Irritable bowel syndrome

Question 1

What is irritable bowel syndrome?

Answer 1

Irritable bowel syndrome (IBS) is a chronic condition characterised by abdominal pain associated with bowel dysfunction, without any identifiable structural or biochemical abnormalities.

Question 2

Summarise the epidemiology of IBS

Answer 2

• COMMON
• 10-20% of adults
• More common in females (2:1 ratio)
• F>M (2:1), highest prevalence in people aged 20-39 (onset of symptoms after age of 50 is unusual)

Question 3

What are the risk factors for IBS?

Answer 3

female, age <50, previous enteric infection, history of physical or sexual abuse, family history, stress

Question 4

What causes IBS?

Answer 4

UNKNOWN
- Could be visceral sensory abnormalities (having an abnormally strong response to stretch of the gut), gut motility abnormalities (short chain carbs that are consumed start to draw out water -> diarrhea), psychosocial factors (e.g. stress), food intolerance (e.g. lactose) and many more
IBS is usually a diagnosis of exclusion

Question 5

What are the presenting symptoms of IBS?

Answer 5

1. 6+ months history of abdominal pain
   - Pain is often colicky
   - It is in the lower abdomen
   - Relieved by defecation or passing of flatus
2. Altered bowel frequency (> 3 motions per day or < 3 motions per week)
3. Abdominal bloating/distension
4. Change in stool consistency
5. Worsening of symptoms after food
6. Passage with urgency or straining
7. Tenesmus
8. Other symptoms: nausea, bladder symptoms, back ache
9. Symptoms are CHRONIC and exacerbated by stress, menstruation or gastroenteritis (post-infection IBS)
10. MAKE SURE YOU SCREEN FOR RED FLAG SYMPTOMS:
    - History < 6 months
    - Weight loss
    - Anaemia
    - PR bleeding
    - Late onset (> 60 yrs)
    - NOTE: if any of these are present then you must exclude colonic malignancy

Question 6

What signs of IBS can be found on physical examination

Answer 6

• Usually NORMAL on examination
• Sometimes the abdomen may appear distended and be mildly tender on palpation in one or both iliac fossae

Question 7

What investigations are used to diagnose/ monitor IBS?

Answer 7

1. Diagnosis is mainly from the history but organic pathology must be excluded
2. Blood: FBC (anaemia), LFT, ESR, CRP, TFT, anti-endomysial/anti-tranglutaminase antibodies (if negtaive, coeliac disease is ruled out & IBS more likely)
3. Stool examination: microscopy and culture for infective cause
4. Faecal calprotectin (not raised in IBS, distunguishes b/t IBD where it is raised)
5. Ultrasound: exclude gallstone disease
6. Urease breath test: exclude dyspepsia due to Helicobacter pylori
7. Endoscopy: if other pathologies suspected

Question 8

How is IBS managed?

Answer 8

1. Advice: dietary modification – fibre, lactose, fructose, wheat, starch, caffeine, alcohol, fizzy drinks may worsen symptoms
2. For constipation: increase soluble fibre, bisacodyl and sodium picosulfate
3. Medical: depends on the main symptoms affecting the patient
   - Antispasmodics (e.g. buscopan) – for colic/bloating
   - Prokinetic agents (e.g. domperidone, metaclopramide)
   - Anti-diarrhoeals (e.g. loperamide) – for diarrhoea
   - Laxatives (e.g. senna, movicol, lactulose) – for constipation
   - Low-dose tricyclic antidepressants (may reduce visceral awareness) – for psychological symptoms/visceral hypersensitivity
4. Psychological therapy:
   - CBT
   - Relaxation and psychotherapy

Question 9

What complications may arise from IBS?

Answer 9

• Physical and psychological morbidity
• Increased incidence of colonic diverticulosis

Question 10

Describe the disease course of IBS

Answer 10

• Chronic relapsing and remitting course of disease
• Often exacerbated by psychosocial stresses

Question 11

What red flag symptoms should you screen for in a pt with suspected IBS?

Answer 11

SYMPTOMS:
- Weight loss
- Anaemia
- PR bleeding
- Late onset (> 60 yrs)
- NOTE: if any of these are present then you must exclude colonic malignancy