Pediatricians frequently see patients with chronic abdominal pain. In most
children, chronic abdominal pain is functional, that is, without demonstrable
evidence of an underlying pathologic condition, such as an anatomic, infectious,
inflammatory, metabolic, or neoplastic disorder. The pain-predominant functional
gastrointestinal disorders (PP-FGIDs) include functional dyspepsia, irritable
bowel syndrome (IBS), abdominal migraine, childhood functional abdominal pain
and childhood functional abdominal pain syndrome. A child with PP-FGID is
usually in distress, the parents are troubled with the recurrent symptoms, and
the physician is concerned about ordering investigations to avoid missing
serious disease. Managing these conditions also can present considerable
challenges in terms of explaining the etiology and lack of proven therapy. This
article will review the current understanding of PP-FGIDs to help pediatricians
counsel families and guide treatment decisions.
Definition
Five decades ago, Apley and Naish described children who presented with at
least 3 abdominal pain episodes interfering with their daily functioning over at
least 3 months as having recurrent abdominal pain (RAP).[1] Later studies showed
that this was a "waste basket" term. RAP is a symptom rather than a diagnosis.
Although 90% of the patients with RAP have a functional gastrointestinal
disorder (FGID), some of these children have an organic condition requiring
different diagnostic and therapeutic approaches.
Currently, the Rome II criteria define FGIDs in children as chronic
gastrointestinal conditions without clinical evidence of anatomical or
structural abnormalities. The latest edition of the Rome criteria defines 5
pain-predominant FGIDs (PP-FGIDs): functional dyspepsia, IBS, abdominal
migraine, childhood functional abdominal pain and childhood functional abdominal
pain syndrome (Table 1).[2-4]
Importance
PP-FGIDs are very common in children. These disorders represent 2% to 4% all
of pediatric office visits.[5] Approximately 38% of school children complain of
abdominal pain weekly.[6] Six percent of middle school students and 14% percent
of high school students have IBS symptoms.[7] Furthermore, studies at the
doctor's office misrepresent the enormity of the problem, as only 3% of all
children complaining of abdominal pain at the community level seek
consultation.[8] Abdominal pain is associated with worse quality of life, school
absenteeism, and higher anxiety and depression scores.[9] Children with a
history of PP-FGID also have higher prevalence of psychiatric conditions,
socialization problems and use of medications as adults.[10] The estimated
financial burden of chronic abdominal pain is substantial, with the expenses
associated with treatment of IBS alone ranging between $8 billion to $30 billion
per year in adult patients.
Pathophysiology
Although the pathophysiology of PP-FGIDs remains unclear, recent developments
have contributed to the understanding of these conditions. Pathophysiology of
PP-FGIDs is thought to involve abnormalities at multiple levels of the enteric
nervous system (ENS) or the "little brain in the gut," and the central nervous
system (CNS). Dysregulation of the bidirectional communication between ENS and
CNS plays a key role in the pathogenesis of PP-FGIDs. Although some patients
with PP-FGIDs present with gastrointestinal motor abnormalities, these are
rarely related temporally with the pain episode or not severe enough to account
for the patients' symptoms.
Research suggests that children with PP-FGIDs may have an abnormal reaction
to different physiologic and pathologic stimuli affecting the gut: distension,
meals, hormonal changes, inflammatory processes, as well as psychological
stressors such as anxiety or problems with parents and school.[11] Evidence also
suggests that PP-FGIDs may be associated with visceral hyperalgesia, including
hypersensitivity (lower threshold to pain) and allodynia (a painful response to
a usually non-painful stimulus). Adult studies in patients with IBS show
abnormal processing of pain, with amplification of pain, failure to
down-regulate pain and involvement of emotional and stress related areas in
response to painful gut stimuli.[12]
Some studies have linked bacterial and viral infections to the onset of IBS
in children and adults.[13,14] The associated mucosal inflammatory processes may
cause afferent nerve sensitization that leads to visceral hyperalgesia.
The concept of visceral hyperalgesia can be explained to patients and family
members by comparing it to skin sensitization after a burn. Even mild stimuli,
such as contact with clothes, may be painful for a long time after a burn.
Children also may be predisposed to develop a PP-FGID. Twin studies seem to
indicate that there is a genetic predisposition, but at this time no gene has
been isolated that could explain most of the cases of PP-FGIDs.[15]
Predisposition also could be due to early sensitization or other unknown
reasons.
The most accepted framework to explain PP-FGIDs is the biopsychosocial model.
