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IRRITABLE BOWEL
SYNDROME
Kimberly M. Persley, MD
IBS – History
Earliest descriptions
of symptoms defining IBS

1849 – W Cumming1

– mucous colitis
– colonic spasm
– neurogenic mucous colitis
– irritable colon
– unstable colon
– nervous colon
– spastic colon
– nervous colitis
– spastic colitis
“The bowels are at
one time constipated,
at another lax, in the
same person.
How the disease has
two such different
symptoms I do not
profess to explain. . . .”
Other historical terms

1962 – Chaudhary & Truelove2
Irritable colon syndrome

1966 – CJ DeLor3
Irritable bowel syndrome
References: 1. Cumming. Lond Med Gazette. 1849;NS9;969-973. 2. Chaudhary and Truelove. Q J Med. July 1962;31:307-322.
3. DeLor. Am J Gastroenterol. May 1967;47:427-434.
IBS – History
Historical perspective

Long dismissed as a psychosomatic condition1
– no clear etiology
– affects predominantly women
(~70% of sufferers are women)2
– condition not fatal

Attitudes now changing

Incidence and prevalence not extensively
monitored in past
References: 1. Maxwell et al. Lancet. December 1997;350:1691-1695. 2. Sandler. Gastroenterology. August 1990;99:409-415.
IBS – Signs and symptoms
Hallmark symptoms of IBS

Chronic or recurrent GI symptoms
– lower abdominal pain/discomfort
– altered bowel function (urgency, altered stool
consistency, altered stool frequency, incomplete
evacuation)
– bloating

Not explained by identifiable structural or
biochemical abnormalities
Reference: Thompson et al. Gut. 1999;45(suppl 2):1143-1147.
IBS – Overview
Key facts about IBS

Up to 20% of the US population report symptoms
consistent with IBS1

The most common GI diagnosis among
gastroenterology practices in the US2

One of the top 10 reasons for PCP visits3

Affects predominantly females (~70% of sufferers)4

The most common functional bowel disorder5
References: 1. Camilleri and Choi. Aliment Pharmacol Ther. 1997;11:13-15. 2. Everhart and Renault. Gastroenterology. April
1991;100:998-1005. 3. Physician Drug & Diagnosis Audit (PDDA), April 1999, Scott-Levin. 4. Sandler. Gastroenterology. August
1990;99:409-415. 5. Thompson et al. Gastroenterol Int. 1992;5:75-91.
IBS – Overview
Key facts about IBS (cont.)





Can cause great discomfort, sometimes intermittent
or continuous, for many decades in a patient’s life1
Can significantly disrupt daily life2
Can have negative impact on quality of life2
Current treatment options3
– dietary modification
– fiber supplements
– pharmacologic agents
– psychotherapy
Success of current treatment options in addressing
multiple symptoms of IBS has been limited4
References: 1. Hahn et al. Dig Dis Sci. December 1998;43:2715-2718. 2. Hahn et al. Digestion. 1999;60:77-81. 3. Drossman.
Aliment Pharmacol Ther. 1999;13(suppl 2):3-14. 4. Klein. Aliment Pharmacol Ther. 1999;13(suppl 2):15-30.
IBS – Epidemiology
IBS consultation pattern
Specialists1
~25%
Consulters1
Primary care1
~75%
Nonconsulters1
~70%
Female2
~30%
Male2
References: 1. Drossman and Thompson. Ann Intern Med. June 1992;116(pt 1):1009-1016. 2. Sandler. Gastroenterology.
August 1990;99:409-415.
IBS – Epidemiology
IBS vs other
important disease states


US prevalence up to 20%1
US prevalence rates for other common
diseases2:
– diabetes
– asthma
– heart disease
– hypertension
3%
4%
8%
11%
References: 1. Camilleri and Choi. Aliment Pharmacol Ther. 1997;11:3-15. 2. Adams and Benson. Vital Health Stat 10.
December 1991:83. DHHS publication no (PHS)92-1509.
IBS – Burden of disease
Productivity burden
Absenteeism from work or school
during the last 12 months
14
Days per year
12
10
8
P=0.0001
6
4
2
0
IBS
Reference: Drossman et al. Dig Dis Sci. September 1993;38:1569-1580.
Non-IBS
Irritable Bowel Syndrome
Psychosocial
Factors
Vagal nuclei

