IBS kimberly

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 – Physiology
Comparison of pain thresholds of IBS patients and controls
60
Pain produced by rectosigmoid balloon distension
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%
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.
– – – –
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

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 – Burden of disease
Productivity burden
Absenteeism from work or school during the last 12 months 14 12 Days per year 10 8 6 4 2 0 P=0.0001
IBS
Non-IBS
Reference: Drossman et al. Dig Dis Sci. September 1993;38:1569-1580.
Irritable Bowel Syndrome
Psychosocial Factors
Vagal nuclei

Biopsychosocial Disorder

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
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.

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
“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. . . .”
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 – Pathophysiology
Βιβλιοθήκη Baidu
Physiological distribution of 5-HT
CNS – 5%
– enterochromaffin cells – neuronal
GI tract – 95%
Reference: Gershon. Aliment Pharmacol Ther. 1999;13(suppl 2):15-30.




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 – 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
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
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.
IRRITABLE BOWEL SYNDROME
Kimberly M. Persley, MD
IBS – History
Earliest descriptions of symptoms defining IBS

1849 – W Cumming1

Other historical terms
– mucous colitis – colonic spasm – neurogenic mucous colitis – irritable colon – unstable colon – nervous colon – spastic colon – nervous colitis – spastic colitis
– 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.