It proposes that there is no single etiology for these conditions. PP-FGIDs
result from the interplay of different factors including biological,
psychological and social. This is an important concept, not only to explain the
pathogenesis of these conditions, but also to select an appropriate treatment
modality for each individual patient.
Diagnosis
Functional abdominal pain is the most common cause of chronic abdominal pain.
PP-FGIDs are clinically diagnosed based on parent and child's reports of
symptoms using the Rome criteria (Table 1). No tests will provide elements for
diagnosis as there are no biological markers to characterize a functional
condition.
However, it is generally accepted that a limited battery of tests could be
conducted for reassurance, especially if the pain is severely affecting the
quality of life of the patient and family. If any alarm symptoms (Table 2) are
present, selected testing to rule out anatomic, infectious, inflammatory or
metabolic conditions is indicated.
When tests are ordered, parents should be told that negative results are
expected. A negative result does not mean that more testing is needed, but
instead confirms the diagnosis of PP-FGIDs. Extensive or repeated testing
frequently confuses parents and may provide an impression that the practitioner
is lost in the diagnostic process.
Providing reassurance
Managing chronic painful conditions is challenging. It requires extensive
patience and time. Counseling and reassurance play an important role in
management of PP-FGIDs. Parents are frequently frustrated and many times
disappointed with past investigations and treatments. They frequently change
physicians to get a satisfactory answer about their child's medical
condition.
It is important to regain the parents' trust. The practitioner can give
families more confidence by discussing with them the proposed pathogenesis of
PP-FGIDs and criteria for the diagnosis. One effective strategy is to show
parents the Rome criteria and ask them to verify whether the child's symptoms
correspond to any of the diagnoses listed. Naming the condition brings comfort
to worried parents who are concerned that the child "may have something bad."
Parents need to be reassured that PP-FGID is one of the most common conditions
in children.
Providing education on the chronic but benign nature of the condition is
important, since parents are frequently worried and may have misconceptions. A
frequent concern is whether the child will always have abdominal pain.
Pediatricians can explain to parents that similar to asthma, the child has a
predisposition for this condition and that he/she may be prone to episodes of
abdominal pain, although these may not happen again in the near future.
Children and parents are often worried that nobody believes the symptoms or
understands what they are going through. It is essential to let the child know
that you as a doctor believe the symptoms are real. Physicians have to show
empathy and understanding, reassuring the family that the symptoms are not just
in the child's head.
It also is important to reassure parents about the adequacy of earlier
investigations by prior physicians. It helps to affirm that if the previous
doctor did not find anything with the extensive battery of tests, you too will
not find anything new by repeating or ordering any other tests. PP-FGID can be
compared to a bad migraine, in that the pain can be extreme and debilitating,
but no tests, not even brain CT scans, will provide any valuable
information.
Biopsychosocial model of care
The child with functional abdominal pain should be treated in the context of
a biopsychosocial model of care. The model proposes that this condition may
result from an interaction of multiple factors, and therefore care may also
require multiple types of treatments. Treatment should be tailored to individual
needs and cases. The nature of the condition may require a multidisciplinary and
personalized approach.
It is important to discuss the prognosis and agree on the goals of treatment.
Goals should be realistic, focused on decreasing pain and improving quality of
life. Setting the goal to abolish pain may result in failure and loss of trust
if a new episode of pain occurs. Setting unrealistic goals may lead to
disappointment even in the case of good outcomes, such as achieving a lower
degree of pain to the level that does not affect the patient's daily
function.
At the same time, the physician should explain that the resolution of the
condition will not be achieved without the cooperation of the patient and
family, and that it is very important that the patient take responsibility for
the process of healing. Patients who are currently missing school should be
encouraged to return to school. School attendance is not part of the problem and
in fact is part of the solution. Distraction from pain is a useful strategy.
While in school, children are distracted and less focused on pain or other
ailments. Adequate social interaction also facilitates healing. School re-entry
may occur in stages. To build confidence, the child may go only for 2 hours on
the first day, 4 hours on the second day, and so on. Parents should be made
aware that they might be reinforcing the symptoms by allowing the child to
obtain secondary gains, such as staying home from school.
The role of the brain-gut axis and stressors in the pathophysiology of
symptoms should be explained to the family. The physician should focus on
understanding whether any stressful situations may be present in the child's
life. These may include family distress, abnormal family dynamics, problems with
peers or in school. If present, psychological or social problems need to be
addressed.
