IBS is common in childhood and adolescence and affects up to 10–20 % of adolescents, and it is similar to the adult presentation [10]. The typical features include abdominal discomfort or pain with two of three additional features; pain relieved with defecation, onset of pain associated with a change in form or frequency of stool (Table 19.2). Other supportive symptoms include—abnormal stool frequency or type, passage of mucus and bloating/distension. There is no evidence of an underlying organic disorder to explain the symptoms. There may well be a description of exacerbation of symptoms with stressors (physical/psychological), for example with exams/performances. IBS can coexist with organic disease and is common in conditions such as inflammatory colitis. A family history of IBS is common and can help parents understand their child’s symptomatology and help with reassurance and explanation that there is no serious underlying organic disease.

Care should be taken in asking families about change in stool frequency/form. A total of 118 children, aged 7–10 years, with RAP , were surveyed to compare parental and children’s symptom recall to symptom diaries over a 2-week period, and also to the Rome III description of IBS. There was relatively poor correlation between symptom diaries and parental symptom recall, and the authors speculated that when completing questionnaires asking about pain–stool relations, parents compared their child’s symptoms to perceived norms of pain and stooling, rather than looking at their child’s symptoms over at least 25 % of the time. Children often had difficulty putting their symptoms into a pattern, so had difficulty recognizing their symptoms as IBS. Parents sometimes did not recognize their recorded symptoms as suggestive of IBS, due to recall bias, and infrequent events affected their interpretation of their child’s symptoms; symptom diaries can improve parental understanding and acceptance [9] .

It is important to recognize this phenotype. Abdominal migraine is a distinct clinical entity, distinguished by paroxysmal episodes of intense, acute peri-umbilical pain that lasts for one or more hours. These painful episodes can be associated with nausea and vomiting, pallor, headache, anorexia, and photophobia (Table 19.3). It is characteristic of migraine that the child is completely well between episodes. It is important to recognize that children may have cyclic vomiting as the main manifestation. Cyclic vomiting syndrome plus refers to cyclic vomiting in children with underlying neurological problems .

There are potential specific treatments for abdominal migraine/cyclic vomiting, as discussed below.

It is likely that abdominal migraine , cyclic vomiting syndrome and migraine headache are different clinical presentations of the same disorder along a disease spectrum. Many patients have a history of travel sickness. Dietary triggers include caffeine-, nitrite- and amine-containing foods. The diagnosis of abdominal migraine is supported by a positive family history of migraine headache.

FAP encompasses episodic or continuous abdominal pain in a school-aged child , with insufficient criteria for other functional GI disorders as described above (Table 19.4). There is generally no relationship with physiological events (e.g. eating/defecation), and pain is localized to the umbilicus. There is at least some loss of daily functioning, and the pain is not feigned. There is no structural/metabolic abnormality that would explain the abdominal pain.

Functional abdominal pain syndrome refers to the above, occurring > 25 % of the time, with additional somatic symptoms, for example headache, limb pain, sleep disturbance and chronic fatigue and hence the term syndrome. This group tends to be more complex to treat and to do less well. The presence of features such as limb pain and chronic fatigue can be predictive of symptom perseverance [11, 12].

FAP can coexist with organic disease and like other functional GI disorders can occur in children with significant organic disease such as cystic fibrosis and inflammatory bowel disease (IBD) [13]. It is important that parents become aware of this, and that clinicians are aware and avoid overtreatment and that such factors are considered in the assessment of children with serious underlying chronic disorders.

The group of children with FAP syndrome is often the most difficult to manage.

In summary

Understanding the etiopathogenesis is essential, to provide parents with a clear explanation, that they can understand, and that helps address their concerns . Recurrent (functional) abdominal pain appears to be a variable combination of genetic predisposition, personality, visceral hypersensitivity and considering predisposing triggers (physical and psychological) is key. The acceptance of the biopsychosocial model by the patients and their families is an important factor in predicting a positive outcome and can help address some of the family’s understanding of the role of pain and coexistence with anxiety.

Normally, the contraction of the GI tract follows two patterns: rhythmic phasic contractions (continuously) and giant migrating contractions (several times a day). These peristaltic mechanisms should not generally cause pain. In patients with FAP, increased levels of substance P and other nociceptive transmitters lower the threshold for the child’s perception of pain [28]. Adult models have demonstrated increased concentration of nociceptive transmitters, and neuronal hypersensitivity at the mucosal, spinal and cerebral levels, causing visceral hypersensitivity and intestinal dysmotility [28]. The presence of physical and psychological stressors exacerbate this ‘visceral’ hypersensitivity, and conversely effective stressor control through appropriate parental understanding, reassurance and distraction downregulates the production of these nociceptive neurotransmitters [29]. This reduces the perception of these normal peristaltic waves as painful (see Fig. 19.1).

A simpler explanation more suitable for younger children is that of ‘butterflies in the tummy’ is triggered by stressful events such as an exam or big performance, but some children have got into a cycle where they are on the more extreme end of this spectrum, and their abdominal discomfort is severe, and impacting adversely on their functioning, but that this does not indicate serious underlying organic disease. Addressing underlying stressful triggers is important for symptom improvement.

For abdominal migraine , although similar underlying themes emerge, the coexistence with headaches has led researchers to look at vascular instability and mast cells. In migraine, which is more common in those with atopic diseases, there is evidence for the perivascular aggregation of mast cells. Secretion of nociceptive transmitters such as substance P and calcitonin gene-related peptides cause mast cells to release proinflammatory, vasoactive and neurosensitizing peptides, causing the vascular instability and visceral hypersensitivity seen in migraine and abdominal migraine. This is exacerbated by higher levels of corticotrophin-releasing hormone (elevated by stress), which also elevates interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) [31]. This could potentially explain the therapeutic effect of pizotifen, a histamine antagonist in mediating mast cell action, or the frequently tried ‘migraine diet’, although many patients do not respond significantly to these measures, and understanding stressors, using the biopsychosocial model outlined above, may well be the more effective management strategy [31]. In those few patients who suffer significantly with cyclic vomiting syndrome , some benefit from early intervention including intravenous fluids and antiemetics such as ondansetron, to reduce the effects from vascular instability potentiated by dehydration. Further details are available in Chap. 25.

This is the cornerstone of the patient journey, to exclude organic disease and identify key features to make a convincing diagnosis. A full history and examination aims to exclude organic pathology and, if no concerning features of disease are found (Table 19.5), a targeted set of investigations should be initiated, that should be one-stop, rather than multiple and consequent investigations which may increase family anxiety and exacerbate symptoms should be avoided unless clinically indicated. Red flags may still be present in functional conditions, but should lower the threshold for further investigation.