Biopsychosocial Disorder
–
–
–
–


Psychosocial
Motility
Sensory
? Infectious
Sympathetic
S2,3,4
Altered
Motility
Altered
Sensation
Prevalence 10%, Incidence 1-2% per Year
Disturbs QOL, Social Function, Healthcare Utilization
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
References: 1. Bueno et al. Gastroenterology. May 1997;112:1714-1743. 2. Goyal and Hirano. N Engl J Med.
April 1996;334:1106-1115.
IBS – Pathophysiology
Physiological
distribution of 5-HT
CNS – 5%
GI tract – 95%
– enterochromaffin cells
– neuronal
Reference: Gershon. Aliment Pharmacol Ther. 1999;13(suppl 2):15-30.
IBS – Pathophysiology
5-HT receptor effects

Mediate reflexes controlling gastrointestinal
motility and secretion

Mediate perception of visceral pain
Reference: Gershon. Aliment Pharmacol Ther. 1999;13(suppl 2):15-30.
IBS – Physiology
Comparison of pain thresholds
of IBS patients and controls
Pain produced by rectosigmoid balloon distension
60
% Reporting Pain
IBS
40
20
Normal
0
20
60
100
140
Rectosigmoid balloon volume (mL)
Reference: From Whitehead et al. Dig Dis Sci. June 1980;25:404-413. With permission.
180
IBS – Physiology
Comparison of pain thresholds
IBS
Normal
Colonic Distension
Reference: Whitehead et al. Gastroenterology. May 1990;98:1187-1192.
Ice Water Immersion
IBS – Diagnosis
Make a positive diagnosis1,2
Identify abdominal pain as dominant
symptom with altered bowel function
Look for “red flags”
Perform diagnostic tests/physical exam
to rule out organic disease
Make/confirm diagnosis
Initiate treatment program as part
of diagnostic approach
Follow up in 3 to 6 weeks
References: 1. Paterson et al. Can Med Assoc J. July 1999;161:154-160. 2. American Gastroenterological Association.
Gastroenterology. June 1997;112:2120-2137.
IBS ROME II CRITERIA
 At
Least 12 Weeks, Which Need Not Be
Consecutive, in the Preceding 12
Months, of Abdominal Discomfort or
Pain That Has Two of Three Features:
1. Relieved with Defecation; and/or
2. Onset Associated with a Change
in Frequency of Stool; and/or
3. Onset Associated with a Change
in Form (Appearance) of Stool
Constipation
Diarrhea
IBS – Diagnosis
“Red flags” may suggest an
alternative or coexisting diagnosis
Additional diagnostic screening needed for atypical
presentations such as

Anemia

Fever

Persistent diarrhea

Rectal bleeding
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Severe constipation

Weight loss

Nocturnal symptoms of pain
and abnormal bowel function
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Family history of GI cancer,
inflammatory bowel disease,
or celiac disease

New onset of symptoms in
patients 50+ years of age
Reference: Paterson et al. Can Med Assoc J. July 1999;161:154-160.
IBS – Diagnosis
Diagnostic tests—What? When? Who?
If patient has typical features of IBS:


If 50 years of age, order CBC, electrolytes, LFTs,
screen stool for occult blood, and consider
sigmoidoscopy.1
If 50 years of age, order CBC, electrolytes, LFTs, and
perform a colonoscopy or air-contrast barium enema
with sigmoidoscopy.1,2
References: 1. American Gastroenterological Association. Gastroenterology. June 1997;112:2120-2137.
2. Paterson et al. Can Med Assoc J. July 1999;161:154-160.
IBS – Diagnosis
Differential diagnosis

Malabsorption1

Dietary factors1

Infection1

Inflammatory bowel disease1

Psychological disorders1

Gynecological disorders2

Miscellaneous1
References: 1. Drossman. Aliment Pharmacol Ther. 1999;13(suppl 2):3-14. 2. Moore et al. Br J Obstet Gynaecol.
December 1998;105:1322-1325.
IBS – Diagnosis
Current management of IBS

Establish a positive diagnosis1

Reassure patient that there is no serious
organic disease or alarming symptoms1

Success of current treatment options in
addressing multiple symptoms of IBS has
been limited2
References: 1. Drossman. Aliment Pharmacol Ther. 1999;13(suppl 2):3-14. 2. Klein. Gastroenterology. July 1988;95:232-241.
IBS – Management
Current management
components of IBS

Education

Reassurance

Dietary modification

Fiber

Symptomatic treatment

Psychological/behavioral options

Realistic goals
Reference: Drossman. Aliment Pharmacol Ther. 1999;13(suppl 2):3-14.
IBS – Management
Currently available
Rx treatments for IBS

