Irritable Bowel Syndrome Flashcards
What sort of disorder is IBS?
A functional disorder
List some factors which can trigger the onset of IBS.
Affective disorders e.g. depression and anxiety Psychological stress and trauma GI infection Antibiotic therapy Sexual, physical or verbal abuse Pelvic surgery Eating disorders
Does IBS affect more men or women? What is the ratio?
It affects more women in a ratio of 2:1.
What proportion of the population has IBS?
10 - 20 %
What factors can contribute to the pathophysiology of IBS?
Genes and the environment
Disturbed GI tract motility
Visceral hypersensitivity
What are the mechanisms of visceral hypersensitivity?
Peripheral sensitisation: Inflammatory mediators up-regulate sensitivity of nociceptor terminals
Central sensitisation: Increased sensitivity of spinal neurones
What is the evidence of hypersensitivity being a contributing factor to the pathophysiology of IBS?
Peripheral sensitisation: Up to 20% of IBS patients recall the onset of their symptoms after infectious gastroenteritis.
Central sensitisation: Some patients have increased pain radiation to somatic structures e.g. fibromyalgia.
What are the Rome III criteria for the diagnosis of IBS?
Recurrent abdominal pain/discomfort for at least 3 days of 3 preceding months plus 2 or more of the following:
- Improvement with defecation
- Onset associated with change in frequency of stool
- Onset associated with a change in form/appearance of stool
What are the subtypes of IBS patients?
IBS-C (with constipation) - hard or lumpy stools >25% and loose or watery stools 25% and hard or lumpy stools 25% and loose or watery stools >25% of bowel movements. Unsubtyped IBS (insufficient abnormality of stool consistency to meet criteria for IBS-C, D or M).
What are pointers to the need to investigate someone’s symptoms further?
The presence of symptoms identified in Rome III criteria in association with rectal bleeding, nocturnal pain, fever and weight loss and a clinical suspicion of organic diarrhoea.
What are additional symptoms to those listed in Rome III criteria that a patient may experience with IBS?
Bloating, urgency, sensation of incomplete emptying, mucus per rectum, nocturia (and poor sleep) and symptoms being aggravated by stress.
What are other illnesses associated with IBS?
Fibromyalgia Chronic fatigue syndrome Temperomandibular joint dysfunction Chronic pelvic pain Overlap cases are likely to have more severe IBS and psychiatric problems.
What percentage of IBS sufferers have psychological problems?
50% of IBS patients are depressed/anxious/hyperchonriacal.
In tertiary centres, 2/3 IBS patients have depression/anxiety
What are alarm features in a patient’s history?
Age > 50 Short duration of symptoms Woken from sleep by altered bowel habit Rectal bleeding Weight loss Anaemia FH of colorectal cancer Recent antibiotics
Should IBS cause rectal bleeding?
Why may patients with IBS have rectal bleeding?
No, it should not cause rectal bleeding, but many patients with IBS have haemorrhoids which could bleed.
What investigations should be done?
FBC, ESR/plasma viscosity, CRP, antibody testing for coeliac disease (TTG), Lower GI tests if >50 or the patient has a strong family history of colorectal cancer.
What is the treatment for IBS?
Dietary modification Laxatives Anti-motility agents Anti-spasmodics Anti-depressants Stop opiate analgesics Psychological therapy
What anti-diarrhoeal drug is used to treat IBS?
Loperamide (tablets or syrup)
This is an opiate analogue.
It inhibits peristalsis and gut secretions.
Benefits diarrhoea but has no effect on pain.
Use PRN or prophylactically.
What anti-spasmodics are used to treat IBS?
Mebeverine hydrochloride
Hyoscine
Dicycloverine hydrochloride
Peppermint oil
What laxatives can be used to treat IBS?
PEG-based laxatives are better than lactulose, which promotes flatulence. Patients should be advised against taking lactulose.
Stimulant laxatives such as Senna are not a long term solution as the patient develops tachyphylaxis to the drugs.
Name a 5HT4 receptor agonist that can be used to treat constipation.
prucalopride
Why should opiate analgesics be stopped in IBS?
Prolonged use of opiates can lead to opiate/narcotic bowel syndrome.
This is characterised by:
Worsening pain control despite escalating dose
Reliance on opiates
Progression of frequency, duration and intensity of pain
No GI explanation for pain
Why should increasing fibre intake not be used to treat constipation?
Fibre aggravates the pain.
What antidepressants can be used to treat IBS symptoms?
Firstly, tricycyclic antidepressants such as anitriptyline.
If these are not effective, selective serotonin reuptake inhibitors (SSRIs) should be considered.
How do tricyclic group anti-depressants such as amitriptyline help IBS symptoms?
Reduce diarrhoea
Reduce afferent signals from the gut (central analgesics)
Helps restore sleep pattern
Fits with “neuroplasticity” theories that there is a loss of cortical neurones in psychiatric trauma. A brain-derived neurotrophic factor which is a precursor of neurogenesis increases with treatment with the tricyclic group antidepressant.
When should psychological therapy be used?
What should this be?
Psychological therapy should be used if the patient has severe anxiety/depression or if there is no response to empiric anti-depressants.
Options for therapy could be relaxation therapy, cognitive behavioural therapy, or hypnosis.
If an increase in dietary fibre was advised, what type of fibre should this be?
Soluble fibre
When should treatment with tricyclic antidepressants be considered?
As second line treatment if laxative, loperamide or anti-spasmodics have not helped.
