IRRITABLE BOWEL SYNDROME (IBS) CHRONIC CONSTIPATION Susan Lucak, MD
June 13, 2017 | Author: Kory Cross | Category: N/A
Short Description
1 IRRITABLE BOWEL SYNDROME (IBS) CHRONIC CONSTIPATION Susan Lucak, MD2 IBS: Definitions Functional disorder=absence of o...
Description
IRRITABLE BOWEL SYNDROME (IBS) CHRONIC CONSTIPATION Susan Lucak, MD
IBS: Definitions IBS: Definitions • Functional disorder=absence of organic abnormalities, i.e. no discernible biochemical or structural changes • Syndrome not Disease complex biopsychosocial disorder of disorder of • A complex biopsychosocial unknown cause, characterized by abdominal pain/discomfort and bowel irregularities (C D pain/discomfort and bowel irregularities (C, D, C/D), gut interacts withCNS
IBS: Epidemiology IBS: Epidemiology Up to Up to 22% Americans report IBS Sxs 22% Americans report IBS Sxs ~70% IBS patients are women Age : less than 40 l h 0 Not directly lethal, associated with suicidality (SI, SA, suicides) p Q y ( , p ) • Impacts on Quality of Life (~DM, depression) • Reduces productivity (13.4 v. 4.9 days missed at work) at work) • • • •
Pathophysiology of IBS Proposed Pathophysiology of IBS Acute Gastroenteritis
• Gastrointestinal (GI) Motor Disturbances
Food
• Visceral Hypersensitivity
Genetic Factors Environment Abuse History Other Precipitating Factors
• Abnormal Central Processing of Sensations • Psychological Disturbances
Symptoms
Stress
Consultation
Adapted from Rome Foundation Functional GI Disorders Specialty Modules.
IBS: Pathophysiology, Predisposing Factors Genetic Factors IBS aggregates in some families Gene polymorphisms: 5‐HT, IL‐10, COMT – pain sensitivity Twin studies : monozygotes – increased concordance Environmental Factors – Early Life Children of adults with IBS, more health care visits, social learning of illness behavior Children with recurrent abdominal pain, higher levels of anxiety + depression, more Sxs Abuse Historyy Sexual, physical abuse (30‐56% in referral centers in US + Europe, less frequent in primary care centers) Childhood abuse (~50%) Ab Abuse affects health outcomes (more severe pain, greater impairment in ff h lh ( i i i i functioning Precipitating Factors – Adult Life Breakup of a relationship Breakup of a relationship Stressful life events (war, loss of loved one) Chronic life stress (unhappy marriage, war), more severe Sxs
IBS:Pathophysiology, Brain‐Gut Interactions + Other Possible Modifying Factors Other Possible Modifying Factors Enhanced perception Psychosocial factors
Food
Altered motility
Genetic predisposition
5‐HT
Infection / inflammation
Visceral hypersensitivity Adapted from Camilleri et al, Aliment Pharmacol Ther 1997; 11: 3
IBS: Functions of the GI tract‐outline IBS: Functions of the GI tract outline Chemical/physical stimulation in the mucosa releases mediators, stimulate intrinsic neurons in ENS, afferent nerves synapse with: Sensory: afferent neurons to spinal cord, to brain, • Sensory: afferent neurons to spinal cord, to brain, descending inhibitory pathways back to ENS • Motor: interneurons,in ENS, synapse with motor neurons in ENS peristalsis (cycles of contraction+ neurons in ENS, peristalsis (cycles of contraction+ relaxation) • Secretory: interneurons, release of mediators stimulate chloride secretion i l hl id i • Mediators: 5‐HT, tachykinins, CGRP, enkephalins, Ach, NO, substance P, VIP, cholecystokinin , , , y
CNS Activation (fMRI) of Normals and IBS Subjects to Rectal Distension
IBS: Brain functional MRI during rectal distention, differential activity in IBS v. C
IBS
80
IBS Controls 60
Active pixels (# per ROI) 40
*
Control PFC ACC IC Thalamus
20
0 Prefrontal
Mertz et. al., Gastroenterology 2000; 118:842
Insula
ACC
Thalamus
Descending Pain Pathways
Descending Visceral Pain Pathway
ACC
Thalamus PAG Locus coeruleus Amygdala
Caudal raphe nucleus
Noradrenergic
Rostral ventral medulla
Serotonergic Opioidergic
Colon
IBS: Pathophysiology Secretion via Chloride Channels hl d h l Luminal
Abluminal K+ CI– Na+
Cl– channel
CI–
Na+
~
K+
K+
Na+/K+/2CI– Cotransporter Na+ pump N K+ channel
Na+ paracellular path
Adapted from Cuppoletti J, et al. Am J Physiol Cell Physiol. 2004;287:C1173‐C1183.
