1. Irritable Bowel Syndrome
Dr Max Groome
Consultant Gastroenterologist
Ninewells Hospital, Dundee

2. Irritable Bowel: Outline
What is the best way to identify IBS patients?
What are the minimum number of relevant Ix?
What is the best management?

3. IBS: Background Chronic, relapsing problem Abdo pain Bloating
Change in bowel habit
10-20% population
Peaks in 30’s – 40’s
Females >males (2:1)

4. Pathophysiology of IBS
Genes + Environment
Disturbed GI motility; high-amplitude propagating contractions - exaggerated gastro-colic reflex, pain
Visceral hypersensitivity

5. Visceral pain sensation

6. Descending inhibitory pathways

7. Visceral hypersensitivity
Seen in 2/3 patients (gut distension studies)
Mechanisms
Peripheral sensitisation:
Inflammatory mediators up-regulate sensitivity of nociceptor terminals
Central sensitisation:
Increased sensitivity of spinal neurones

8. Evidence of hypersensitivity?
Peripheral:
Up to 20% recall onset after infectious gastroenteritis
Central:
Increased pain radiation to somatic structures eg fibromyalgia

9. Rome III criteria
Recurrent abdo pain/discomfort for at least 3 days per month for 3 months
+ 2 or more of:
Improvement with defecation
Onset assoc. with ∆ stool frequency
Onset assoc. with ∆ stool form (appearance)

10. Additional clues... Bloating Urgency Sensation of incomplete emptying
Mucus per rectum
Nocturia (and poor sleep)
Aggravated by stress

11. Association with other illnesses
Fibromyalgia
Chronic fatigue syndrome
Temporomandibular joint dysfunction
Chronic pelvic pain
Overlap cases likely to have more severe IBS, psychiatric problems

12. Psychological features
At least 50% are depressed/anxious/hypochondriacal
In tertiary centres, 2/3 have depression/anxiety

13. Irritable Bowel Concept

14. What is best way to identify IBS patients?

15. History A good history will make the diagnosis: Bowel habit
Bloating, nocturia
Diet (bread, fibre, meal times, bizarre exclusions)
Trigger factors (infection, menstruation, drugs)
Opiate use (codeine and Opiate/Narcotic bowel syndrome)
Psychosocial factors (stress)
Underlying fears (‘cancer’)

16. Alarm features Age > 50 Short duration of symptoms
Woken from sleep by altered bowel habit
Rectal bleeding
Weight loss
Anaemia
FH of colorectal cancer
Recent antibiotics

17. What are the minimum number of relevent investigations?

18. Investigations FBC ESR / plasma viscosity CRP
Antibody testing for coeliac disease (TTG)
Lower GI tests if aged >50 or strong FH of CRC

19. What is the best management plan?

20. Treatment of IBS Diet Regular meal times Reduce fibre Drugs:
Stop opiate analgesia
anti-diarrhoeals
Anti-spasmodics
Anti-depressants

21. Fibre and IBS NICE guidance 2008:
Evidence for ‘weak’ , ‘inconclusive’, ‘may be detrimental’
Suggest:
‘review fibre intake, adjusting (usually reducing) while monitoring symptoms. If fibre is necessary – suggest oats’

22. Stop opiates
With prolonged use can lead to ‘opiate/narcotic bowel syndrome’:
Worsening pain control despite escalating dose
Reliance on opiates
Progression of frequency, duration and intensity of pain
No GI explanation for pain

23. Anti-spasmodics (Mebeverine, Hyoscine)
Poor quality studies
Metanalysis:*
Global benefit vs placebo (NNT 5.5)
Relief of pain vs placebo (NNT 8.8)
No benefit for diarrhoea / constipation
*Poynard T Alimentary Pharm & Ther 2001

24. Laxatives Fibre aggravates pain
Stimulant laxatives eg Senna not a long-term solution (tachyphylaxis)
Lactulose promotes flatulence
PEG-based laxatives > lactulose*
*Attar A Gut 1999

25. Anti-diarrhoeals Loperamide (tablets or syrup) Opiate analogue
inhibits peristalsis, gut secretions
Benefits diarrhoea. No effect on pain.
No dependency
Use PRN / prophylactic
Cann P 1984 Dig Dis Sci.

26. Anti-depressants Tricyclics eg Amitriptyline Reduce diarrhoea
Reduce afferent signals from gut (‘central analgesics’)
Helps restore sleep pattern
Fits with ‘neuroplasticity’ theories:
Loss of cortical neurones in psychiatric trauma
Brain-derived neurotrophic factor increases with Rx (pre-cursor of neurogenesis)
Low dose 10 – night (NNT 5.2)*
Side effects limit use (NNH 22)
*Drossman DA 2003 Gastroenterology

27. Psychological treatment
If severe anxiety / depression
If no response to empiric anti-depressants
Options:
Relaxation therapy
Cognitive Behavioural therapy
Hypnosis
(moderate efficacy)

28. Irritable Bowel: Conclusions
What is the best way to identify IBS patients?
What are the minimum number of relevant Ix?
What is the best management?

29. What does the patient want?
Support and understanding
Clear explanation that IBS is an illness
Symptoms can be controlled by the patient
There is no miracle cure
There will be good days and bad
Explanation of treatment options
BSG IBS Guidelines 2007

30. Loperamide / movicol / anti-spasmodic
Summary of management
Careful history
Positive diagnosis of IBS
Simple management plan:
Diet
Symptom relief:
Loperamide / movicol / anti-spasmodic
Amitriptyline

31. Further reading BSG IBS Guidelines 2007 NICE IBS Guidance 2008
AGA technical review 2002