Irritable Bowel Syndrome
Also written as IBS.
Motility-related diarrhoea: abnormal intestinal transit time, e.g. irritable bowel syndrome, diabetic autonomic neuropathy.
Irritable Bowel Syndrome (IBS)
- Chronic and relapsing abdominal pain, bloating, changes in bowel habits (diarrhoea and/or constipation).
- Pathogenesis poorly defined: psychologic stressors, diet, abnormal GI motility.
- No gross or microscopic abnormalities in most patients — diagnosis based entirely on clinical symptoms .
- Manifests between 20–40 years ; significant female predominance .
- Prevalence in developed countries: 5–10% .
Read this in GASTROINTESTINAL PATHOLOGY (Part 3)
What our notes say
- Motility-related diarrhoea: abnormal intestinal transit time, e.g. irritable bowel syndrome, diabetic autonomic neuropathy. (Eoy paper 2 gen systemic Patho 2025 — Past Paper Questions & Answers)
- Example: irritable bowel syndrome, diabetic autonomic neuropathy, post-vagotomy/surgical states, hyperthyroidism. (General & Systemic Pathology SAQ Paper II — 15 July 2025 (MBPA 3500, MKU Year 3,)
- Symptom Relief in Functional Disorders: Placebos have shown effectiveness in relieving symptoms for conditions like irritable bowel syndrome and functional neurological disorders. (Human Communication Skills Exam Study Notes)
- Clinical Importance: Disrupted in diabetes, irritable bowel syndrome, and bacterial overgrowth (MBMP2300: Medical Physiology II MCQs)
- Irritable Bowel Syndrome (IBS): Dysregulation of enteric nervous reflexes and hormonal signals can result in altered secretion and motility. (Secretions of the Small Intestine and Their Control)
Study material on Irritable Bowel Syndrome
- GASTROINTESTINAL PATHOLOGY (Part 3)
- Paediatrics end of 2nd semester exam (MBPE 4300): 5 October 2021, 50 MCQs
- MCQ: GASTROINTESTINAL PATHOLOGY — 60 MCQs (Redistributed Answers)
Practice questions on Irritable Bowel Syndrome
A 35-year-old female with a history of Irritable Bowel Syndrome (IBS) develops sudden onset of severe LLQ pain with fever and leukocytosis. What is the most likely new diagnosis?
- Crohn's disease exacerbation
- Appendicitis
- Diverticulitis
- Ulcerative colitis flare
Answer: C. While IBS can cause LLQ pain, the acute onset of severe pain, fever, and leukocytosis suggests an inflammatory process like diverticulitis, which is more common in this age group and location than appendicitis (typically RLQ) or UC/Crohn's flares presenting with these acute symptoms. ---
A 20-year-old female with a history of irritable bowel syndrome (IBS) develops new onset of inflammatory bowel disease (IBD). Which symptom is most indicative of IBD over IBS?
- Abdominal pain relieved by defecation
- Bloating
- Rectal bleeding
- Intermittent constipation
Answer: C. Rectal bleeding is a hallmark symptom that differentiates inflammatory bowel disease (like ulcerative colitis) from irritable bowel syndrome, which typically does not involve bleeding. ---