However, proposing that anxiety or any other psychological condition might be
involved in causing the pain may result in the patient and family becoming
defensive and losing trust. If anxiety is perceived, it is useful to validate
the condition, since some degree of anxiety is expected, considering the amount
of suffering the patient is experiencing.
When anxiety impairs daily functioning, patients should be referred to a
mental health professional. Once the patient or parents agree that having pain
and missing daily activities can cause anxiety, it is usually easy to refer. If
a patient is referred to a mental health professional, contacting the specialist
in advance is frequently helpful. It is very common to receive a letter from a
specialist stating that the patient does not have a psychological condition
according to the DSM IV-R. Patients with functional abdominal pain usually do
not have a psychological condition. The goal of the mental health referral is to
help the patient cope with the condition through cognitive-behavioral
therapy.
Treatment
There is a paucity of evidence-based recommendations for most of the
medications used in the treatment of PP-FGIDs in children. Most of the
medication treatments are based on anecdotal experience or adult data.
Therefore, the physician should be judicious in prescribing medications for
PP-FGIDs. Medications should be part of a multifaceted, individualized approach
aimed at relieving symptoms and disability.
Patients with pain associated with dyspepsia may benefit from the use of
acid-reduction therapy. Although there are no pediatric data that justify their
use, the use of antispasmodic agents and smooth muscle relaxants is common.
Non-stimulating laxatives or antidiarrheals may be used for associated symptoms
(altered bowel pattern), as they do not relieve pain. Non-steroidal
anti-inflammatory drugs (NSAIDs) are not effective in treating PP-FGIDs.
A clinical trial of enteric-coated peppermint oil has shown that this herbal
therapy could be beneficial in the treatment of functional abdominal pain in
children.[16] However, enteric-coated peppermint oil is difficult to obtain in
pharmacies, expensive and not covered by insurance companies. Non-enteric coated
preparations may lead to esophagitis and mild rectal irritation.
A recent double-blind placebo-controlled trial found cyproheptadine
efficacious for the treatment of PP-FGIDs in children.[17]
Data show conflicting results about the benefit of low-dose tricyclic
antidepressants in treating PP-FGIDs in children. One double-blind
placebo-controlled study found significant improvement with amitriptyline in
adolescents with IBS. However, recently published large, randomized,
placebo-controlled multicenter studies of amitriptyline showed that it was
equally effective as placebo in children with IBS, functional dyspepsia and
functional abdominal pain.[18,19] These studies showed a very substantial
placebo effect, which underscores the importance of the physician-patient-family
relationship.
Data in adults suggests that selective serotonin reuptake inhibitor (SSRI)
antidepressants do not have any advantage over tricyclic antidepressants for
managing functional abdominal pain.[20] A clinical trial of SS RIs for children
with PP-FGIDs is underway.
Dietary interventions including fiber supplements, lactose-free diets or
lactobacillus supplementation have not been proven to be beneficial in treating
children with PP-FGIDs.[21] Parents often link the onset of symptoms with the
ingestion of dairy products. There is no evidence to support that lactose
ingestion results in worsening symptoms of PP-FGIDs.[22] Although some studies
have shown improvement in bloating and pain in response to probiotics, their
benefit in the treatment of abdominal pain is controversial.[23]
As mentioned earlier, cognitive-behavioral therapy may be a useful
intervention for children with PP-FGIDs. There also is increasing scientific
evidence for the benefit of some complementary treatments, including
hypnotherapy and guided imagery.
A 3-month clinical trial of hypnotherapy in the treatment of functional
abdominal pain in children has proven this technique to be beneficial. The study
randomized children to 6 sessions of either hypnotherapy or supportive
"traditional" medical care. Hypnotherapy was superior to the supportive medical
therapy at all times, even after discontinuation of therapy.[24]
Guided imagery with progressive muscle relaxation is a technique that uses
the patient's imagination to achieve improvement of symptoms.[25] This is a
simple, noninvasive therapy with potential benefit for treating children with
PP-FGIDs.[26-28]
However, the utilization of alternative and complementary therapies is
sometimes difficult. Some patients may be reluctant to use these therapies while
in other cases, insurance or geographical limitations may preclude their
use.
Conclusion
PP-FGIDs continue to be challenging medical conditions for the patient,
family and physician alike. The biopsychosocial model provides the conceptual
basis for the understanding of FGIDs. Accordingly, a comprehensive tailored
treatment plan can be offered to the patient and the family. Parents are often
confused about the exact pathogenesis of FGIDs. Effective explanation of the
various theories will help to educate parents about these conditions and
alleviate their anxiety.
References
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