Transcript L4_IBS

IRRITABLE BOWEL SYDNROME
IBS - Definition
• Altered bowel habit and/or
• Abdominal discomfort or pain
• No demonstrable organic disease
As no marker exists for IBS,
diagnosis is based on clinical features
Summary of Hypotheses on
the Pathophysiology of IBS
• IBS is characterized by changes in motility in
response to environmental or enteric stimuli1
• Visceral hypersensitivity is well documented in IBS
patients2
• Serotonin, which has both motility and sensory
modulating properties, could represent a common
factor linking the symptoms of IBS3
Epidemiology - 1
• 6-22% of the North America population have seen a
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physician for IBS symptoms
Most cases diagnosed before age 45 but IBS is
sometimes diagnosed in those above 65 years
Women are 3 times more frequently affected than
men
Less common in Asians & Hispanic than Caucasians
Epidemiology - 2
• 6-22% of population report symptoms but only about
1/5 to 1/3 of these seek medical care
• Factors associated with physician consultations:
–Personality disorders or depression
–Long duration of symptoms
Impact on Society - 1
• Visits to the doctor:
– 12% primary care
– 28% gastroenterologist
• Health care costs:
– Twice that of an asymptomatic person
– More appendectomies, cholecystectomies
and hysterectomies in those with IBS
IBS – Pathophysiology
IBS: Current thinking on pathophysiology
Defects in the enteric nervous system may lead
to the hallmark symptoms of IBS.
• Visceral hypersensitivity1
– Increased visceral afferent response to normal as well
as
noxious stimuli
– Mediators include 5-HT, bradykinin, tachykinins, CGRP,
and
neurotropins
• Primary motility disorder of GI tract2
– Mediated by 5-HT, acetylcholine, ATP, motilin, nitric
oxide,
somatostatin,
substance P, and VIP
IBS – Pathophysiology
5-HT receptor effects
• Mediate reflexes controlling
gastrointestinal motility and secretion
• Mediate perception of visceral pain
Impact on Society - 2
• Impairment of QOL: worse than in patients with DM
or CRF
• Time off work: 3 times more often than that for an
asymptomatic person
• Restriction of activities: by 145 days per year
Rome II Criteria for Diagnosis
• Symptoms for at least 12 weeks (which need not be
consecutive), in the preceding 12 months:
• Abdominal pain or discomfort, which has 2 of the 3
following features:
Rome II Criteria - continued
1. Pain relieved with defecation; or
2. Altered bowel habit associated with a change in the
frequency of stools; or
3. Altered bowel habit associated with a change in the
form (appearance) of the stools
Rome II Criteria - continued
Other symptoms that cumulatively support the
diagnosis of IBS include the following:
1. Abnormal stool frequency (>3BMx/d or <3BMs/wk)
2. Abnormal stool form (lumpy and hard or loose and
3.
4.
5.
watery)
Abnormal stool passage (straining, urgency, feeling
of incomplete evacuation)
Passage of mucus
Bloating or feeling of distention.
Frequency of Symptoms
In 154 consecutative patients diagnosed as
IBS in a GI unit, there was
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Abdominal discomfort or pain 33% of days
Bloating 28% of days
Altered stool form 25% of days
Altered stool frequency 18% of days
Passage of mucus 7% of days
Abdominal Pain
Intensity, location and characteristic of pain is highly
variable
– epigastric 10%
– right side 20%
– left sided 20%
– hypogastric 25%
– too variable 25%
• Cramping or an ache
• Post-prandial worsening of pain for 1-3 hours
• Stress or emotional turmoil worsens condition
• Worse before and/or during menstruation
Altered Bowel Habit
• Constipation-predominant
––hard pellet-like stools, infrequent (<1/day)
• Diarrhea-predominant
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frequent loose stools
post prandial
urgency
straining
incomplete evacuation
mucoid discharge – 50%, no blood
Symptom Associations
• UGI – dyspepsia, heartburn, early satiety, nausea,
all are more frequent in constipationpredominant IBS
• LGI – abdominal distention, bloating – more in
women
• GUS – pelvic pain, dysmenorrhea, dyspareunia,
urinary frequency, nocturia, incomplete
bladder evacuation
• MSK – fibromyalgia, back pain, head & neck pain
Other Associations
• Increased risk of PUD, HBP, sicca syndrome &
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vague rashes
Triad of IBS, GERD & Asthma is 3-times more
frequent than expected
‘Red Flags’ - Alarm Symptoms/Signs
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Onset after 55 years
Persistent anorexia & weight loss > 10 lbs
Persistent “fever” in the evening
Pain – changing pattern or increasing after
food and persisting for a few hours
Awakened by pain &/or diarrhea at night
Rectal bleeding, not just on wiping
Stools “like malabsorption syndrome”
P/E: palpable mass in the abdomen
Differential Diagnosis
1.
2.
3.
4.
5.
6.
Dietary – e.g. lactose intolerance.
Infections – Giardia, Bacterial Overgrowth Syndrome
Inflammatory Bowel Disease – UC, CD
Malabsorption syndrome – Celiac Disease, Pancreatic
Insufficiency
Psychological – Depression Anxiety
Other - Neuroses
Diagnosis - 1
Approach: before doing any tests:
1. Gain the confidence of the patient at the first
consultation, let them talk and just listen
2. Remain aware that some IBS patients have a
hidden agenda
3. Do not say to the patient what some FPs say,
namely, “I don’t know what is wrong with you”
4. Do not say what some Specialists say, namely:
“There is nothing wrong with you” or “it is in your
head”
Diagnosis - 2
5. Get all the test reports from the other MDs files and
6. Show & discuss those test results with the patient
7. In those below 55 yrs and in the absence of “alarm
symptoms”, if “routine” blood tests + ESR/CRP are
normal, diagnosis of IBS has:
8.
- 83% sensitivity
- 97% specificity
- 100% PPV
Therefore, please do these tests
Diagnosis - 3
• I ask the patient; “which single GI disease do you
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think you may have?” and I do one test first to
exclude that and review the patient after the test:
In my experience:
Pain
Diarrhea
Constipation
<50 yrs
PUD, CD
LI, MAS, “obstruction”
>50 yrs
GBD, CRC
CRC
are the commonest cause of anxiety for the patient
Diagnosis - 4
Two multicentre trials have found the following
associations:
• Lactose Intolerance
• “Structural abnormality”
• Abnormal thyroid tests
• Stools O&P
23%
2%
6%
2%
Diagnosis - Summary
• IBS remains a clinical diagnosis.
• In those below 55 years and in the absence of
alarm symptoms, Rome II Criteria (Clinical) has:
- Sensitivity 65%
- Specificity 100%
- PPV
100%
-No diagnosis revision during 2 yr follow up
Vanner etal (1999) Amer J Gast 94:2912
Traditional therapies focused on
individual symptoms of IBS with
and distention
constipation Bloating

Abdominal pain / discomfort
 Antispasmodics
 Tricyclics
 Analgesics
Abdominal
pain /
discomfort
Irregular Bowel
Habit
 Fiber
 Laxatives
 Imodium
Bloating /
distention
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Dietary modifications
Antispasmodics
Antiflatulants
Digestive enzymes
Antibiotics
Constipation
or Diarrhea
 None of these medications effectively treat the multiple symptoms of IBS.
May exacerbate individual symptoms e.g., fiber and bloating; antispasmodics and constipation