Irritable Bowel Syndrome (IBS)

Gastroenterology (12%) Core Clinical Conditions

1A: Able to diagnose and manage

Jump to content

Definition Aetiology Pathophysiology Risk factor Sign and Symptoms Investigations Management

Irritable Bowel Syndrome (IBS) is a prevalent gastrointestinal illness characterised by a collection of persistent symptoms pertaining to the digestive system. The symptoms commonly observed in individuals with this condition include abdominal pain or discomfort, change in bowel habits (such as diarrhoea, constipation, or a combination of both), and bloating. Irritable bowel syndrome (IBS) is classified as a functional disorder, indicating the absence of structural abnormalities or observable indications of pathology inside the gastrointestinal tract.

• Altered Gut Motility: IBS is associated with abnormal contractions of the colon (large intestine) that can lead to diarrhoea or constipation.

• Visceral Hypersensitivity: Individuals with IBS may have heightened sensitivity to pain and discomfort in the digestive tract.

• Gut-Brain Interaction: Stress, anxiety, and other emotional factors can influence IBS symptoms through the gut-brain axis.

• Microbiome Imbalance: An imbalance in the gut microbiome may play a role in IBS.

The actual cause is unknown, possible causes include:

• Abnormal Gut Motility: for example, abnormal contractions might cause constipation, diarrhoea, or both.

• Hypersensitivity due to low grade inflamation, this inflammation may cause IBS hypersensitivity and altered motility.

• Change in Gut Microbiota: the Intestinal microbiota is a complex collection of bacteria. In IBS patients commonly have gut microbiota abnormalities, including changes in bacterial diversity and abundance.

• Psychological factors: Psychological factors including stress, anxiety, and sadness.

• Genetic and Epigenetic Factors: While unknown, genetic and epigenetic factors may cause IBS. Certain genetic variants enhance IBS risk, suggesting a hereditary component. Epigenetic changes, which affect gene expression without affecting DNA sequences, may also affect gut function and sensitivity in IBS.

1. Gender: Women are more likely to develop IBS compared to men.
2. Age: IBS can affect individuals of all ages, but it tends to be more common in younger individuals. The condition often manifests during late adolescence or early adulthood. However, IBS can also develop later in life, especially in individuals who have experienced significant stressful events.
3. Family History: There appears to be a genetic predisposition for developing IBS. If a close family member such as a parent or sibling has IBS, the risk of developing the condition may be higher.
4. Psychological Factors: Psychological distress and mental health conditions, such as anxiety, depression, and chronic stress, may contribute to the onset and exacerbation of symptoms in individuals with IBS. The gut-brain axis is thought to play a significant role, as emotional factors can impact the functioning of the gut.
5. Gastrointestinal Infections: A previous history of gastrointestinal infections, such as bacterial gastroenteritis, can increase the risk of developing IBS. These infections can trigger changes in the gut microbiota and increase intestinal sensitivity and permeability, leading to the development of IBS symptoms.
6. Abnormal Gut Motility: Some individuals with IBS have abnormalities in the way their intestines move and contract, resulting in either increased or decreased motility. These motor abnormalities can cause irregular bowel movements and flare-ups of IBS symptoms.
7. Food Intolerance: Certain food types, such as high-fat foods, spicy foods, alcohol, caffeine, and carbonated beverages, have been known to trigger IBS symptoms in susceptible individuals. Intolerances to specific foods or food groups, such as lactose or gluten, may also contribute to the development of IBS symptoms.
8. Stress and Trauma: Chronic or acute stress, as well as a history of physical, emotional, or sexual abuse, may increase the risk of developing IBS or exacerbating existing symptoms. Stressful life events, such as bereavement or job loss, can trigger the onset of IBS symptoms in susceptible individuals.
9. Hormonal Factors: Hormonal fluctuations, particularly in women during their menstrual cycles, may influence IBS symptoms.

