Bowels Behaving Badly

BAHSHE Conference

05-07-2005

Functional Bowel Disorders

• Classification and Diagnostic Criteria

• Epidemiology

• Pathophysiology

• Role of psychosocial factors.

• Diagnosis

• Treatment recommendations

• When or if to refer.

Definitions

• No objective biological markers exist.

• Spectrum of FGD defined by symptoms in the absence of structural pathology.

• Manning Criteria

• Rome I and II

Manning criteria

• Pain relieved by defaecation

• Looser stools with pain

• More frequent stools with pain

• Abdominal distension

• Passage of mucus

• Sensation of incomplete evacuation

Rome II criteria

• At least 12 weeks or more in preceding 12months of abdominal discomfort or pain with 2 of the following– Relieved by defaecation– Onset associated with change in frequency of

stool– Onset associated with change in consistency

of stool.

• Supportive features

Supportive features

• Altered stool frequency

• Altered stool form

• Altered stool passage (straining, urgency, incomplete evacuation)

• Passage of mucus

• Bloating

Prevalence of IBS as judged by Manning Criteria

No of symptoms

1 2 3 4 5 6

Male 27 10.7 5.0 2.3 1.3 0.9

Female 46.8 24 13.1 6 2.9 1.4

Epidemiology

• Prevalence – 14-24% women, 5-19% men

• Any age but decrease after 60

• 15% seek medical attention

• 25-50% of all referrals to gastroenterologists

• 2nd highest cause of work absenteeism

• Direct cost in USA $1.7billion in 2000

Social Impact

• Social activities restricted• Fear of travel• Work absenteeism (14.8 days per year v

8.7)• Anxiety• Extreme lethargy• In extreme virtually housebound.• Unnecessary surgery

Aetiology

• Gastrointestinal motility

• Visceral hypersensitivity

• Psychological discomfort

• Emotional distress

• Post-infectious

• Post-surgical

• Food intolerance

Gastrointestinal motility

• Basal motility is not consistently altered in IBS patients

• Gastro-colonic response in IBS results in increased duration of rectosigmoid contractions, compared with controls.

• Stress and anger increase colonic motility in IBS.

• In general motility studies are inconsistent and the normal range is wide.

Visceral Hypersensitivity

• Patients with bloating do not have increased quantities of gas in GI tract.

• Many have lowered tolerance of balloon distension in rectum (and elsewhere).

• Repetitive stimulation of the sigmoid can induce visceral hyperalgesia in IBS patient but not in controls.

• Stress and meals increase sigmoid contractions and hence may induce transient hyperalgesia in IBS.

Visceral Hypersensitivity

• BUT no increased visceral hypersensitivity is found in IBS “non-presenters”

• Visceral hypersensitivity is also found in patients with other chronic pain syndromes.

• Recent work involving functional MRI suggests that visceral hypersensitivity probably results from altered CNS processing of sensory information.

Psychosocial Factors

• IBS patients referred to hospital have an increased prevalence of anxiety, depression, phobias and somatisation.

• 25% think they have cancer.• Increased history of abuse in this group (20-

30%).• Non-presenters have same prevalence of these

as controls.• Psychological distress thus appears to influence

experience of IBS rather than cause it.

Stress

• Acute stress mimicked by CRF infusion– Increased colon motility– Decreased upper gut motility– Induces abdominal pain

• Chronic stress– >50% link onset to stressful life-event– In one study 60% of patients without chronic

stressor improved compared with 0% with .

Postinfectious

• IBS found in 20-30% after acute bacterial infection

• RR of IBS after proven infection =14 (nested case-control of 318 pts with bacterial gastroenteritis and 584,308 controls)

• Risk increased if long duration initial attack, female, younger age.

Possible mechanism

• Mucosal damage particularly with invasive organisms causing neural injury.

• Bile-salt malabsorption.

• Reduced disaccharidase activity.

• Altered bacterial flora

• Increased enteroendocrine cells.

• Unmasked IBD.

Postsurgical

• Hysterectomy, cholecystectomy, appendicectomy and any other abdomino-pelvic surgery may precipitate IBS.

