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What is the prevalence of Barrett's mucosa in children and young adults? Do these groups carry particular risk factors?
E. Hassall (Vancouver)
It has been estimated that the prevalence of Barrett's esophagus (BE) in children is 13% of those with reflux esophagitis [1], However, in that study, only two of the 13 "children" described (one of the two was 19 years of age) had specialized Barrett's mucosa with goblet cell metaplasia. Based on our experience at BC Children's Hospital over the last 9 years, I estimate the prevalence of bona fide BE to be less than 2% of children presenting with symptoms of gastroesophageal reflux (GER) or reflux esophagitis.
Of the small number of children with BE, those at higher risk for developing BE are children with neurologic impairment [2], or cystic fibrosis (CF) [3]. Both of these conditions predispose to severe, chronic GER, which is often silent. In both conditions, and in children without these conditions who develop BE, hiatal hernia is present in the majority.
Neurologically impaired children may have one or more of many mechanisms which predispose them to pathologic GER, such as esophageal and gastroduodenal dysmotility, delayed gastric emptying, hiatal hernia, kyphoscoliosis, body casts and prolonged recumbency. When reflux does occur, it is often silent, as central nervous system problems such as severe cerebral palsy and/or mental retardation make verbal or motor responses to esophageal symptoms difficult, subtle, nonspecific or absent [4]. Such children may be apparently asymptomatic or present with "feeding problems"/gagging/recurrent cough, which are often attributed to this underlying neurologic problem alone. Thus, chronic GER in these children often goes unrecognized until presenting with a complication. One recent study showed that mental retardation per se was an independent risk factor for the development of Barrett's esophagus in children and young adults [2]. Another study identified BE in seven of 27 institutionalized adults, but found no higher rate in spastic than in ambulatory patients [5]. Neurologic handicap was present in at least three of nine children and young adults under 25 years of age who presented with adenocarcinoma in a Barrett's esophagus [6].
Due to several pathogenetic mechanisms, children with CF also have a marked predilection to develop pathologic GER [7-9]. In one study [10], 26.5% of CF patients older than 5 years of age reported gastrointestinal symptoms suggestive of reflux (heartburn or regurgitation) compared with only 5.6% of their normal siblings. However, intraesophageal pH studies in CF patients detect a much higher prevalence of pathologic GER [7,11,12], i.e., reflux is silent in the majority of CF patients. Reflux may be silent because gastrointestinal (GI) symptoms may be truly absent, or these symptoms might be relatively ignored by CF patients because of their plethora of other problems. Many patients with CF may consider upper GI symptoms (e.g., heartburn, chest pain, occasional vomiting) as "part of CF" and therefore not report them [3]. Reflux may also cause or contribute to pulmonary disease without causing GI symptoms [8,13] and in CF patients this may go unrecognized in many patients because of their pre-existing pulmonary disease.
Only recently has CF been described as a risk factor for BE [3]. With the high prevalence of pathologic reflux in CF patients, it is surprising that BE had not previously been described in CF. Perhaps BE is truly extremely rare in CF because Barrett's specialized metaplasia takes some years to develop in response to chronic, severe GER [14,15] and the life span of CF patients is relatively short. However, BE does occur in children with chronic, severe reflux, and the median life span in CF has doubled from 14 to 28 years between 1969 and 1990 [16], i.e., ample life span for BE to occur and be detected. A more plausible explanation is that cases of BE are being missed in children and young adults with CF. A likely reason for this is reflected in the literature which shows an apparent reluctance to perform detailed endoscopy with documentation of landmarks and multiple esophageal biopsies in patients with CF. In most reports of esophageal disease in CF, the diagnosis of esophagitis has been made by inference without endoscopy [7,17-19], or by naked eye endoscopy without multiple biopsies [17,18,20]. Similar comments regarding reluctance to perform endoscopy with biopsies apply to neurologically handicapped children.
It is well recognized that Barrett's mucosa shows decreased pain sensitivity compared with that of esophageal squamous mucosa, hence the predilection for late presentation of BE, i.e., with complications. In children with CF or neurologic impairment, the silence of the pathologic reflux itself makes these groups doubly at risk for having reflux missed.
While Barrett's esophagus carries its own morbidity and implications, in CF and the neurologically impaired, its additional importance is that it is a marker for particularly severe reflux which may exacerbate the nutritional and pulmonary problems of both these groups of patients.
Children with CF should be closely questioned for the presence of upper GI symptoms. Patients with even apparently mild symptoms should undergo upper GI endoscopy with documentation of landmarks, multiple biopsies and recording of the sites of origin of biopsies relative to the landmarks. Similarly, handicapped children may benefit from sensitive vigilance and earlier diagnostic studies. Both groups stand to benefit from earlier diagnosis of GER and of Barrett's esophagus, since effective medical and surgical treatment of reflux is available [21,22].
Another group of children who may be at risk for development of BE are those with a positive family history of proven BE, based on anecdotal reports of families with BE [15]. However, the magnitude of this risk is as yet not quantifiable, as there are no extensive studies screening the offspring of affected parents.
References
15. Hassall E. Barrett's esophagus: congenital or acquired? Am J Gastroenterol 1993:88:819-824.
16. Fitzsimmons SC. The changing epidemiology of cystic fibrosis. J Pediatr 1993:122:1-9.