Irritable Bowel Syndrome

Dr Max GroomeConsultant Gastroenterologist

Ninewells Hospital, Dundee

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?

IBS: Background

• Chronic, relapsing problem

Abdo painBloating

Change in bowel habit• 10-20% population• Peaks in 30’s – 40’s• Females >males (2:1)

Pathophysiology of IBS

• Genes + Environment

• Disturbed GI motility; high-amplitude propagating contractions - exaggerated gastro-colic reflex, pain

• Visceral hypersensitivity

Visceral pain sensation

Descending inhibitory pathways

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

Evidence of hypersensitivity?

• Peripheral:Up to 20% recall onset after infectious

gastroenteritis

• Central:Increased pain radiation to somatic structures

eg fibromyalgia

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)

Additional clues...

• Bloating• Urgency• Sensation of incomplete emptying• Mucus per rectum• Nocturia (and poor sleep)• Aggravated by stress

Association with other illnesses

• Fibromyalgia• Chronic fatigue syndrome• Temporomandibular joint dysfunction• Chronic pelvic pain

Overlap cases likely to have more severe IBS, psychiatric problems

Psychological features

• At least 50% are depressed/anxious/hypochondriacal

• In tertiary centres, 2/3 have depression/anxiety

Irritable Bowel Concept

What is best way to identify IBS patients?

History

• A good history will make the diagnosis:Bowel habitBloating, nocturiaDiet (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’)

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

What are the minimum number of relevent investigations?

Investigations

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

What is the best management plan?

Treatment of IBS

• DietRegular meal times

Reduce fibre• Drugs:

Stop opiate analgesiaanti-diarrhoealsAnti-spasmodicsAnti-depressants

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’

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

Poor quality studiesMetanalysis:*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

Anti-spasmodics (Mebeverine, Hyoscine)

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

Anti-diarrhoeals

• Loperamide (tablets or syrup)Opiate analogueinhibits peristalsis, gut secretionsBenefits diarrhoea. No effect on pain.No dependencyUse PRN / prophylactic

Cann P 1984 Dig Dis Sci.

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 traumaBrain-derived neurotrophic factor increases with Rx (pre-cursor of

neurogenesis)• Low dose 10 – 75mg @ night (NNT 5.2)*Side effects limit use (NNH 22)

*Drossman DA 2003 Gastroenterology

Psychological treatment

• If severe anxiety / depression• If no response to empiric anti-depressantsOptions:Relaxation therapyCognitive Behavioural therapyHypnosis(moderate efficacy)

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?

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

Summary of management

• Careful history• Positive diagnosis of IBS• Simple management plan:

DietSymptom relief:

Loperamide / movicol / anti-spasmodicAmitriptyline

Further reading

• BSG IBS Guidelines 2007• NICE IBS Guidance 2008• AGA technical review 2002