1. health and fitness
2. disease

Chronic Abdominal Pain
New thoughts on the sensitive gut
John T. Boyle, M.D.
Educational Objectives
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Learn an algorithm for evaluation of chronic
abdominal pain
Define diagnostic criteria for functional
abdominal pain
Review current concepts of pathophysiology
Establish goals of therapy
Evaluate current treatment options
Ambiguity of Terms
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Chronic abdominal pain
• In clinical practice, it is generally believed that
abdominal pain that exceeds 1 or 2 months can be
considered chronic
• In population studies, chronic abdominal pain is
reported to occur in 10-15% of all children
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Recurrent abdominal pain (Seminal definition by Apley in 1958
• Paroxysmal abdominal pain in children between the
ages of 4 and 16 years
• Persists for more than 3 months
• Affects normal activity
• Has been equated in the literature as a diagnosis
Recurrent Abdominal Pain (RAP)
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RAP is not a diagnosis
RAP should be considered a synonym for
chronic abdominal pain
The key concept when thinking about chronic
abdominal pain is pain that affects normal
lifestyle
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School attendance
Ability to focus in school
Participation in extracurricular activities
Feeding behavior
Sleep pattern
Differential diagnosis of
Chronic Abdominal Pain
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Organic pain
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Anatomical disorders
Infectious
Non-infectious inflammatory bowel disease
Biochemical abnormalities
Psychosomatic pain
• Primary factors that influence the perception of pain are
cognitive and emotional
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Functional abdominal pain
• Dysfunction of the autonomic nervous system in the
gastrointestinal tract
Traditional Concept of
Functional Bowel disease
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A negative diagnosis
No specific structural, infectious,
inflammatory, biochemical, or
psychosomatic cause can be
determined
Frequency of Diagnosis
Organic
Psychogenic
Psychogenic
Functional
Organic
Functional
Key Concepts in Approach to
Chronic Abdominal Pain
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Functional abdominal pain should not be a
diagnosis of exclusion
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Primary care physicians should be able to make
a primary diagnosis of functional abdominal pain
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A large battery of biochemical and x-ray tests
should not be necessary in the majority of
patients who present with recurrent abdominal
pain
Algorithm for Evaluation of
Chronic Abdominal Pain
Value of the Pain History in Differentiating
Organic from Functional Abdominal Pain
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The characteristics of the pain itself do not allow
the physician to discriminate between organic,
functional, or psychosomatic disorders
Frequency of pain
Character of pain
Location of pain
Pain awakening patient at night
Associated GI symptoms including anorexia,
nausea, vomiting, increased gas, or altered bowel
• Associated extra-intestinal symptoms including
fatigue, headache, arthralgia
• Affects of pain on lifestyle
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Algorithm for Evaluation of
Recurrent Abdominal Pain
The Presence of Alarm Signals Should
Trigger Work-Up of Organic Disorder
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Involuntary weight loss
Growth retardation
Significant vomiting
Significant diarrhea
GI blood loss
Consistent RUQ or RLQ abdominal pain
Associated fever, arthritis, rash, amenorrhea
Symptoms of psychiatric disorder
Family history of inflammatory bowel disease
Abnormal physical exam
Abnormal Physical Findings
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Localized tenderness in RUQ or RLQ
Localized fullness or mass
Hepatomegaly
Splenomegaly
Spine or CVA tenderness
Perianal fissure or fistula
Visible soiling
Guaiac positive stool
Algorithm for Evaluation of
Recurrent Abdominal Pain
Algorithm for Evaluation of
Recurrent Abdominal Pain
Sub-categories of Functional Abdominal
Pain Based on Distinctive Clinical Features
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Isolated abdominal pain (Functional abdominal pain)
Dyspepsia (Functional dyspepsia)
• Usually epigastric pain, associated with eating, nausea,
episodic vomiting, early satiety, bloating,
occasional heartburn, or oral regurgitation
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Irritable bowel syndrome
• Pain associated with change in frequency or
consistency of bowel movements, pain relieved by
defecation, or a sense of incomplete evacuation after
bowel movement
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Abdominal migraine
• Cyclical pain associated with nausea, vomiting, pallor,
headache, or photophobia as well as a family history of
migraine
Personal Experience at Rainbow Babies
& Children’s Hospital
Isolated Pain Dyspepsia
# Patients
% of Total
Mean age
% Male
% Functional
59
19%
8.9 yrs
39%
85%
128
40%
11.1 yrs
46%
77%
