Irritable Bowel Syndrome Flashcards
What is irritable bowel syndrome (IBS) and what are the symptoms?
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
IBS is more common in?
Peaks in 30-40 year old people and is more common in females then males (2:1)
Pathophysiology of IBS?
Genes + environmental factors
There is disturbed GI motility with high-amplitude propagating contractions; there is an exaggerated gastro-colic reflex and pain
Cause of IBS?
Visceral hypersensitivty
Mechanisms of visceral hypersensitivity development?
Peripheral sensitisation due to inflammatory mediators causing up-regulation of the sensitivity of nociceptor terminals
Central sensitisation due to increased sensitivity of spinal neurones
Evidence and signs of peripheral and central hypersensitivity?
Peripheral - there is up to 20% recall onset after infectious gastroenteritis
Central hypersensitivity - increased pain radiation to somatic structures, e.g: fibromyalgia
How is a diagnosis of IBS decided?
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
Additional symptoms of IBS?
Bloating Urgency Sensation of incomplete emptying Mucous per rectum Nocturia (and poor sleep) Aggravated by stress
What other diseases is IBS assoc. with?
Fibromyalgia
Chronic fatigue syndrome
TMJ dysfunction
Chronic pelvic pain
Overlap is likely to occur in more severe IBS, assoc. with psychiatric problems
Psychological features of IBS?
Depression
Anxiety
Hypochondria
These all aggravate IBS
Concept of IBS?
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
What to include in an IBS history?
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
Alarm features in IBS?
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
Investigations for IBS?
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
Treatment of IBS?
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
Guidelines for managements of weak/inconclusive IBS?
Review fibre intake and adjust (usually a reduction is required), while monitoring symptoms
If fibre is needed, suggest oats
Dietary advice for IBS?
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
Why must opiates be stopped?
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
Why are anti-spasmodics used?
The studies are low quality and they do not constitute any benefit for diarrhoea/constipation but there is a global benefit and pain relief
Why are laxatives used?
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
Why are are anti-diarrhoeals used?
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
Why are anti-depressants used?
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
When are psychological therapies used?
If severe anxiety / depression
If no response to empiric anti-depressants
Options for psychological therapy?
Relaxation therapy
Cognitive Behavioural Therapy
Hypnosis
(moderate efficacy)
Simple management plan for IBS?
Diet changes
For symptom relief:
Loperamide/Movicol (laxatives)
Anti-spasmodics
Amitriptyline
