Chronic "Functional" Abdominal Pain in Children - November 2006
Abdominal pain (AP) as a symptom is highly prevalent in the pediatric population. Up to 20% of children in middle and high school will report abdominal pain at some time; 50% of children with abdominal pain miss school and the societal cost is estimated at $25 billion dollars a year in both direct and indirect costs. In adults, these patients are bundled under the term Irritable Bowel Syndrome (IBS). IBS has a worldwide prevalence between 4% - 30% and accounts for 28% of visits to an adult GI specialist. We must note, this term is inappropriate for children at this time, yet as with the definition of functional, this is a moving target.
There are over 800 different diseases that can present with abdominal pain as an initial symptom. Some of these conditions can be serious, striking fear into the heart of the general practitioner and the patient’s family alike. This fear leads to invasive testing, usually with negative results. Parental reporting regarding the severity of symptoms usually overstates the actual functional limitation symptoms set on the child. Eventually, it becomes clear that the child might have a non-organic disorder. The terms ‘Functional Abdominal Pain’ (FAP) and ‘Recurrent Abdominal Pain’ (RAP) are used interchangeably to describe these syndromes, yet this isn’t appropriate either! So what can we do?
Pathogenesis and Classification
All neurotransmitters, sensory-motor functions and receptors found in the central nervous system can also be found in the intestine. There is a predisposition for “visceral” hypersensitivity in patients identified as having FAP. Recent research has suggested several possible etiologies for this visceral hypersensitivity, including: a) over-stimulation of the enteric nervous system due to intestinal dismotility; or b) nerve ending irritation due to sub-clinical inflammatory changes within the intestinal wall.
In adults, up to 20% of patients with infectious gastroenteritis will develop IBS symptoms. Indeed, recent research into pediatric FAP and adult IBS has shown some improvement in symptoms with anti-inflammatory or antibiotic therapy. Whether infantile colic is a form of FAP is unclear. Recent epidemiologic studies have suggested that colic and gastric suctioning in the newborn period are associated with FAP in later years.
In an effort to better tailor therapeutic interventions, a group of GI specialists met to create a diagnostic classification for non-organic abdominal pain syndromes. Their efforts led to the “Rome criteria,” now in its third incarnation. This criteria classifies RAP as AP clearly associated with perturbation in defecation or fecal retention. Post-prandial cramping, diffuse peri-umbilical pain, exacerbation with exercise and improvement with defecation are all characteristics of RAP. Functional bowel disorders are subdivided into 13 different subtypes. A look at the Rome criteria is recommended for further discussion of these subtypes.
Functional vs. Organic: How Can We Tell the Difference?
Negative laboratory testing can be helpful and reassuring but is not always 100% reliable. Standard baseline evaluation should include a urinalysis, complete blood count, sedimentation rate, liver panel and lipase level (pregnancy test in the appropriate setting). Clinical criteria can help to differentiate between FAP and organic AP. Diarrhea can be present but will be intermittent and not associated with weight loss, electrolyte or serum albumin abnormalities. Often, the family will overstate the severity of symptoms leading to parental quality-of-life reporting below that of patients with Crohn’s disease. Fecal retention is a predominant feature in about 25% of patients coming to specialty care. In most cases, a simple abdominal x-ray leads to the correct diagnosis when abundant stool is noted in at least three quadrants of the colonic margin.
Poor sleep due to pain, early-morning pain with emesis, bilious emesis, blood in stool, focal complaints, poor weight gain or weight loss and extra-intestinal complaints are all signs of a potential organic etiology warranting further work-up.
Therapy
Therapeutic interventions that might be recommended based on current available evidence are: daily stool softening therapy using a non-stimulant laxative [Milk of Mg, polyethylene-glycol powder (Miralax, Glycolax)] and a fixed toileting regimen. This should be sustained for several months even if successful early-on. Adding probiotic products in the patient’s care might be of use but clear data on this issue is lacking. The use of psychopharmacology (antidepressants, anxiolytics) in the management of these disorders requires specialized care. A referral to a Pediatric Gastroenterology Center with expertise in the care of patients with these disorders is important.
Education and Monitoring
For most of these patients adequate bowel habits, avoidance of triggering foods and carbonated or caffeinated beverages is recommended. Alternative interventions like hypnosis, acupuncture, guided imagery and biofeedback can help alleviate most of the symptoms and help reach a full return to function. The important thing when faced with a child with chronic intractable abdominal pain and no clear cause is: Don’t just do something, STAND THERE. Thinking about it could save you a lot of trouble.
Recommended Reading
1) Hyams JS, Burke G, Davis PM, Rzepski B, Andrulonis PA. Abdominal pain and irritable bowel syndrome in adolescents: a community based study. J Pediatr 1996 Aug, 129: 220-226.
2) Rasquin A, DiLorenzo C, Forbes D, Guiraldes, Hyams J, Staiano, A, Walker LS. Childhood functional gastrointestinal disorders. Gastroenterology 2006; 130: 1527-1537.
3) Youssef NN, Murphy TG, Langseder AL, Rosh JR. Quality of life for children with functional abdominal pain: a comparison study of patients’ and parents’ perceptions. Pediatrics 2006 Jan; 117: 54-59.
4) Savino P, Castagno E, Bretto R, Brondello C, Palumeri E, Oggero R. A prospective 10 –year study on children who had severe infantile colic. Acta Paediatr Suppl. 2005 Oct; 94: 129-132.
This information provided by J. Antonio Quiros, M.D., Pediatric Gastroenterology & Nutrition Program, California Pacific Medical Center Department of Pediatrics.