• Prospective studies show about 10% develop new bowel symptoms within 6 months, usually constipation predominant IBS.

Mechanisms include

• Altered bowel flora after antibiotics,

• Neural damage with subsequent aberrant regeneration.

• Bile salt diarrhoea.

• Misdiagnosis of original problem.

Diet

• Intolerance– 30-60% have specific intolerance– Wheat, dairy, potato, corn, coffee, onions,

beef, oats, white wine

• Allergy– Much less common– Asthma, urticaria, angioedema– RAST or pinprick

Diagnosis in General Practice

• Careful detailed history over time• Examination including rectal examination

where relevant.• If typical features, <45y, no alarm

symptoms then make a positive diagnosis– Especially if female, frequent attender, long

history.

• If atypical or short history then screening investigations +/- referral.

When to refer

• Older patient presenting for first time.

• Atypical symptoms– Bleeding– Weight loss– Nocturnal symptoms– Anaemia

• Reassurance in patients with longstanding FGD but with new or worse symptoms.

Diagnosis in Hospital

• Cannot rely on symptom criteria alone

• History

• Examination

• Tests

History

• Onset• Alarm symptoms• Family history• Diet• Travel• Systemic symptoms• Drugs• Stool characteristics

Examination

• Disparity between well looking patient and desperate symptoms.

• Signs of systemic illness eg thyroid

• Abdominal mass

• Rectal examination, sphincter tone.

Investigations

• FBC, ESR, CRP

• TFTs

• Stool microbiology

• Sigmoidoscopy and biopsy

• Hydrogen breath test

Using these tests

• 1452 IBS patients in US study– 6% thyroid disease– 1% occult IBD– 20% lactose intolerance

• Other logical screening tests include– Anti-endomysial antibodies– Albumin– Calcium

Further tests

• Colonoscopy if>45y or FH

• Barium enema

• Barium follow through

• Ultrasound rarely helpful

Treatment of IBS

• General principles

• Therapeutic relationship

• Patient education

• Dietary modification

• Psychological approaches

• Simple drugs

• Complicated drugs

General Principles

• No known cure but “benign disease”

• Focus on symptom relief

• Alleviate concerns

• Simple explanation

• Consider hidden agenda

• Identify exacerbating factors

• Identify psychiatric comorbidity

Dietary Modification

• Fibre

• Lactose avoidance

• Avoidance of foods that increase flatulence– Beans, onions, carrots, sprouts, prunes etc

• Modified exclusion diet ( eg as per Hunter), >50% remission in 2 studies.

Modified Exclusion Diet

• Meat

• Fish

• Fruit (not citrus)

• Vegetables (not sweetcorn, onion, potato)

• Rice

Psychological Therapies

• Relaxation

• Biofeedback

• Hypnotherapy

• Cognitive Behavioural therapy.

• Psychiatry

Simple Drugs –symptom based

• Antispasmodics– Antimuscarinics- dicyclomine, hyoscine– Others- alverine, mebeverine, peppermint– Meta-analysis of 23 controlled trials found a

small but significant benefit (53 v 41%)– Mebeverine failed to show improvement in

pain but did result in global improvement.– Dicyclomine was best for pain.

Simple Drugs

• Loperamide

• Codeine

• Cholestyramine

• Laxatives

Antidepressants

• Several trials show benefit of low and high dose antidepressants.

• Tricyclics can normalise rapid transit times and modify visceral sensation.

• SSRIs can accelerate transit

New Drugs

• 5HT3 antagonists decrease diarrhoea

• 5HT4 antagonists decrease constipation

• Alosetron reduced diarrhoea in females with IBS.

• Tegaserod 5HT4 partial agonist, decrease colonic transit time.

Prognosis

• Incidence of new significant diagnosis is low– One study 0/104 at 5y– Another 3/112 at 5yrs (1 ca pancreas, 1

thyrotoxicosis, 1 gallstones)

• Symptoms persist in 30-95% in various studies.

Treatment Summary

• Positive Diagnosis

• Listen

• Explain and Reassure

• Dietary Advice

• Psychological considerations and treatment

• Pharmacological Treatment