IBS: Pathophysiology, Secretion via Chloride Channels (ClC‐2) i i hl id h l ( l )
Pathophysiology of IBS Proposed Pathophysiology of IBS Acute Gastroenteritis
• Gastrointestinal (GI) Motor Disturbances
Food
• Visceral Hypersensitivity
Genetic Factors Environment Abuse History Other Precipitating Factors
• Abnormal Central Processing of Sensations • Psychological Disturbances
Symptoms
Stress
Consultation
Adapted from Rome Foundation Functional GI Disorders Specialty Modules.
Gut Flora in IBS Postinfectious IBS (PI IBS) Postinfectious IBS (PI‐IBS)
SIBO
Normal Intestinal Microflora Duodenum 101–103 cfu/ml
1011–1012
Stomach 101–103 cfu/ml
Colon cfu/ml Jejunum/ileum 104–107 cfu/ml
Most common bacteria Anaerobic genera
Aerobic genera
Bifidobacterium
Escherichia
Clostridium
Enterococcus
Bacteroides
Streptococcus
Eubacterium
Klebsiella
O’Hara AM. EMBO Rep. 2006;7:688‐693.
• 10 10 trillion nonpathogenic trillion nonpathogenic bacteria in bacteria in the GI tract (1‐2 kg) • Exert protective function by creating a barrier against pathogenic by producing various anti‐microbial factors • Influence the development and f ti function of the mucosal immune f th li system
Risk of PI‐IBS Increases 7‐fold After Infectious Gastroenteritis* Protective Effect
Increased Risk
Study (year/bacteria)
OR (95% Cl)
Ji (2005/Shigella)
2.8 (1.0‐7.5)
Mearin (2005/Salmonella)
8.7 (3.3‐22.6)
W Wang ( (2004/Unspecified) / ifi d)
10 7 (2 5 45 6) 10.7 (2.5‐45.6)
Okhuysen (2004/Unspecified)
10.1 (0.6‐181.4)
Cumberland (2003/Unspecified)
6.6 (2.0‐22.3)
llnyckyj (2003/Unspecified)
2.7 (0.2‐30.2)
Parry (2003/Bacterial NOS)
9.9 (3.2‐30.0)
Rodriguez (1999/Bacterial NOS)
11.3 (6.3‐20.1)
Pooled estimate
7.3 (4.8‐11.1) 0.1 0.5 1 10 50
OR
*Systematic review of 8 studies involving 588,061 subjects; follow‐up ranged from 3 to 12 months. Halvorsen HA et al. Am J Gastroenterol. 2006;101:1894‐1899.
9.8% IBS in cases vs 1.2% IBS in controls
Increased Inflammatory Cells Found in PI‐IBS Rectal Biopsies
Ente eroendocrine Ce ell Countss/100 Epithelial Cells
30
CD8 Lymphocyte Counts
A *
* 20
* *
10
0
Visit 1
Visit 2
Visit 3
Control
PI‐IBS‡
Intraepitheiial CD8 Lymphocytes/100 EEpithelial Cells
Enteroendocrine Cells 8
6
*
4
†
2
0
Visit 1
Visit 2
Visit 3
Levels at 52 wk Levels at 52 wk
25th to 50th Percentile 50th to 75th Percentile Median (50th Percentile)
*P
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