Makindo Medical Notes

Related Subjects: |Ulcerative Colitis |Microscopic colitis |Irritable bowel syndrome |Lower Gastrointestinal (Rectal) Bleeding

Irritable Bowel Syndrome (IBS)

IBS is a chronic relapsing condition, often requiring empathetic and supportive care for effective management of symptoms. Though not life-threatening, IBS can significantly impact quality of life and functionality.

About

• IBS is a common functional gastrointestinal disorder that can cause a wide range of symptoms from mild discomfort to severe pain and bowel dysfunction.
• There is no cure, but expert and empathetic management can significantly reduce symptoms and improve quality of life.

Aetiology

• The frequency of IBS tends to decrease with age, though it persists in many patients.
• There are no demonstrable pathological findings associated with IBS, but studies suggest visceral hypersensitivity and dysregulation of the "brain-gut" axis.
• IBS is classified as a functional gastrointestinal disorder, where symptoms arise due to abnormal gut motility and sensitivity, often influenced by stress and emotional factors.
• IBS affects more women than men and is associated with higher rates of anxiety and depression, possibly contributing to symptom exacerbation.
• IBS incurs significant healthcare costs and is a leading cause of work absenteeism.

Clinical Presentation

• Symptoms typically last for at least 6 months.
• Abdominal pain: Variable in intensity, usually relieved by defecation.
• Change in bowel habits:
  • Diarrhoea-predominant IBS (IBS-D)
  • Constipation-predominant IBS (IBS-C)
  • Mixed-type IBS (IBS-M), with alternating diarrhoea and constipation.
• Other symptoms:
  • Feeling of incomplete evacuation
  • Mucus passage per rectum
  • Abdominal bloating, nausea, occasional vomiting
  • Extracolonic symptoms, such as heartburn and atypical chest pain, globus sensation (feeling of a lump in the throat)

Diagnostic Criteria (Rome IV Criteria)

• Recurrent abdominal pain, on average, at least 1 day per week in the last 3 months, associated with two or more of the following:
  • Related to defecation
  • Associated with a change in stool frequency
  • Associated with a change in stool form (appearance)
• Symptoms should be present for at least 6 months before diagnosis.

Supportive Symptoms for IBS Diagnosis

• Abnormal stool frequency (more than 3/day or less than 3/week).
• Abnormal stool form (e.g., lumpy/hard or loose/watery stools).
• Abnormal stool passage (e.g., straining, urgency, or sensation of incomplete evacuation).
• Mucus passage.
• Abdominal bloating or feeling of distension.

Red Flags: Consider Alternative Diagnoses

• Unintentional weight loss
• Anaemia
• Rectal bleeding
• Nocturnal gastrointestinal symptoms
• Family history of gastrointestinal cancers, inflammatory bowel disease, or coeliac disease
• Onset of symptoms after age 50

Investigations

• There are no specific biochemical or structural abnormalities associated with IBS; diagnosis is clinical and based on symptom criteria.
• Consider basic investigations to rule out other conditions:
  • Blood tests: FBC (to check for anaemia), ESR/CRP (to check for inflammation), thyroid function tests (TFTs), liver function tests (LFTs), urea and electrolytes (U&E).
  • Coeliac serology (e.g., anti-tTG or anti-endomysial antibodies) to rule out coeliac disease.
  • If there is a suspicion of colorectal disease: colonoscopy or sigmoidoscopy may be indicated, especially in cases with alarm symptoms.
  • If upper gastrointestinal disease is suspected: OGD (upper endoscopy) with duodenal biopsies.

Management

• Education and reassurance: Reassure the patient that IBS is a benign condition, though chronic and sometimes debilitating, and address any psychosocial factors that may exacerbate symptoms.
• Dietary modifications:
  • A high-fibre diet may be helpful, though fibre intake should be tailored according to symptom type (e.g., soluble fibre may benefit IBS-C).
  • Low FODMAP diet (low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) may help reduce symptoms of bloating and pain in some patients.
• Pharmacological treatment:
  • Antispasmodics (e.g., Mebeverine) can help relieve abdominal pain and cramping.
  • Antidiarrhoeals (e.g., Loperamide) for IBS-D, though they should be used cautiously to avoid constipation.
  • Laxatives (e.g., polyethylene glycol or lactulose) for IBS-C, but avoid stimulant laxatives as they can exacerbate symptoms over time.
  • Tricyclic antidepressants (TCAs) (e.g., Amitriptyline) for pain and diarrhoea-predominant IBS, with effects on gut motility and visceral sensitivity.
• Psychological therapies:
  • Cognitive Behavioural Therapy (CBT): Can help patients manage the anxiety and depression that often accompany IBS.
  • Biofeedback and relaxation techniques: Have shown some efficacy in managing symptoms in patients with stress-exacerbated IBS.