Irritable Bowel Syndrome
Dr Max Groome
Consultant 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 pain
Bloating
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...
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Bloating
Urgency
Sensation of incomplete emptying
Mucus per rectum
Nocturia (and poor sleep)
Aggravated by stress
Association with other illnesses
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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 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’)
Alarm features
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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
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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
• Diet
Regular meal times
Reduce fibre
• Drugs:
Stop opiate analgesia
anti-diarrhoeals
Anti-spasmodics
Anti-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
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
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 analogue
inhibits peristalsis, gut secretions
Benefits diarrhoea. No effect on pain.
No dependency
Use 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 trauma
Brain-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-depressants
Options:
Relaxation therapy
Cognitive Behavioural therapy
Hypnosis
(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?
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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:
Diet
Symptom relief:
Loperamide / movicol / anti-spasmodic
Amitriptyline
Further reading
• BSG IBS Guidelines 2007
• NICE IBS Guidance 2008
• AGA technical review 2002