort at least 3 days per month.
  • Other symptoms that can be present include defecation straining, urgency, or a feeling of incomplete bowel movement, passing mucus, and bloating. 
  • The stool is of small-volume without any evidence of blood. 
  • Abdominal pain in IBS is often exacerbated by eating or emotional stress and improved by the passage of stools. 
  • IBS symptoms tend to come and go over time and often overlap with other functional disorders such as fibromyalgia, headache, backache, and genitourinary symptoms.

WHAT ARE THE INVESTIGATIONS REQUIRED IN IBS?

If you are young with only mild symptoms, then only a minimal diagnostic evaluation is required. While an older person or an individual with rapidly progressive symptoms should undergo a more thorough examination.

  • A CBC (complete blood count) and sigmoidoscopic examination is required in most cases. 
  • Also, stool specimens should be examined for ova and parasites if you have diarrhea. 
  • In patients with persistent diarrhea not responding to simple antidiarrheal agents, a sigmoid colon biopsy is required to rule out microscopic colitis. 
  • If the main symptoms are diarrhea and increased gas, the possibility of lactase deficiency should be ruled out with a hydrogen breath test or with an evaluation after a 3-week lactose-free diet. 
  • Some patients with IBS-D (Irritable Bowel Syndrome with Diarrhea) may have undiagnosed celiac sprue. 

Following laboratory features argue against the diagnosis of IBS and necessitate other diagnostic considerations.

  1. Evidence of anemia
  2. Elevated ESR (Erythrocyte Sedimentation Rate)
  3. Presence of WBCs or blood in the stool
  4. Stool volume >200–300 mL/d

Blood tests for anti-CdtB and anti-vinculin antibodies may help distinguish between irritable bowel syndrome and inflammatory bowel disease. These antibodies develop in some patients after an acute bout of gastroenteritis. 

WHAT IS THE TREATMENT OF IBS?

  • You should recognize obvious food precipitants such as coffee, legumes, and cabbage and avoid them if they aggravate symptoms. 
  • The FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) diet plan is helpful in IBS. FODMAP are some carbohydrates and sugar alcohols that do not get absorbed in the body, resulting in abdominal pain and bloating.

  • Common food sources of FODMAPs are:
    • Fruits like apple, cherry, mango, pear, watermelon, peach, and plum. 
    • Vegetables like asparagus, beetroot, peas, mushrooms, chicory, and cauliflower.  
    • Cereals like wheat, rye, and barley; and legumes. 
    • Milk and milk products like yogurt and ice cream. 
    • Food additives like inulin, mannitol, sorbitol, and xylitol.
  • High-fiber diets and bulking agents, such as bran or hydrophilic colloid, are frequently used in treating IBS. Fiber like Psyllium husk should be started at a nominal dose and slowly titrated up as tolerated over several weeks to a targeted dose of 20–30 g of total dietary and supplementary fiber per day. 
  • When diarrhea is severe, especially in the painless diarrhea variant of IBS, a small dose of loperamide is the initial treatment of choice. 
  • Cholestyramine is another useful antidiarrheal agent. 
  • Eating slowly and avoiding chewing gum or drinking carbonated beverages may help in reducing bloating. 
  • Antibiotic treatment benefits a subset of IBS patients by modulating gut flora. 
  • The use of probiotics also helps by naturally altering the gut microbiome. 

    • CONCLUSION

    If you are suffering from prolonged IBS, consult your general physician immediately to understand the causes and methods of treatment.

    Disclaimer: This article is written by the Practitioner for informational purposes only. Users must not view the content as medical advice in any way. Users are also required to ’NOT SELF MEDICATE’ and always consult a practicing specialist before taking any medicines or undergoing any treatment. Practo and the Practitioner will not be responsible for any act or omission by the User arising from the User’s interpretation of the content.