Irritable Bowel Syndrome (IBS)

Overview

• IBS is a functional gastrointestinal disorder.
• Characterized by symptoms: abdominal pain, bloating, changes in bowel movements.
• Symptoms may persist for years, negatively impacting quality of life.

Associated Disorders

• Anxiety, major depression, chronic fatigue syndrome (ME/CFS) are common among IBS sufferers.

Other Names

• Spastic colon, nervous colon, mucous colitis, spastic bowel.

Medical Specialty

• Gastroenterology

Symptoms

• Diarrhea, constipation, abdominal pain.

Onset and Duration

• Usual onset before age 45.
• Long-term condition.

Causes and Risk Factors

• Causes: Unknown, but multiple factors proposed, include gut-brain axis issues, altered gut motility, visceral hypersensitivity, infections, neurotransmitters, genetic factors, food sensitivity.
• Triggers: Stressful life events, intestinal infection (post-infectious IBS).
• Risk Factors: Genetic predisposition, psychological stress, childhood abuse, food poisoning, psychiatric illness.

Diagnosis

• Based on symptoms and exclusion of other conditions.
• Requires ruling out other conditions like celiac disease, inflammatory bowel disease, colon cancer.
• Alarm features: onset after age 50, weight loss, blood in stool, family history of bowel disease.

Treatment

• Aim is to improve symptoms, no cure.
• Dietary Changes: Increase soluble fiber intake, low-FODMAP diet.
• Medications: Loperamide for diarrhea, laxatives for constipation, antidepressants.
• Other Treatments: Probiotics, counseling, good doctor-patient relationship.

Epidemiology

• Affects 10-15% in the developed world, 15-45% globally.
• More common in women in Western countries, not as pronounced in East Asia.
• Prevalence decreases with age.

Symptoms

• Primary: Abdominal pain or discomfort with diarrhea/constipation.
• Acute attacks that subside, recurrent.
• Additional: urgency, feeling of incomplete evacuation, bloating.
• Related to other symptoms: gastroesophageal reflux, genitourinary symptoms, fibromyalgia, headaches, psychiatric symptoms.

Specific Causes

• Allergy: Potential allergy-triggered immune mechanism.
• Stress: Braingut axis role, stress as a trigger.
• Gastroenteritis: Post-infectious IBS linked to gastroenteritis.
• Bacterial Overgrowth: SIBO more common in IBS sufferers.

Microbiota and IBS

• Alterations in gut microbiota associated with IBS symptoms.
• Certain bacteria are found in different abundances in IBS patients compared to healthy individuals.

Vitamin D

• Deficiency more common in IBS sufferers.

Genetic Links

• SCN5A mutations linked to IBS, especially constipation-predominant.

Mechanism

• Involves dysregulated brain-gut axis, serotonin metabolism, mucosal nerve fibers.

Diagnosis

• No specific tests; diagnosis based on symptoms, exclusion of other conditions.
• Rome criteria often used.

Differential Diagnosis

• Conditions with similar symptoms: colon cancer, inflammatory bowel disease, celiac disease.

Treatment Approaches

• Diet: Low-FODMAP for short-term relief, potential misdiagnosis risks.
• Fiber: Soluble fiber beneficial for IBS-C, not effective for IBS-D.
• Physical Activity: Recommended for symptom management.
• Medications: Antispasmodics, laxatives, antidepressants.
• Probiotics: May be beneficial, specific strains required.
• Herbal Remedies: Peppermint oil useful for short-term relief.
• Psychological Therapies: May help reduce symptoms.

Comorbidities

• Associated with neurological/psychiatric conditions, channelopathy, muscular dystrophy.
• Marginal association with inflammatory bowel disease.
• Increased risk of unnecessary surgeries.

Economic Impact

• Significant costs in healthcare and productivity loss associated with IBS.

Research

• Ongoing studies on gut microbiota, vitamin D supplementation, and mesalazine.

Conclusion

• IBS is a common, long-term disorder with significant impacts on life quality.
• Management focuses on symptom relief and improving quality of life.