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