Irritable
Bowel
132
41%
9.1yrs
42%
66%
Diagnostic Testing May Be Considered:
To reassure the parent, patient, or
physician
„ To support the absence of organic
disease if it is believed that the pain
significantly diminishes the quality of life
of the patient
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Major Organic Etiologies of Isolated
Chronic Abdominal Pain
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Unrecognized constipation
Gastroesophageal reflux disease (young children)
Parasitic infection
Crohn’s disease
Musculoskeletal disorders
Partial small bowel obstruction (malrotation, postsurgical adhesions, lymphoma
Infection (tuberculosis, yersinea)
Endometriosis
Occult urinary tract infection
Acute intermittent porphyria
Reasonable Diagnostic Evaluation of Isolated Chronic
Abdominal Pain in the Absence of Alarm Signals
Stool guaiac
„ CBC with differential
„ ESR
„ Urinalysis
„ Stool O & P
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Major Organic Etiologies of Abdominal Pain Associated
with Symptoms of Dyspepsia
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Helicobacter pylori gastritis
Peptic ulcer
Gastroesophageal reflux disease
Choledocholithiasis
Relapsing pancreatitis
Crohn’s disease
Parasitic infection
Malrotation
Reasonable Diagnostic Evaluation of Dyspepsia in
the Absence of Alarm Signals
Stool guaiac
„ CBC with differential
„ ESR
„ H. pylori serology or stool antigen
„ Comprehensive metabolic panel
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Vomiting is a Key Variable which
Expands the Differential Diagnosis
Malrotation/ other anatomical GI
disorders
„ Crohn’s disease
„ Gallstones
„ Hydronephrosis
„ Pancreatic cyst
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Reasonable Diagnostic Evaluation of Dyspepsia Where
There is Concern About the Frequency of Vomiting
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Stool guaiac
CBC with differential
ESR
H. pylori serology or stool antigen
Comprehensive metabolic panel
Amylase/lipase
UGI-SBFT
Abdominal Ultrasound
Major Organic Etiologies of Abdominal Pain
Associated with Altered Bowel Pattern
Chronic fecal retention
„ Parasitic infection
„ Chronic C. difficile enteritis
„ Lactose intolerance
„ Inflammatory bowel disease
„ Celiac disease
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Reasonable Diagnostic Evaluation of Abdominal Pain with
Altered Bowel Pattern in the Absence of Alarm Signals
„ Stool
guaiac
„ CBC with differential
„ ESR
„ Stool for O & P
„ C. difficile toxin
„ Celiac panel
„ Lactose breath test
Algorithm for Evaluation of
Recurrent Abdominal Pain
Pathophysiology of
Functional Abdominal Pain
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Exact etiology and pathogenesis are
unknown
Genetic vulnerability
Most children “outgrow” symptoms,
suggesting a developmental component
Current speculation on pathogenesis:
dysfunction of the autonomic nervous
system in the gastrointestinal tract
• Disordered gastrointestinal motility
• Visceral hypersensitivity
• Central excitability
Autonomic Dysfunction in Children
with Functional Abdominal Pain
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Disordered motility
• Increased intensity of intestinal muscle contraction
• Increased or decreased intestinal transit
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Visceral hypersensitivity
• Increased visceral perception → felt as pain
• Potential mechanisms:
– Reduced threshold of gut wall afferent sensory receptors
– Stress factors that reduce set point at which visceral
afferent fibers are stimulated
Autonomic Dysfunction in Children
with Functional Abdominal Pain
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Central excitability
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Increased central perception felt as pain
Potential mechanisms:
– Amplification of sensory traffic as it travels
from gut to brain
– Altered conscious threshold in the central
nervous system triggered by convergent
somatic inputs
Rectal and Gastric Hyperalgesia in Children
with RAP (DiLorenzo et al. Gastroenterology, 1998)
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Visceral pain perception was measured in the
stomach and rectum using an electronic barostat in
15 pts with RAP and 10 age-matched controls
RAP Control p-value
Rectal pain threshold (mmHg) 28.4
Stomach pain threshold (ml)
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187
37
287
<0.05
<0.07
Conclusion: Children with RAP have generalized
visceral hyperalgesia
Consequences of Reduced Threshold of Gut
Wall Sensory Afferent Receptors
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Painful sensations may be provoked by
physiologic stimuli
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Postprandial gastric or intestinal distention
Gastric emptying
Intestinal contractions or migrating motor complex
Gastroesophageal reflux
GI gas
Minor noxious irritants such as spicy foods
Physical stress factors that may reduce set point
at which visceral afferent fibers are stimulated
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Recent physical illness
Lactose intolerance
Other food intolerance (e.g. fructose, sorbitol)
Aerophagia
Mucosal inflammation (H. pylori gastritis)
Celiac disease
Side effects of drug therapy (e.g..
