11.2: Irritable Bowel Syndrome II: Clinical Features and Diagnostic Evaluation

Irritable Bowel Syndrome II: Clinical Features and Diagnostic Evaluation

Irritable Bowel Syndrome (IBS) is classified into subtypes based on the predominant bowel habits as determined by the Bristol Stool Form Scale (BSFS). The subtypes are:

1. IBS-C is primarily characterized by constipation. Individuals may experience infrequent bowel movements, difficulty passing stools, or a sensation of incomplete evacuation.
2. IBS-D, which involves recurrent episodes of diarrhea, is marked by an urgency to pass stools and frequent trips to the bathroom.
3. IBS-M, or mixed-type IBS, features a combination of both constipation and diarrhea with alternating bowel habits.
4. IBS-U (Unclassified) is for individuals whose symptoms do not conform to the above subtypes, including those with inconsistent or changing symptoms that do not follow a specific pattern.

Associated symptoms include abdominal distention, bloating, nausea, flatulence, an urgency to have a bowel movement, mucus in the stool, and a persistent sensation of incomplete evacuation. Notably, abdominal bloating often leads to visible distention. Besides gastrointestinal symptoms, non-gastrointestinal manifestations such as fatigue, headaches, and sleep disturbances may occur.

The diagnosis of IBS follows the Rome symptom-based criteria, which require the presence of abdominal pain or discomfort at least once a day over the last three months. The pain should be associated with two or more of the following:

1. Abdominal pain related to defecation
2. Abdominal pain accompanied by changes in stool frequency
3. Abdominal pain accompanied by changes in stool form or appearance

This systematic approach helps identify specific patterns of symptoms indicative of IBS.

To rule out other gastrointestinal conditions and confirm an IBS diagnosis, various diagnostic tests may be recommended, including:

1. Blood investigations to check for signs of inflammation or other underlying conditions.
2. Stool studies to analyze stool composition and rule out infections or malabsorption issues.
3. X-rays and abdominal scans to provide detailed images of the gastrointestinal tract and surrounding structures.
4. Colonoscopy, a medical procedure that involves inserting a camera-equipped flexible tube into the colon to visualize its internal structure and identify the root cause of symptoms.

The main clinical feature of irritable bowel syndrome, or IBS, is disrupted bowel patterns, categorized into subtypes based on predominant symptoms such as constipation, referred to as IBS-C, diarrhea classified as IBS-D, a combination of both called mixed type is indicated as IBS-M and IBS-U, categorized as unclassified for those not fitting into other categories.

Associated symptoms include lower abdominal distention, bloating, nausea, flatulence, urgency, mucus in the stool, discomfort often relieved by passing stools, and a sensation of incomplete evacuation.

Diagnosing IBS involves a comprehensive history collection, including symptoms, psychosocial factors, family history, and relevant drug and dietary patterns.

Additionally, a physical examination using the Rome IV criteria is required.

The criteria include abdominal pain at least once a week during the last three months, associated with two or more features, such as abdominal pain related to defecation, abdominal pain with altered stool frequency, and abdominal pain with altered stool appearance.

Additional diagnostic tests may include blood tests, stool studies, X-rays, abdominal scans, and endoscopic procedures like colonoscopy.

• Irritable Bowel Syndrome (IBS) - Characterized by varying bowel habits and varying gut symptoms.
• Bristol Stool Form Scale (BSFS) - A medical tool used to classify stool types.
• IBS-C - A subtype of IBS characterized by constipation predominant symptoms.
• IBS-D - A subtype of IBS marked by predominant diarrhea symptoms.
• IBS-M - Mixed-type IBS marked by alternating periods of constipation and diarrhea.

• Define IBS - Understand what it is and its varying forms (e.g., IBS-C, IBS-D).
• Contrast IBS-C vs IBS-D - Understand the key differences in symptoms and impact (e.g., constipation vs. diarrhea).
• Explore IBS Symptoms - Understand the associated symptoms and their impact (e.g., abdominal pain, bloating)
• Explain Diagnostic Process - Learn how IBS is diagnosed through a systematic process.
• Apply in Context - Understand diagnostic procedures and manifestations in real-life scenarios.

• What is IBS and how does society and lifestyle impact it?
• What are the key differences between IBS-C and IBS-D?
• How is IBS diagnosed and what does the diagnostic process entail?

• Students - Understand How IBS supports learning on human body and diseases.
• Educators - Provides a clear framework it helps with teaching human biology and pathologies.
• Researchers - Relevant for medical research and development of new treatments.
• Health Enthusiasts - Offer insights into human body and its disorders.