Irritable Bowel Syndrome Flashcards
what is IBS
■ Functional gastrointestinal disorder. ■ Characterized by altered bowel habits and abdominal pain. ■ Most common GI disorder seen by primary care physicians. ■ Commonly underdiagnosed
Epidemiology
■ Prevalence – 10 - 25%
– 2- 3 times more common in women
– Onset often under the age of 40.
■ May have a genetic predisposition.
■ GI infection with subsequent inflammation may play a role
– prior acute bacterial gastroenteritis (6 x increased risk)
■ Close association with psychological/affective disorders
– anxiety, panic disorders, depression
■ Higher incidence of stressful life events (ie
physical/sexual abuse)
■ Overlap with fibromyalgia
– up to 60% of patients with fibromyalgia have IBS
■ Presence of IBD or colitis (2 – 3 fold increased risk of having IBS)
Pathophysiology
Brain-Gut Axis:
■Sensorimotor disturbances of small/large bowel.
■Associated with visceral hypersensitivity and lowered pain threshold.
■May involve the peripheral enteric nervous system (ENS) and the central nervous system (CNS).
May be related to downregulation of
serotonin (5-HT) receptor in the GI tract
Disturbances of SI and LI, sensory motor disturbances
Lowered pain threshold
Visceral hypersensitivity
Increased sensitivity of GI tract for things we normally find ok
Gas, food
Pathophysiology
Brain-Gut Axis:
5-HT3 vs 5-HT4
5-HT3 – regulates GI motility + transmission of pain
signals
5-HT4 – increases GI contractions
Down regulation of serotonin receptors
Psychosocial neuromodulation
vs Post-inflammatory neuromodulation
psychosocial: trauma, hx of depression affecting CNS
post-inflamm: ENS, GI infection affecting enteric NS
leads to enteric sensorimotor dysfunction
Filtering mechanism with gas
visceral hypersensitivity, noxious and physiological stimuli
GI microbiota theory
Small intestine bacterial overgrowth (SIBO)
– Common to see with IBS
– ?coincidental or a cause
Dont know if it’s coincidental or causing it
More bac in small intestine
Endoscopy required to catch it and truly diagnose it
Can do breath test
Symptoms of IBS
■ Abdominal pain - 2/3rd of patients
– usually crampy, achy
– relieved with defecation (80%)
– worsened by meals Within an hour or 2 after meals lots of ab pain
■ Bloating, gas
■ Changes in bowel habits
– diarrhea or constipation predominant, or alternating between diarrhea or constipation (called mixed)
Heartburn, often not recognized as much
■ Upper GI symptoms such as dyspepsia are common
Alarm symptoms
These symptoms need further investigation as they are not associated with IBS: ■ Blood in stools ■ Nocturnal symptoms ■ First incidence >50 years of age It may be IBS but should be checked ■ Fever – ongoing ■ Unexplained weight loss
Alterations in GI motility are also seen with:
■ psychologic factors:
– stress, anger
■ diet (can aggravate symptoms)
– alcohol, fatty food, caffeine, lactose, sorbitol, fructose
– lactose intolerance common
■ celiac – 5x higher with IBS
■ hormone fluctuations with menstrual cycle
– common with dysmenorrhea
Lot of cases lactose intolerant
Estrogen and prog receptors in Gi tract
worsening of symptoms during hormonal fluctuations before period
■ Other concurrent conditions
– Fibromyalgia
– Chronic fatigue syndrome
– Psychiatric
• Anxiety, depression
Diagnosis
what is Rome IV criteria
■ Diagnosis is made when symptoms have persisted
over a period of time.
■ Abdominal pain or discomfort that occurs in
association with altered bowel habits over a period of
at least 3 months
Recurrent abdominal pain at least 1 day per week
during the previous 3 months associated with 2 or
more of the following:
– Related to defecation (may be increased or unchanged with defecation
– Associated with a change in stool frequency
– Associated with a change in stool form or
appearance
Subtyping IBS by Predominant
Stool Pattern
4 classes
1) IBS-D – diarrhea predominant
loose or watery stools >25%and hard or lumpy stools <25%of BM
2) IBS-C – constipation predominant
hard or lumpy stools >25%and loose or watery stools <25%of BM
3) IBS-M – mixed diarrhea and constipaton
hard or lumpy stools >25%and loose or watery stools >25%of BM
4) IBS-U – unclassified
symptoms can not be classified into the one of the 3 subtypes
Cant tell which is more predominant
Treatment Goals
■ Relieve symptoms
■ Improve quality of life
■ Reduce missed days at work or school
Management of IBS
first step
there is no consistently successful therapeutic approach for patients – typically IBS is a chronic condition.
