Functional abdominal pain (FAP) is a term that encompasses a number of conditions defined within the Rome IV criteria: irritable bowel syndrome, functional dyspepsia, abdominal migraine and functional abdominal pain not otherwise specified.[1]  FAP is estimated to occur in 3-16% of the population depending on country of presentation, gender and age. 

Diagnosis is challenging and relies on a thorough patient history, exclusion of other organic causes, whilst trying to minimise invasive testing, which may add further anxiety to the patient, carer and family. All FAP-NOS patients will report that symptoms can have a severe impact on quality of life, which is demonstrated by a higher incidence of anxiety and depression and increased access to healthcare.

Management of FAP not otherwise specified (FAP-NOS) in children is focused on a multidisciplinary approach including dietary manipulation, gut–brain psychotherapies, pharmacological treatments, probiotics and percutaneous electrical nerve field stimulation. A large proportion of children with FAP-NOS will continue to have symptoms into adolescence and on into adulthood.[2]  In view of the potential of life-long symptoms with a negative impact on quality of life, it is essential that treatment is targeted at an early age and patients, families and carers are equipped with strategies to try to minimise the negative impact of symptoms.

J is a 15-year-old female referred to paediatric dietetics because of ongoing abdominal pain and to see if dietary exclusions may help. J is one year post-menarche and reports her periods are regular. Abdominal pain is reported to be a daily problem and scores 8/10 at its peak. The pain is described as a dull ache and is present most of the time. J reports the pain doesn’t wake her overnight, but at times she can struggle to get to sleep because of the pain.  J has tried hot water bottles, peppermint tea and painkillers without any significant relief. 

J has stopped attending school for the past four months – she reports that her abdominal pain makes it difficult to concentrate. J is attempting to study at home as she has exams next year which she understands to be important. 

There are no growth concerns. J reports she opens her bowels regularly and consistency is normal. J has had extensive investigations under paediatrics prior to referral. all investigations have come back within normal limits, and the diagnosis of functional abdominal pain not otherwise specified has been made. 

J and her parents asked for a referral to the dietitian, as she is keen to see if making changes to her diet may be beneficial in reducing symptoms.

There is some evidence that would suggest that patients like J would benefit from a trial of a low-FODMAP diet (low fermentable, oligosaccharides, disaccharides, monosaccharides and polyols). However, evidence within the paediatric setting is limited. 

Rexwinkel et al evaluated the efficacy of a low FODMAP diet in adolescents with IBS and FAP-NOS.[3] They carried out a multicentre trial and included patients aged 12-18 years. They provided patients with low-FODMAP information; however, no dietitian was involved in supporting the young people or families. There were 325 patients included, of which 81 (24.9%) reported a 30% reduction of abdominal pain after four weeks (29.3% IBS group, 18.8% FAP-NOS group). They concluded that the evidence presented did not make FODMAP a first treatment option for patients.[3]  

Van Tilburg & Felix looked at exclusion diets, as well as the role of probiotics within this patient group.[4] Although this evidence is now 12 years old, many aspects of what they discussed remain relevant today. They concluded that many children and young people with IBS and FAP will experience symptoms post-eating. However, more work needs to be done to look at the exact role that food plays in FAP/IBS patients. Many of the studies presented at this time were of low quality and had small sample sizes, and this made it difficult for conclusions to be drawn from them.   

While considering dietary exclusions, it is important as dietitians to look at the overall dietary intake prior to removing any foods from the diet. We should ensure that patients are eating regularly, that they are eating both soluble and insoluble fibre and have an adequate fibre intake, that they are not having excessive intake of high sugar, high fat or caffeinated foods or drinks. We should also ensure that meals are not being eaten too quickly, and the young person is not air swallowing.

J had an irregular meal pattern: she often missed breakfast, ate convenience high-fat foods at mid-morning time and skipped lunch for a can of caffeinated drink. J’s diet was low in fibre, and she reported often not feeling like eating due to the pain. We discussed the importance of a balanced diet using the Eat Well Plate to provide education; we discussed the benefits of a structured meal plan, eating little and often when she felt unable to eat bigger meals, and reducing her intake of fizzy drinks. J agreed to make these changes initially before any dietary eliminations. 

When J returned to clinic after three months for review, she reported that the pain was marginally better, still occurring most days, but reduction in scoring to 6/10. She remained unable to attend school but was in discussions with the school around a phased return. She had also managed to reengage her friendships and was starting to meet friends. 

We discussed the current dietary intake and the changes that J had made. She remained keen to trial a low-FODMAP diet, as she had read that it had helped similar patients and was keen to see if her symptoms could be improved further. We discussed the evidence base and that the evidence in paediatrics was low. However, there is a stronger evidence base in the adult setting. 

We discussed the challenges faced with such a restrictive diet and how J would manage these. J decided to attempt a low-FODMAP diet and we spent time explaining the foods J could have and the foods she should avoid. We discussed the length of time the diet would be followed and the reintroduction of foods to ensure her diet is not overly restrictive.

J was seen in clinic four months later. She had attempted a low-FODMAP but felt it hadn’t made a significant impact on her symptoms enough to continue it. She was now eating an unrestricted diet but following the advice around meal structure that had been provided in the first consultation. J and her parents had self-funded a cognitive behavioural therapy course, which she felt had provided her with strategies and mindfulness techniques, which she felt she had found beneficial. She had also been able to reduce her pain medication.