A 15-year-old Girl with Chronic Abdominal Pain

Pediatric Pathways

A 15-year-old Girl with Chronic Abdominal Pain

After reading this article and answering the review questions the reader will be able to:

  1. Define functional abdominal pain
  2. Explain the importance of the history and physical exam (rather than extensive investigation) as paramount in the diagnosis of functional abdominal pain
  3. Explain the proposed etiology of functional abdominal pain to a patient and parent

Case

Tami is a 15-year-old girl who presents in November to your pediatric GI clinic with the complaint that “her stomach always hurts.” She is accompanied by her parents, who inform you that she is fasting, in case you wanted to perform an endoscopy. The pain has been present for the past 10 months, is somewhat better during the summer and does not wake her from sleep. It is described as constant, dull and occasionally crampy, primarily around the umbilicus. There is no association with meals, bowel movements or exercise. She has missed school on six separate occasions this fall and been seen for the pain by her primary care doctor repeatedly and on two occasions in her local ED. Trials of proton pump inhibitors, a stool softener, lactose exclusion and high-fiber diets have not helped.

She has a history of occasional headaches and nausea. No weight loss, mouth ulcers, diarrhea or fever. She has regular menses. She achieves good grades in school, plays soccer, and has not missed games or practices. She denies stressors or negative life events. Family history is significant for migraines but no GI diseases.

Her growth chart and physical exam are normal. Specifically, there is no evidence of abdominal fullness, tenderness or perianal abnormalities. She has had repeated normal workups including CBC, CRP, Lipase and liver enzymes along with a normal U/A and pregnancy test. ED visits prompted both a CT and ultrasound of her abdomen, both of which were normal.

The patient and parents’ main concern now is if we are missing something and whether she should try a gluten-free diet.

Definitions and Terminology

Chronic abdominal pain is a common complaint in children. It rarely has an identifiable organic cause but rather is thought to be a functional disorder. The phrase “recurrent abdominal pain (RAP)” has been used since the publication of the seminal article on abdominal pain in children by Apley and Naish in 1958. Most subsequent studies of RAP over the next three decades used their criteria of three or more episodes of pain over three months severe enough to affect the child’s activities. Over time, these entry criteria became a definition and the term recurrent abdominal pain became a synonym for functional abdominal pain (FAP).

The criteria proposed by Apley and Naish in their early papers have been criticized for their ambiguity and for including both organic and nonorganic causes. Recently a subcommittee on chronic abdominal pain from the American Academy of Pediatrics (AAP) and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) issued clinical and technical reports on chronic abdominal pain recommending abandoning the term recurrent abdominal pain in favor of the term functional gastrointestinal disorder (FGID). The latter phenomenon can be further categorized as functional dyspepsia, irritable bowel symptom, abdominal migraine or functional abdominal pain (see Table 1 online). These terms are defined in the Rome III criteria, a consensus statement proposed by adult and pediatric experts in functional gastrointestinal disorders.

Table 1. Rome III criteria: The Functional Gastrointestinal Disorders (FGIDs)

Functional disorders: children and adolescents

  1. Vomiting and aerophagia
  2. Abdominal pain-related FGIDs
    1. Functional dyspepsia
    2. Irritable bowel syndrome
    3. Abdominal migraine
    4. Childhood functional abdominal pain
  3. Constipation and Incontinence

Impact of Chronic Abdominal Pain in Children

The prevalence of functional gastrointestinal disorders in children varies depending on study inclusion criteria, but reports indicate that 9% to 25% of children suffer from chronic abdominal pain at some time during childhood. FGIDs account for 2% to 4% of visits to general pediatric practices and more than half of encounters in pediatric gastroenterology clinics. There is a seasonal variation of presentation of FAP to the pediatric gastroenterologist: more children are seen in the winter months compared to the summer. The quality of life in children with FAP is worse than it is in the general population and even worse than it is in those who suffer from migraines or asthma. Children with FAP are more likely to have functional impairment, psychiatric symptoms and somatic pain complaints than are controls at five-year follow-up and data suggest this difference continues into adulthood. Little is known about the cost of FGIDs in children, but adults with irritable bowel syndrome (IBS) use 50% more health care resources than do controls. The total direct and indirect costs in adults with IBS are more than $20 billion per year in the United States. In a study from a pediatric GI division in a tertiary children’s hospital in Illinois from 2007, the mean cost of workup for a child with FAP was estimated to be $6100, which is 77% of the annual per capita health care expenditure for that year. In addition, there are hidden costs including travel, babysitting and parental work absence associated with FAP.

Etiology of Functional Abdominal Pain

Despite the high prevalence of FAP, there is surprisingly little research available and our understanding of its etiology remains poor. This makes it difficult to define and explain to our patients and their parents. After Apley and others showed that fewer than 10% of children with RAP had an organic inflammatory, anatomical, metabolic, infectious or neoplastic etiology of their pain, the focus shifted to investigating psychological and motility-related causes. The implication in Apley’s work that psychological abnormalities may cause RAP likely did a disservice to patients, in that it may have led physicians to question the true severity of their patients’ pain. If no organic disease was present, RAP became an endpoint diagnosis and often families were told that nothing was wrong with the child.

While the evidence available shows that children with FAP and their parents are more likely to have depression and anxiety than are healthy controls, children with chronic abdominal pain of explained organic nature also are more likely to be depressed and anxious. Thus, the presence of a psychiatric diagnosis is not helpful in distinguishing between FAP and other causes of pain, nor does it have a prognostic value. Psychological factors may influence parents to bring children to health care providers but should not be considered a sole etiology of FAP. Sophisticated studies have also failed to identify abnormalities in motility as a cause for the pain in children with FAP.

