Irritable bowel syndrome

Irritable bowel syndrome

Ibs prevalence

Three main components of the IBS

Irritable Bowel Syndrome (IBS) is a common functional gastrointestinal disorder characterized by recurrent abdominal pain, discomfort, and altered bowel habits, such as constipation and diarrhea, without any detectable organic cause. As a gastroenterologist, it is essential to understand the pathophysiology, diagnosis, and treatment of IBS to provide appropriate care to affected patients.

Introduction

IBS affects up to 15% of the population and is more common in women than men. The condition can significantly impact patients' quality of life, leading to frequent healthcare visits and missed workdays. Although the exact cause of IBS remains unknown, it is thought to involve a complex interplay of genetic, environmental, and psychosocial factors.

Pathophysiology

The pathophysiology of IBS is not fully understood but is believed to involve multiple factors, including:

• Altered gut motility: Abnormal contractions of the smooth muscle in the intestinal wall can lead to either constipation or diarrhea in IBS patients.
• Visceral hypersensitivity: IBS patients often have increased sensitivity to pain and discomfort in the gastrointestinal tract, leading to exaggerated pain responses to normal physiological stimuli.
• Gut-brain axis dysfunction: The bidirectional communication between the gut and the brain may be disrupted in IBS, potentially contributing to both gastrointestinal and psychological symptoms.
• Low-grade inflammation: Some IBS patients may have mild inflammation in the intestinal lining, possibly contributing to the development of IBS symptoms.
• Microbiome alterations: Changes in the gut microbiota composition have been observed in IBS patients, although the significance of these changes is still under investigation.

Clinical Presentation

IBS is characterized by a combination of abdominal pain and altered bowel habits. The Rome IV criteria, which are used to diagnose IBS, require that patients have recurrent abdominal pain for at least one day per week over the past three months, associated with two or more of the following:

• Pain related to defecation
• A change in the frequency of stool
• A change in the form (appearance) of stool

IBS is further classified into subtypes based on the predominant bowel habit:

• IBS with constipation (IBS-C): Hard or lumpy stools at least 25% of the time and loose or watery stools less than 25% of the time.
• IBS with diarrhea (IBS-D): Loose or watery stools at least 25% of the time and hard or lumpy stools less than 25% of the time.
• IBS with mixed bowel habits (IBS-M): Hard or lumpy stools at least 25% of the time and loose or watery stools at least 25% of the time.
• IBS unclassified (IBS-U): Insufficient abnormality of stool consistency to meet criteria for the other subtypes.

Diagnosis

The diagnosis of IBS is primarily based on the patient's clinical history and the fulfillment of the Rome IV criteria. There is no specific diagnostic test for IBS; however, the following tests may be performed to rule out other possible causes of the patient's symptoms:

• Blood tests: Complete blood count, C-reactive protein, and erythrocyte sedimentation rate to check for inflammation or anemia, which may indicate other conditions such as inflammatory bowel disease or celiac disease.
• Stool tests: To check for infection, inflammation, or malabsorption, which may present with similar symptoms to IBS.
• Serologic tests: To screen for celiac disease in patients with diarrhea-predominant IBS or mixed bowel habits.
• Breath tests: To assess for small intestinal bacterial overgrowth (SIBO) or lactose intolerance, which can mimic IBS symptoms.
• Colonoscopy: In patients over 50 years of age or with alarm features (e.g., rectal bleeding, weight loss, anemia, or a family history of colorectal cancer or inflammatory bowel disease), a colonoscopy may be performed to rule out other conditions.

Treatment

There is no cure for IBS, but the following treatments may help manage symptoms:

• Dietary modifications: Patients may benefit from keeping a food diary to identify and eliminate trigger foods. A low-FODMAP (Fermentable Oligo-, Di-, Mono-saccharides, And Polyols) diet may be recommended for some patients to reduce symptoms.
• Fiber supplementation: Soluble fiber supplements (e.g., psyllium) may help improve constipation in IBS-C patients.
• Medications: Antispasmodics, laxatives, antidiarrheals, and medications targeting serotonin receptors may be prescribed depending on the patient's predominant symptoms.
• Probiotics: Some studies suggest that certain probiotic strains may be beneficial for IBS patients, but more research is needed to determine the most effective strains and doses.
• Stress management: Relaxation techniques, cognitive-behavioral therapy, and hypnotherapy may help improve IBS symptoms by addressing the gut-brain axis.
• Physical activity: Regular exercise may help alleviate symptoms by improving gut motility and reducing stress levels.

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