Irritable Bowel Syndrome

Question 1

What is irritable bowel syndrome (IBS) and what are the symptoms?

Answer 1

A chronic, relapsing problem involving:
Abdominal pain
Bloating
Change in bowel habit

There are sub-types but people can change over time:
IBS-D - diarrhoea predominance
IBS-C - constipation predominance
IBS-M - mixed

Question 2

IBS is more common in?

Answer 2

Peaks in 30-40 year old people and is more common in females then males (2:1)

Question 3

Pathophysiology of IBS?

Answer 3

Genes + environmental factors

There is disturbed GI motility with high-amplitude propagating contractions; there is an exaggerated gastro-colic reflex and pain

Question 4

Cause of IBS?

Answer 4

Visceral hypersensitivty

Question 5

Mechanisms of visceral hypersensitivity development?

Answer 5

Peripheral sensitisation due to inflammatory mediators causing up-regulation of the sensitivity of nociceptor terminals

Central sensitisation due to increased sensitivity of spinal neurones

Question 6

Evidence and signs of peripheral and central hypersensitivity?

Answer 6

Peripheral - there is up to 20% recall onset after infectious gastroenteritis

Central hypersensitivity - increased pain radiation to somatic structures, e.g: fibromyalgia

Question 7

How is a diagnosis of IBS decided?

Answer 7

Rome III criteria:
Recurrent abdominal pain/discomfort for at least 3 days per month for 3 months

+ 2 or more of:
Improvement with defecation
Onset assoc. with change in stool frequency
Onset assoc. with change in stool form/appearance

Symptoms should have lasted 6 months

Question 8

Additional symptoms of IBS?

Answer 8

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

Question 9

What other diseases is IBS assoc. with?

Answer 9

Fibromyalgia
Chronic fatigue syndrome
TMJ dysfunction
Chronic pelvic pain

Overlap is likely to occur in more severe IBS, assoc. with psychiatric problems

Question 10

Psychological features of IBS?

Answer 10

Depression
Anxiety
Hypochondria

These all aggravate IBS

Question 11

Concept of IBS?

Answer 11

An acute infection, along with the resulting mucosal inflammation, leads to visceral hypersensitivity and dysmotility

The mucosal inflammation causes psychological distress, which can aggravate the problem

All of these interacting factors combine to produce IBS symptoms

Question 12

What to include in an IBS history?

Answer 12

Bowel habits
Bloating and nocturia

Consider diet - fibre, meal times; patients may exclude certain foods

Consider trigger factors - infection, menstruation and drugs

Consider opiates, e.g: codeine - can worsen constipation and can lead to opiate/narcotic bowel syndrome (chronic or frequently recurring abdominal pain that worsens with continued/escalating narcotic doses)

Consider psychological factors, like stress, and underlying fears, like cancer

Question 13

Alarm features in IBS?

Answer 13

Age > 50
Family history of colorectal cancer

Short duration of symptoms
Woken from sleep by altered bowel habit
Rectal bleeding
Weight loss
Anaemia

Recent antibiotics

Question 14

Investigations for IBS?

Answer 14

There are no specific tests

Full blood count

Inflammatory markers (if raised, consider referral for IBD):
ESR/plasma viscosity
CRP

Antibody testing for coeliac disease, i.e: TTG

Lower GI tests if they are aged over 50 or if they have a family history of colorectal cancer

Question 15

Treatment of IBS?

Answer 15

Diet - regular meal times and reduction of fibre

Drugs - stop opiate analgesia and use:
Anti-diarrhoeals
Anti-spasmodics - reduce pain and spasm in IBS
Anti-depressants
Many patients respond to placebo in studies

Question 16

Guidelines for managements of weak/inconclusive IBS?

Answer 16

Review fibre intake and adjust (usually a reduction is required), while monitoring symptoms

If fibre is needed, suggest oats

Question 17

Dietary advice for IBS?

Answer 17

Restrict tea and coffee intake; caffeine aggravates IBS
Reduce intake of ‘resistant starch’

People with diarrhoea should avoid sorbitol (artificial sweetener that has a laxative effect)

If IBS symptoms persist, onsider single food avoidance and exclusion diets, i.e. low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides And Polyols) diet; this is very restrictive and requires a dietician, as there is a risk of malnutrition

Question 18

Why must opiates be stopped?

Answer 18

With prolonged use can lead to opiate/narcotic bowel syndrome where there is no GI explanation of pain and the following symptoms:
Worsening pain control despite escalating dose
Reliance on opiates
Progression of frequency, duration and intensity of pain

Question 19

Why are anti-spasmodics used?

Answer 19

The studies are low quality and they do not constitute any benefit for diarrhoea/constipation but there is a global benefit and pain relief

Question 20

Why are laxatives used?

Answer 20

Fibre aggravates pain in IBS so stimulant laxatives are used but, e.g: Senna is not a long-term solution

Lactulose promotes flatulence and bloating so PEG-based laxatives are better

Question 21

Why are are anti-diarrhoeals used?

Answer 21

E.g: Loperamide is an opiate analogue that entails no dependency

It inhibits peristalsis and gut secretions do there are benefits for diarrhoea but there is no reduction of pain; it is used prophylactically, e.g: before an event to prevent diarrhoea

Question 22

Why are anti-depressants used?

Answer 22

Tricyclics, e.g: Amitriptyline:
Reduce diarrhoea
Reduce afferent signals from gut (central analgesics)
Help restore sleep pattern
Increase neuroplasticity 

There is a loss of cortical neurones in psychiatric trauma; brain-derived neutrotrophic factor increases with this drug, which is a pre-cursor of neurogenesis

Low dose is used (10-75 mg at night) but side effects, like dry mouth and fatigue, limit use

Question 23

When are psychological therapies used?

Answer 23

If severe anxiety / depression

If no response to empiric anti-depressants

Question 24

Options for psychological therapy?

Answer 24

Relaxation therapy
Cognitive Behavioural Therapy
Hypnosis
(moderate efficacy)

Question 25

Simple management plan for IBS?

Answer 25

Diet changes

For symptom relief:
Loperamide/Movicol (laxatives)
Anti-spasmodics
Amitriptyline