In the last two decades, more experts believe that the pathophysiology of FAP involves abnormalities and dysregulation in the enteric nervous system (ENS), a network of nerves involving the entire digestive tract. The ENS is often referred to as the gut brain or the little brain in the gut; it communicates bidirectionally with the central nervous system (CNS). There is growing evidence that visceral hyperalgesia plays a role in FAP. Visceral hyperalgesia is explained as an abnormally low threshold of pain sensation in the digestive tract, in which physiological stimuli that would otherwise be ignored are interpreted as pain. These stimuli may include meals, bowel distention, hormonal changes or psychological stress, such as anxiety and separation.

Inflammatory processes including infection or allergy at the mucosal level may play a role in hypersensitizing ENS afferent nerves. Infection has been shown to trigger visceral hyperalgesia that persists even after the offending agent is cleared. Recently the microbiome of the gut has been of increased interest. A microbiome is the totality of microbes, their genetic elements (genomes) and environmental interactions in a particular environment. The microbiome influences gene expression and inflammation in the gut and is affected by diet and the use of antibiotics. There is evidence that the microbiome in children and adults with IBS differs from that in healthy controls. The processing of afferent messages in the CNS also affects the perception of pain, as seen in brain imaging studies in adults with IBS and influenced by negative life events. The concept of hyperalgesia is helpful in explaining FAP to patients and parents by using analogies to other more tangible examples. One way of explaining this is an analogy to burn scars, in which the affected skin is hypersensitive to cold and heat even after the wound appears to be completely healed.

Workup

The AAP NASPGHAN subcommittee on chronic abdominal pain recently concluded that FAP can be diagnosed without additional testing as long as (1) the physical exam is normal, (2) there are no alarming symptoms in the history (Table 2), and (3) stools are negative for occult blood. It is worth mentioning that studies have shown minimal yield of pH probes, endoscopies, CT scans or ultrasounds in children with chronic abdominal pain.

Table 2. Alarming Symptoms, Signs and Features in Children and Adolescents with Noncyclic Abdominal Pain-Related Functional Gastrointestinal Disorders

  • Persistent right upper- or right lower-quadrant pain
  • Pain that wakes the child from sleep
  • Dysphagia
  • Arthritis
  • Persistent vomiting
  • Perirectal disease
  • Gastrointestinal blood loss
  • Involuntary weight loss
  • Nocturnal diarrhea
  • Deceleration of linear growth
  • Family history of inflammatory bowel, celiac or peptic ulcer disease
  • Delayed puberty
  • Unexplained fever
  • Oral ulcers

However, the committee also stated that testing might be performed to reassure the patient, parent and physician, particularly if the symptoms significantly impact the patient’s quality of life. This seems to be the approach taken by many primary clinicians and even more so by pediatric gastroenterologists, with significant cost. In our practice at AFCH we usually obtain a complete blood count, check for inflammatory markers including C-reactive protein and screen for celiac disease.

Treatment and Conclusions

Unfortunately, few studies exist on the treatment of children with FAP. The subcommittee found inconclusive evidence regarding the efficacy of some common practices, including increasing fiber or excluding lactose in the diet. Antidepressants are sometimes used, but the evidence of efficacy for treating abdominal pain is inconclusive and conflicting. One randomized study using amitriptyline and placebo showed that both were effective in reducing pain in children with FAP. Interestingly, an adult study showed that placebo without deception was effective in IBS. In children there is evidence that self-guided imagery and hypnotherapy are useful treatments, and a Cochrane review of the pediatric literature concluded that cognitive behavioral therapy was useful in children with FAP. There is also evidence that peppermint might help children with IBS. Recent focus on the microbiome and its role in the gut has raised the question of whether changing the composition of the microbes in the gut with diet, antibiotics and/or probiotics might help individuals with functional abdominal disorders.

Education about FAP along with reassurance for the family and child is paramount, along with setting appropriate goals for increasing daily functioning. It is also important to defuse the notion that an underlying organic cause has been missed, while reassuring families that you take their concerns seriously. Perhaps most important, we must emphasize that, despite the lack of a discernable organic etiology, we still believe that the pain is real. We should counsel that the pain is unlikely to resolve completely or immediately but that we will help the family with strategies to decrease symptoms, ideally using cognitive behavioral therapy, and to cope with the pain that persists.

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References

  1. Nurko S, Di Lorenzo C. Functional abdominal pain: time to get together and move forward. J Pediatr Gastroenterol Nutr. 2008;47(5):679-80.
  2. Di Lorenzo C, Colletti RB, Lehmann HP, et al. AAP Subcommittee; NASPGHAN Committee on Chronic Abdominal Pain. Chronic abdominal pain in children: a technical report of the American Academy of Pediatrics and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr. 2005;40(3):249-61.
  3. American Academy of Pediatrics Subcommittee on Chronic Abdominal Pain; North American Society for Pediatric Gastroenterology Hepatology, and Nutrition. Chronic abdominal pain in children. Pediatrics. 2005;115(3):e370-81.
  4. Rasquin A, Di Lorenzo C, Forbes D, et al. Childhood functional gastrointestinal disorders: child/adolescent. Gastroenterology. 2006;130(5):1527-37.
  5. Dhroove G, Chogle A, Saps M. A million-dollar work-up for abdominal pain: is it worth it? J Pediatr Gastroenterol Nutr. 2010;51(5):579-83.
  6. Camilleri M, Di Lorenzo C. Brain-gut axis: from basic understanding to treatment of IBS and related disorders. J Pediatr Gastroenterol Nutr. 2012;54(4):446-53.

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