Dicyclomine HCl1

Hyoscyamine sulfate
(± other anticholinergics/sedatives)2

Belladonna and phenobarbital1
Clidinium bromide with chlordiazepoxide1
 Tegaserod
 Alosetron

References: 1. PDR® Generics™. 1998:314, 559-561, 873-875. 2. Physicians’ Desk Reference®. 1999:2910-2911.
IBS – Management
Antispasmodics/anticholinergics
Symptomatic treatment—pain1

Smooth muscle relaxants via
anticholinergic effects and/or direct
action on smooth muscle2
References: 1. Drossman. Aliment Pharmacol Ther. 1999;13(suppl 2):3-14. 2. Drug Facts and Comparisons®. 1999:298-298c.
IBS – Management
Antidiarrheals
Symptomatic treatment—diarrhea

Increase stool firmness

Decrease stool frequency
– Examples: loperamide, diphenxylate-atropine
Reference: Drug Facts and Comparisons®. 1999:324b.
IBS – Management
Laxatives and bulking agents
Symptomatic treatment—constipation

Increased dietary fiber or psyllium1

Osmotic laxatives (MgSO4, lactulose)2

Stimulant laxatives3

Some laxatives and bulking agents can
exacerbate abdominal pain and bloating3
References: 1. American Gastroenterological Association. Gastroenterology. June 1997;112:2120-2132. 2. Camilleri and Choi.
Aliment Pharmacol Ther. 1997;11:3-15. 3. Drug Facts and Comparisons®. 1999:316-317a.
IBS – Management
Tricyclic antidepressants
and SSRIs
Symptomatic treatment—pain

Reserved for patients with severe
or refractory pain
Reference: Drossman and Thompson. Ann Intern Med. 1992;116(pt 1):1009-1016.
IBS – Management
Multiple medications needed
to treat multiple symptoms
Lower
abdominal pain
Bloating
Anticholinergics1
X
X
Tricyclic
antidepressants
and SSRIs2
X
Antidiarrheals1
Bulking agents1
Laxatives3
X
Altered
stool form
Altered
stool passage
Urgency
X
X
X
X
X
X
X
References: 1. American Gastroenterological Association. Gastroenterology. June 1997;112:2120-2137. 2. Drossman and Thompson.
Ann Intern Med. 1992;116(pt 1):1009-1016. 3. Drug Facts and Comparisons®. 1999:316.
INITIAL MANAGEMENT OF IBS
Symptom Features
Constipation
Diarrhea
Pain/Gas/Bloat
Review Diet History
Re: Fiber Intake
Yes
Yes
Additional Tests
No
H2 Breath Test
Celiac panel
Abdominal X-ray
(KUB During Pain)
Therapeutic Trial
Increase Fiber (20g),
Osmotic Laxative
Antidiarrheal
Antispasmodic
+ Antidepressant
Camilleri & Prather. 1992
Yes
Tegaserod (Zelnorm)
(serotinin 4 receptor agonist)
Approved for constipation predominant
IBS
 1 pill given twice daily
 Improvement of symptoms in women
but not men
 Use up to 12 weeks
 Mild side effects: diarrhea the most
prominent side effect

Non-Traditional Remedies

Chinese Herbal Medicine
– 116 pts randomized to CHM did better than pts
receiving placebo

Peppermint Oil
– Relaxation of GI smooth muscle
– Meta-analysis showed significant improvement
of IBS symptoms


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Acupunture
Probiotics
Antibiotics
Benoussan A. JAMA 1998
Pittler M. AJG 1998
Surgical Therapy for IBS

IBS symptoms may be attributed to:
– Non-functioning gallbladder disease,
chronic appendicitis, uterine fibroids,
tortuous colon
IBS symptoms rarely improve after
surgery
 IBS patients 2 to 3 times more likely to
undergo unnecessary surgery

Take Home Points
IBS is a chronic medical condition
characterized by abdominal pain,
diarrhea or constipation, bloating,
passage of mucus and feelings of
incomplete evacuation
 Precise etiology of IBS is unknown and
therefore treatment is focused on
relieving symptoms rather that “curing
disease”

Take Home Points
Although many IBS patients complain
of symptoms after eating, true food
allergies are uncommon
 Specific therapies are determined by
individual patient symptoms
 Life-style modifications and possible
alternative therapies may relieve
symptoms
 Surgery has NO Role in treatment of IBS