1. Abdominal Pain and Cramping: One of the most common symptoms of IBS is recurring abdominal pain, which is often described as cramping or aching. The intensity and location of the pain can vary among individuals.
2. Bowel Habit Changes: IBS can cause changes in bowel movements. These changes can include diarrhoea, with loose and watery stools occurring more frequently, or constipation, where passing stools becomes difficult and less frequent. Some individuals may experience alternating bouts of both diarrhoea and constipation.
3. Altered Stool Consistency: People with IBS may notice changes in the consistency of their stools. This can range from loose and watery stools to hard and lumpy stools.
4. Bloating and Excessive Gas: Many individuals with IBS experience bloating, which is an uncomfortable feeling of fullness and tightness in the abdomen. This may be accompanied by increased gas production, leading to flatulence.
5. Mucus in Stools: In some cases of IBS, individuals may notice the presence of mucus in their stools. This can occur due to irritation and inflammation in the intestinal lining.
6. Feeling of Incomplete Evacuation: People with IBS often report a sensation of not fully emptying their bowels after a bowel movement. This can be frustrating and may lead to a constant urge to use the restroom.
7. Fatigue and Sleep Disturbances: Chronic IBS symptoms can affect sleep patterns, leading to reduced quality of sleep and resulting in fatigue and decreased energy levels.
8. Anxiety and Depression: IBS is closely associated with psychological factors such as anxiety and depression. The stress and discomfort caused by the condition can contribute to the development or exacerbation of these mental health conditions.

1. Medical History and Physical Examination: A healthcare professional will assess your symptoms, such as abdominal pain, bloating, diarrhoea, or constipation. They will also ask about the duration, frequency, and severity of these symptoms. A physical examination may be conducted to rule out other potential causes.
2. Stool Tests: In some cases, stool tests may be performed to rule out infection or other conditions that may present with similar symptoms. These tests can include analysis for faecal calprotectin, H. Pylori stool test, parasites, or FIT test.
3. Blood Tests: Blood tests may be conducted to assess for any underlying conditions that can cause similar symptoms, such as celiac disease, thyroid disorders, or inflammatory markers like C-reactive Protein (CRP) and erythrocyte sedimentation rate (ESR).
5. Colonoscopy or Flexible Sigmoidoscopy: These procedures involve examining the rectum and colon using a thin, flexible tube with a camera. Colonoscopy allows visualization of the entire colon, while sigmoidoscopy covers the lower part of the colon. These tests help rule out other conditions like inflammatory bowel disease (IBD), colorectal cancer, or polyps.
6. Lactose Intolerance Test: Lactose intolerance can sometimes mimic IBS symptoms. This test involves measuring blood glucose levels after consuming a lactose-containing drink to assess lactose digestion.

1. Education and Information: Healthcare professionals should provide education and information about IBS to patients, helping them understand the condition and its potential triggers. It is important to address any misconceptions and provide reassurance to alleviate anxiety.
2. Dietary and Lifestyle Advice: NICE emphasizes the importance of dietary changes and lifestyle modifications as the first step in managing IBS. This includes encouraging patients to maintain a healthy and balanced diet, avoiding trigger foods, and incorporating regular physical activity into their routine.
3. Fibre Supplementation: For patients experiencing constipation as a predominant symptom, NICE recommends considering a trial of soluble fibre. This may help improve bowel movements and relieve symptoms. The use of fibre should be tailored to each individual's needs and adjusted gradually.
4. Antispasmodic Medication: NICE suggests offering a low-dose antispasmodic medication as a short-term treatment option for patients with abdominal pain or cramps associated with IBS. This may help relax the muscles in the gut and reduce pain.
5. Psychological Therapies: Psychological therapies such as cognitive-behavioural therapy (CBT) and hypnotherapy have shown effectiveness in managing IBS symptoms. NICE recommends considering these therapies for patients with ongoing symptoms despite other interventions.
6. Pharmacological Treatments for diarrhoea or Constipation: In certain cases, when dietary and lifestyle changes alone are insufficient, NICE suggests considering pharmacological treatment options. For diarrhoea-predominant IBS, loperamide can be offered, while for constipation-predominant IBS, laxatives like macrogol or stimulants can be considered.
7. Referral for Specialist Advice: Referral to a specialist should be considered if there are severe symptoms, diagnostic uncertainty, or a lack of response to initial management strategies. Specialists can further investigate and provide expert guidance on treatment options.

Jump to other topics below: