Recurrent Abdominal Pain in Children

Apley, a Bristol paediatrician, and Naish defined recurrent abdominal pain (RAP) in 1958 as abdominal pain that:

• Waxes and wanes
• Occurs with 3 episodes within a 3 month period of time
• Is severe enough to affect a child's activities

It is of significance because:

• It is one of the most common symptoms in childhood worldwide.
• It is responsible for considerable morbidity, missed school days and high use of health resources.
• It is made up of functional disorders (those which cannot be explained by structural or biochemical disorders) and organic disorders. Apley recorded that only 8% of patients with RAP had, after extensive investigation, any organic pathology.¹
• Diagnostic uncertainty, chronicity and increasing parental anxiety often follow the unremitting and disruptive course of the condition. This can make management by GPs and paediatricians very difficult, time consuming and expensive.

There are problems with the definition of RAP and it has been criticised over the years, often because it includes both organic and functional conditions. RAP was defined and identified because it was recognised that it was very common, very disruptive to families and most often not accompanied by easily definable organic pathology. However the heterogeneous composition of the population with a condition comprising both organic and functional disorders reflects the clinical challenge of diagnosis, the difficulties with the definition of RAP and difficulties with management of RAP. It is worth considering the attempts to improve on Apley's original definition.

• Recurrent abdominal pain is a common symptom in children. It occurs in as many as 10% of children.
• An organic cause is found in few of these patients. However differences in prevalence of organic disease are found depending on the population studied and the criteria used. It may be as low as 5% in the general population and as high as 40% in paediatric gastroenterology outpatients.
• It is still the case that the paucity of organic pathology in these patients has led to the conclusion that psychological factors are important. However this is not always reflected in the results of studies which do not always demonstrate differences in emotional and behavioral scores in the patients with organic pathology and those without.⁵
• It occurs most commonly between age 4 and 14 years. Some studies show within this age range peaks in incidence at 4-6 years and 7-12 years.²
• Girls are probably affected more often than boys.
• Incidence appears similar in different socioeconomic groups although low socioeconomic status is cited as a factor increasing incidence by some.²
• Recently an association between obesity and recurrent abdominal pain has been reported.⁶ Diet may also play a part. A recent study reported an inverse correlation between fruit consumption and recurrent abdominal pain.⁶ It is apparent that many factors are involved consistent with the concept of a biopsychosocial model for illness.²

• Sexual abuse. Little is known about the association with sexual abuse, but studies do confirm that the duration of symptoms is longer in children who were victims of sexual abuse.²
• Parental anxiety in the first year of life is associated with chronic abdominal pain before age 6 years. This may be because the anxiety prompts a response which strengthens recurrence of pain.²
• Family factors are important and children with a parent with gastrointestinal problems are more likely to have RAP.
• From the published studies it seems that the causes of RAP are multifactorial. A biopsychosocial model has been proposed which proposes a concept which acknowledges a complex interplay between many different factors. This is useful when considering management (ranging from behavioral treatments to pharmacological ones) and when explaining the condition to parents and children.

History

A good history is traditionally the cornerstone of diagnosis. This is illustrated in a paper looking analytically at the history in diagnosis.⁷ Attempts have been made to improve diagnosis of functional bowel disorders using the Rome classification system.^8,9 Refinement of this approach as a diagnostic tool is called for as it looks very promising.¹⁰ Subgroups or diagnoses within the group with RAP (such as functional constipation and abdominal migraine) can be identified using these diagnostic tools.⁹ It is not yet possible to define a questionnaire or diagnostic tool but the attempts are interesting and enlightening. Ultimately they may yield a helpful diagnostic questionnaire, but at the moment there is no substitute for a careful and thorough history.

• The history should include an analysis of the pain.
  • Site of pain.
  • Quality and nature of pain.
  • Information on the timing and duration of pain.
  • Whether pain is relieved by defaecation or not.
  • It is particularly important to ask about any associations with the pain and particularly the effect on daily living.¹¹
• The history should encompass inquiry about:
  • Gastrointestinal symptoms including bowel habit.
  • Genitourinary symptoms.
  • Family history. This is particularly important in recurrent abdominal pain. There may be a history of illness in siblings.¹² There is an association with family history of depression.¹³ A family history of recurrent abdominal pain is very likely (if positive the incidence of recurrent abdominal pain in the children is 6 times greater). Migraine, peptic ulcer, depression, appendectomy and convulsions are also more common in the families of children with recurrent abdominal pain.
  • Past medical history. It is important to review any past illnesses, hospital admissions, relevant perinatal and neonatal history.

