301 IBS Flashcards
Does IBS pose threat to physical health?
No, does not increase chances of developing cancer or other bowel-related conditions
What can IBS follow?
Bout of gastroenteritis
IBS symptoms
Abdominal pain & cramping, change in bowel habits (diarrhoea), bloating & stomach swelling, flatulence, urgency to move bowels
Less common IBS symptoms
Lethargy, feeling sick, heartburn
When should you see a GP with suspected IBS?
Have IBS symptoms so can identify cause
Feeling anxious/change in mood as symptoms can worsen with stress
When should you urgently see a GP with suspected IBS?
Change in bowel habits >6 weeks especially 50+
Unexplained weight loss
Swelling/lump in stomach/back passage
Bleeding from back passage
Tell GP if Hx of bowel or ovarian cancer
Diagnosing IBS
No diagnosis but rule out coeliac or IBD
Blood tests and stool tests
Clinical features of IBS
Change in stool form/frequency
Leads to defaecation and associated bloating
What is IBS?
Abnormal smooth muscle activity
+/- visceral hypersensitivity
Abnormal central processing of painful stimuli
Possible mechanisms of IBS
- Visceral hypersensitivity
- Abnormal GI immune function
- Changes in colonic microbiota
- Abnormal central pain processing of afferent gut signals (altered brain-gut interactions)
- Abnormal GI motility
What is visceral hypersensitivity partially caused by?
Failed antinociceptive pathways
What happens after infectious gastroenteritis?
Raised serotonin-containing enteroendocrine cell concs. develop
Aetiology of IBS
Disordered bowel motility
Diet
Lifestyle
Psychological stress
GI contributing factors to IBS
Food intolerance
Lactose intolerance
Infection
Genetic factors
Possible risk factors of IBS
Genetic
Enteric infections (following gastroenteritis)
Dietary factors
Drugs (Abx)
Psychosocial (stress, anxiety or depression)
Why are psychosocial factors a risk factor for IBS?
Influence physiological function of GI via brain-gut axis, may affect person’s pain, symptoms, treatment and clinical outcome
Diagnosis of IBS
Abdominal pain/defecation relief/altered bowel movements/stool form
+2:
Altered stool passage, bloating, worse eating, passing mucus
(lethargy, nausea, upper GI)
IBS triggers
GI infection, Abx, pelvic surgery, psychological stress/trauma, sexual, physical, verbal abuse, mood disturbances, anxiety, depression, eating disorders, food intolerance
Alarm indicators for other diseases in IBS
Age >50 years
Male
Short history of symptoms (<6 months)
Documented weight loss
Nocturnal symptoms
Family Hx of colon cancer
Rectal bleeding
Recent Abx use
Exclude other diagnoses from IBS
Full blood count - anaemia, raised Plt count
ESR (erythrocyte sedimentation rate)
CRP (C-reactive protein)
Antibody test for coeliac antibodies (EMA) or (TTG)
ROME process
International effort to create scientific data to help diagnosis & treat functional GI disorders (IBS, functional dyspepsia & rumination syndrome)
Sub-types of IBS
- Diarrhoea predominant (IBS-D) - commonest
- Constipation predominant (IBS-C)
- Mixed, fluctuating between diarrhoea and constipation (IBS-M)
- Unclassified (IBS-U)
Lifestyle advice for IBS
Relaxation & increase physical activity
Restrict tea/coffee/alcohol/fizzy drinks but >8 cups of water or similar a day
Discourage aloe vera use
Advise weight loss
Avoid insoluble fibre (bran, corn or wheat) but if increased fibre needed then soluble (nuts, oats, ispaghula) - oats useful if wind & bloat is an issue
Probiotics >4 weeks
FODMAPS
What is a low FODMAP diet?
Fermentable
Oligosaccharides
Disaccharides
Monosaccharides
And
Polyols
(Short chained carbs (sugars) that small intestine absorbs poorly, very restrictive & only with dietician support)
Non-GI features of IBS: gynaecological
Painful periods (dysmenorrhoea)
Painful sexual intercourse (dyspareunia)
Premenstrual tension
Non-GI features of IBS: urinary
Frequency
Urgency
Nocturia
Incomplete emptying of bladder
Non-GI features of IBS: other
Back pain
Headache
Bad breath - unpleasant taste in mouth
Poor sleep
Fatigue
Medication options for IBS
If abdominal pain with spasms, consider antispasmodics (mebeverine, alverine, peppermint oil)
Constipation bulk forming laxatives such as ispaghula, if not tolerated, consider additional laxative like macrogol
Diarrhoea consider loperamide first line
Why do we not use lactulose in constipation?
Osmotic so makes it worse
Examples of bulk forming treatments in IBS
Ispaghula husk, methylcellulose, sterculia, Bran)
When are bulk forming treatments most appropriate in IBS
Most appropriate where dietary fibre cannot be increased & the patient has hard stools, haemorrhoids, anal fissures
Onset, side effects and contraindications of bulk forming treatments
12-36 hrs
Flatulence & distention
Colonic atony, obstruction, impaction
What is loperamide?
Synthetic opioid analogue
Opioid-receptor and acts on μ-opioid receptors in the myenteric plexus of large intestine
Properties of loperamide
High affinity for opiate receptors in gut
Extensive first pass metabolism (very little reaches systemic circulation)
Unlikely to cause opiate side effects (not cross BBB barrier - no addictive effects)
What medication to try for IBS if severely constipated for >12 months and all classes of laxatives?
Linaclotide (guanylate cyclase C agonist) which promotes secretion of intestinal fluid and speeds up bowel transit
Review after 12 weeks
TCAs (amitriptyline) at low doses for refractory abdominal pain
Review after 4 weeks and increase dose if needed
Consider SSRI is TCA not effective (off label use)
When to give prucalopride in IBS?
Tried 2 different types of laxatives at highest recommended doses, for 6 months & has not helped constipation and you & doctors are considering invasive treatment for constipation
What is prucalopride? Cause what? Costs how much?
5HT4 receptor agonist - cause nausea (10% patients) and prolong QT intervals, studies against placebo, cost £59.52 per month
What does prucalopride alter?
Colonic motility patterns via serotonin 5-HT4 receptor stimulation: stimulates proximal colonic motility, enhances gastroduodenal motility & accelerated delayed gastric emptying
