In 1991, 1 year after the certifying examination in pediatric gastroenterology was first offered by the American Board of Pediatrics, the co-editors of Pediatric Gastrointestinal Disease wrote in their preface to the first edition of this comprehensive treatise on pediatric gastrointestinal, nutritional and hepatic disorders, "Over the last two decades, the field of pediatric gastrointestinal disease has developed from an obscure subspecialty to an essential component of every major academic pediatric program throughout the world."1
In the early years of pediatric gastroenterology as a defined subspecialty, our knowledge of important clinical problems was essentially descriptive, and many of our patterns of practice as pediatric gastroenterologists were learned from our adult gastroenterology colleagues, applying similar principles of diagnosis and treatment. The past 3 decades, and certainly the ensuing 15 years since the above text was published, have witnessed a literally logarithmic expansion in our knowledge of the pathophysiology and epidemiology of these important childhood disorders. Our approach to disease management must now not only consider biochemical and physiological principles but also must be based upon an understanding of the genetic factors underlying these diseases, to identify at-risk populations, counsel families, and improve clinical outcomes.
For the primary care provider, gastrointestinal complaints comprise important factors leading to pediatric healthcare visits. In older children, as many as 4% of all visits to the pediatrician are for complaints of chronic or recurrent abdominal pain.3 As Drs. Saps and Li explain in their article, our understanding of and approach to the diverse functional disorders responsible for these symptoms have markedly increased since the term "Apley Syndrome" was first applied to the problem of "functional abdominal pain."4
In the second article, on gastroesophageal reflux, which I've cowritten with Drs. Suwandhi and Ton, we discuss probably the most common gastrointestinal problem encountered in the first year of life. We also consider its importance during later childhood. At the "other end" of the clinical spectrum, disorders presenting with abdominal complaints in older children, the group of disorders comprising the inflammatory bowel diseases (IBD) is discussed by Drs. Silbermintz and Markowitz. Early recognition of the signs and symptoms of Crohn's disease and ulcerative colitis have led to an improved ability to diagnose and treat these diseases at their earliest stages, thus maximizing the likelihood for a favorable clinical response and prolonged remission. Investigations of Crohn's disease have resulted in significant developments in our understanding of its genetic determinants, exemplified by the description of NOD2/CARD15 variants on chromosome 16.5 In addition, the authors address the marked shift in our current approach to IBD management, from treatment strategies that previously emphasized corticosteroids as the mainstay, to protocols that now include both immunomodulatory and biologic agents as important additions to our therapeutic armamentarium.
Celiac disease affects populations worldwide and likely represents the most common genetically determined disorder found in peoples of European descent.6 Until recently, consideration of a diagnosis of celiac disease was limited to children who presented with signs and symptoms of malabsorption and secondary nutritional deficiencies. While this certainly remains the most common mode of presentation during infancy and early childhood, Drs. Gelfond and Fasano discuss the approach to older children, in whom symptoms may be diminished or even absent. Our understanding of the genetic basis of celiac disease has further allowed the pediatrician to identify individuals who may be at-risk and thus require serologic screening and, ultimately, histopathologic diagnosis.
The remaining two articles consider liver disease. During infancy, problems of neonatal liver disease, encountered in as many as 1 in 2,500 newborns,2 present the clinician with significant challenges in diagnosis and treatment, particularly in the evaluation of cholestasis. Here, Drs. Emerick and Whitington have provided practicing pediatricians with a careful approach to differential diagnostic and management strategies, directed at early identification of surgically treatable lesions.
Finally, the article by Drs. Alfie and Treem discusses the problem of non-alcoholic fatty liver disease (NAFLD), a spectrum of hepatic disorders whose importance in the pediatric age group is only recently being fully appreciated. As the prevalence of childhood obesity continues to rise at an alarming rate,7 the problem of "fatty liver" and its potential to transition to steatohepatitis and cirrhosis must be of increasing concern to primary care pediatricians and pediatric gastroenterologists. Here, screening at-risk children and adolescents is of paramount importance, since NAFLD represents a histological diagnosis that is almost always asymptomatic. Considering current nutritional trends, NAFLD will soon represent (if it does not already represent) the most common pediatric liver disorder in the United States.
Clearly, the articles presented in this issue of Pediatric Annals provide an important introduction to the scope and variety of gastrointestinal and liver disorders that are faced during the course of general pediatric practice, both in infants and in older children. Appreciating their important diagnostic criteria, management alternatives and indications for subspecialist referral will assist the primary care practitioner to educate families regarding these problems, help to understand those environmental and genetic factors that may contribute to disease expression, and develop clinical strategies that improve long-term outcomes.
1. Walker WA, Durie PR, Hamilton JR, Walker-Smith JA, Watkins JB, eds. Pediatric Gastrointestinal Disease. Hamilton, Ontario, Canada: BC Decker; 2000; xvi.
2. Fitzgerald JF. Cholestatic disorders of infancy. Pediatr Clin North Am. 1988; 35(2):357-373.
3. Galler JR, Neustein S, Walker WA. Clinical aspects of recurrent abdominal pain in children. Adv Pediatr. 1980;27: 31-53.
4. Apley J, Naish N. Recurrent abdominal pain: a field survey of 1,000 school children. Arch Dis Child. 1958;33(168): 165-170.
5. Hugot JP, Chamaillard M, Zouali H, et al. Association of NOD2 leucine-rich repeat variants with susceptibility to Crohn's disease. Nature. 200 1;41 1(6837): 599-603.
6. Fasano A, Catassi C. Current approaches to diagnosis and treatment of celiac disease: an evolving spectrum. Gastroenterology. 2001;120(3):636-651.
7. Strauss RS, Pollack HA. Epidemic increase in childhood overweight, 19861998. JAMA. 2001;286(22):2845-2848.