Examination

There is no good data evaluating the diagnostic value of physical examination.² However careful and thorough examination is generally recommended, particularly when first seen. Typically there may be vague tenderness but no guarding or rigidity. It can be reassuring to parents to see that this is done and to discuss findings, including the reassurance of normal findings. Examination should include at least the following:

• Height and weight
• General examination
• Abdominal examination

Discriminating between organic and functional causes of RAP

The traditional view

• Typically paediatric textbooks emphasise that children presenting with recurrent abdominal pain are unlikely to have organic disease. Diagnostic triage is entirely appropriate in primary health care.
• It is acknowledged that the diagnosis can sometimes be difficult but that in practice discriminating organic from functional disorders is achieved with a good history backed by knowledge and experience but without protracted examinations and investigations. Simple tests such as urine testing are usually all that is required.
• The history helps to exclude organic causes and identifies important factors which may be triggering the pain.
• The diagnostic process may be followed also in part to reassure parents. However it can be difficult to reassure parents when the pain continues and diagnostic uncertainty exists.

Recent perspectives²

Whilst there is acceptance of the traditional approach it should be remembered that:

• There is a long list of possible causes for recurrent abdominal pain. It is not possible to categorically exclude them all with definitive testing or investigation.
• The distinction between so called organic disease, functional disorders and emotional factors can be difficult. Frequently there is overlap between physical and emotional illness and the two may coexist.
• The history in children can be difficult. There may be difficulties describing the pain and localising it once the pain has passed. The child's vocabulary may limit description but there may also be emotional and psychological barriers to the process of history taking.

It is perhaps not surprising that a committee of American paediatric gastroenterologists recently concluded that there were no diagnostic tools to distinguish functional from organic abdominal pain.² They recommend further diagnostic testing only in children with alarm symptoms or signs such as those outlined in the table above. They do not give an exhaustive list of what constitute alarm symptoms. They also recommend abandoning the term 'recurrent abdominal pain'.

The list of possible causes is long but the list of probable causes is shorter.

Investigations may be required to exclude particular conditions suggested by the history and examination. It is useful to pursue further diagnostic testing only in the presence of alarm symptoms.² Such tests include comprehensive metabolic screening, stool analysis, inflammatory markers and other laboratory tests. These help identify conditions such as inflammatory bowel disease and coeliac disease. Extensive investigations are not usually indicated or helpful. No studies have evaluated the usefulness of common laboratory tests.² These basic tests are often recommended:

• Full blood count
• ESR
• Urinalysis and microscopy
• Stool examination for parasites
• Plain abdominal X-ray

Many tests may be done selectively, but it is worth considering that many tests when studied do not discriminate between functional and organic pain. As such they should not be used in an attempt to 'screen' for organic disease. Further tests which may be used include:

• Abdominal ultrasound
• Endoscopy
• Testing for helicobacter pylori
• Antiendomysial antibodies

In fact studies show positive results for each of these tests equally in control groups and in the patients with chronic abdominal pain.²

There are associations with migraine, IBS, psychiatric disorders (anxiety, depression).¹³

Recurrent abdominal pain will require follow up and may need referral. It cannot be dealt with in a single consultation.
Most children with RAP have mild symptoms which are successfully managed in primary care.² A detailed plan of management will depend on diagnosis. It is likely that a significant part of management will involve discussion, explanation and reassurance. A specific treatment or intervention cannot be recommended because none has yet been identified.²A summary of these is as follows:²

• Beneficial treatments include:
  • Cognitive behavioral therapy (CBT). Studies show clear beneficial effects for RAP.
  • Family therapy. Often part of CBT approach and effective.
  • Peppermint oil. Studies show benefit for IBS.
  • Pizotifen. This appears to be beneficial for abdominal migraine (Rome II criteria).
• Inconclusive or unhelpful treatments include:
  • Famotidine for RAP and dyspepsia.
  • Additional dietary fibre for RAP.
  • Lactose-free diet for RAP.
  • Lactobacillus GG for RAP.

• Many of the studies on prognosis relate to hospital practice not primary care.²
• It is generally more likely that children with recurrent abdominal pain will develop chronic abdominal symptoms in adulthood and as many as 30% may continue thus.²
• Many will continue to suffer from irritable bowel syndrome.^1,14,15,5
• There is evidence that children with chronic abdominal pain are more likely to have emotional and psychiatric disorders later in life.²
• Generally speaking however follow up studies show that parental factors rather than the psychological characteristics of the child are more important when predicting persistence of abdominal pain.²
• Possible risk factors for chronicity:
  • Age may be a factor although studies are inconclusive. Presentation under age 6 has been reported as a risk factor.
  • History of more than 6 months before presentation.
  • Family history of emotional factors. There is evidence that parental functional problems, stressful life events and sexual abuse are all associated with persistence of functional abdominal pain.
  • Anxiety, depression and severity of pain have not been linked to persistence of functional abdominal pain.
  • Eating and sleeping problems, phobias, nocturnal enuresis and other such factors have been cited. These may reflect emotional factors within the family.
• Acceptance by parents of the role of psychological factors in the maintenance of symptoms is strongly associated with recovery.