antibiotics)
Simple constipation
Psychological stress factors that may alter
conscious threshold in the central nervous system
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Death of significant family member
Separation of significant family member
Physical illness or chronic handicap in
parents or sibling
School problems
Altered peer relationships
Family financial problems
Recent geographical move
Goals of Treatment of
Functional Abdominal Pain
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The focus of treatment is not “cure” or rapid
recovery, but rather management of
symptoms and adaptation to illness
Outcome variables
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School attendance and performance
Participation in extracurricular activities
Normal sleep pattern
Normal weight gain and growth
Pain frequency and severity
Treatment of
Functional Abdominal Pain
Make a positive, confident diagnosis
„ Explain pathophysiology, natural
history, and goals of therapy
„ Dietary modification
„ Drug therapy
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• No proof that any drug regimen is effective for all
patients with functional pain
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Psychological support
Explanation of the Mechanism of
Functional Abdominal Pain
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Legitimize symptoms: The pain is real
Equate pain to “headache”
Differentiate voluntary from involuntary
(autonomic) processes
Explain the role of the autonomic nervous system
• “You don’t have to tell your heart to beat”
• “You don’t have to tell the blood to circulate through
the body”
• “You don’t have to tell your intestines to work”
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Explain the concept of autonomic dysfunction
Explanation of the Mechanism of
Functional Abdominal Pain
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Normal sensitivity
threshold – rarely feel
muscle contractions
Sensitivity threshold of
patients is reduced –
patient perceives
muscle activity as pain
Stress factors lower the
sensitivity threshold
increasing the
frequency and intensity
of pain
Explanation of Goal of Therapy of
Functional Abdominal Pain
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Identify and reduce
stress factors
Use diet, medication,
and cognitive behavioral
therapy to raise the
visceral and central
sensitivity threshold
Pharmacological modulation of
gastrointestinal motor abnormalities
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Antispasmodics aimed at reducing the
force of smooth muscle contractions
• hyoscyamine, dicyclomine, glycopyrrolate,
peppermint oil, calcium channel blockers
• work best for postprandial abdominal pain
• high side effect profile at higher doses that are
effective in pain relief
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Fiber supplements
• increase propulsive activity, reduce segmenting
myoelectric activity, enhance water-holding
properties and bulk of stool
Pharmacological modulation of factors
that may exaggerate visceral perception
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Gastric acid
• Antisecretory agents (H2RA’s or PPI’s)
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Intestinal gas
• Antigas preparations (simethicone,
activated charcoal, lactase, Beano)
• Lactase enzymes for patients wih lactose
intolerance
Low-dose tricyclic antidepressants to
treat functional abdominal pain
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Control abdominal pain symptoms whether or
not a psychiatric illness is identified
Doses that reduce pain are below usual
psychiatric dosages
Mechanism of action unknown
• do not seem to affect visceral afferent
sensation thresholds
• May effect central processing of visceral
afferent traffic
Low-dose tricyclic antidepressants to
treat functional abdominal pain
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Negligible potential for dependency
TCAs are more sedating and this property
may help some patients with sleep disorders
High side-effect profile including
constipation, sedation, restlessness, weight
gain, impaired cognitive function
As with cisapride, may prolong QTc interval
5-HT4 receptor agonist
Tegaserod (Zelnorm)
„ Received FDA approval for women with
severe constipation-predominant IBS
„ Binds to 5-HT4 receptors, stimulating GI
peristalsis and decreasing visceral
sensitivity
„ Not released for children in the U.S.
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5-HT3 receptor antagonist
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Alosetron HCl (Lotronex)
Received FDA approval for Rx of IBS in women with
abdominal pain & diarrhea
Inhibits activation of type 3 serotonin (5-HT3 )
receptors on GI tract neurons decreasing intestinal
secretion, motility, and afferent pain signals
41% of patients taking alosteron reported relief of
abdominal pain compared to 29% taking placebo
Not released for children in the U.S.
Psychological and Behavioral Treatment of
Functional Bowel Disease
Relaxation techniques
„ Coping strategies
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• Cognitive behavioral therapy
• Hypnotherapy
• Psychotherapy
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Finding appropriately trained mental
health providers is difficult
Factors That Affect Prognosis of
Functional Abdominal Pain
Factor
Family
Gender
Age of Onset
Period before
Treatment
Apley J, Hale B
Prognosis
Better
Normal
Female
>6 years
< 6 months
Brit Med J 3:7, 1973
Prognosis
Worse
“Painful”
Male
<6 years
> 6 months