- education, psychologic therapies, exercise, diet, probiotics
identify predominant IBS symptom
Psychosocial Strategies
■ Types of psychological therapies: • hypnosis • biofeedback • relaxation techniques • meditation • mindfulness • cognitive-behavioral therapy ■ May be helpful in relieving anxiety and distress over symptoms • not clear if helpful for frequency of bowel symptoms ■ Exercise – can also be beneficial Cognitive behavioural therapy for IBS
Management of IBS: Diet
what type of diet
what foods to avoid
Diet modification alone will help mild to moderate
symptoms
– low fat diet
– adequate dietary fiber – wholegrain cereals, fruit,
veggies
• fiber enriched diet (mainly if constipation)
– avoid eating large meals (try smaller, more frequent
meals)
Elimination diets:
■ Avoid foods that worsen symptoms: dairy (ie lactose intolerance) caffeine, alcohol, sorbitol artificial sweeteners, MSG, reduce beans, lentils – poorly digestible, fermentable, carbohydrates
■ avoid things that increase flatulance – ie chewing
gum, carbonated beverages, drinking thru straw
what are FODMAPs
Fermentable
Oligo-DiMonoSaccharrides And Polyols
see table
Increased fermentation
Get broken down
Cause a lot of gas formation
need to have low FODMAP diet
Management of IBS: education
■ Education very important!
■ Validate symptoms, symptoms are real, not all in
your mind
■ Symptoms have a physiologic cause but poorly
understood.
■ They themselves can control symptom triggers.
– Identification and avoidance of triggers.
■ Daily symptom diaries may be helpful (and recording
triggers)
There are physiologic causes
Not all in the mind
Feels out of control control at that time
Probiotics in IBS
■ Several meta-analysis have shown the benefit of
probiotics in IBS
■ Shown benefit in overall symptoms, abdominal pain,
bloating and improve bowel habits (frequency,
consistency)
– Unclear if helps with specific constipation, diarrhea, gas but will help with general symptoms especially with bloating
- Help with gas production, bloating
- Improve feeling of discomfort in ab area
management IBS-C (constipation predominant)
fibre supplementation
– 15 - 20 gm per day (up to 30gm)
– start with lower 4 – 8 gm/day and titrate up (ie start with addition of fiber with one meal and then gradually increase the dose to 2 – 3 meals)
– soluble fiber in diet 3.4 g psyllium husk= 2.4 g soluble fiber
OR with
– bulk forming laxatives (ie psyllium, methylcellulose, polycarbophil, etc)
– avoid bran, contains both insoluble/soluble, but
insoluble fiber can cause bloating & worsen symptoms in some IBS patients
Titrate up
Dont want to giive too much fibre if discomfort
Natural soluble fibers could cause more gas for people, may switch to synthetic soluble fiber
management IBS-C (constipation predominant)
osmotic laxatives
– Consider if not controlled with fiber/diet.
Options:
– PEG
– lactulose
– glycerin suppositories- for immediate relief
Use if severe or prn use for quick relief
– magnesium citrate, hydroxide
– Stimulants (but may cause more cramping in some
patients with IBS)
management IBS-C (constipation predominant)
other agents: linaclotide
indication
AE
efficacy
Linaclotide (Constella®)
■ MOA: activates guanylate cyclase C receptor
■ Increases intestinal fluid secretions and motility
■ Indications: moderate to severe IBS-C
– Consider for patients who have not responded to other agents for IBS-C
■ 290 mcg oral once daily on empty stomach – 30
min before first meal (145 mcg for idiopathic
chronic constipation)
■ Efficacy: bowel symptoms improve within first week,
abdominal symptoms takes longer (4 wks)
■ Adverse effects: diarrhea, abdominal pain, flatulence,
abdominal distension
■CONTRA LESS THAN 6 YEARS OF AGE (not recommended less than 18)
management IBS-C (constipation predominant)
other agents: Prucalopride
– Could also consider in IBS-C for severe
constipation in women who have not responded to
other agents
5 HT4 agonist
management Diarrhea Predominant (IBS-D)
non-pharm
■ Diet: caffeine-free, lactose-free
– Avoid foods which worsen diarrhea (e.g. artificial
sweeteners)
■ Soluble fiber – acts as a bulking agent, can improve
global IBS symptoms
