Pathologic aerophagia is caused by the swallowing of excessive volumes of air and causes various gastrointestinal symptoms, such as burping, abdominal cramps, flatulence and a reduced appetite (1). Pathologic childhood aerophagia (PCA) is a clinical entity that simulates pediatric gastrointestinal motility disorders and is rarely recognized and often poorly treated in children (2). In some cases, severe aerophagia causes massive bowel distention and can lead to ileus, volvulus and even intestinal necrosis or perforation (3,4).
Although early recognition and diagnosis of PCA is vitally required to avoid unnecessary, expensive diagnostic investigations and serious complications, PCA is rarely discussed in the literature and few case reports are available on aerophagia in childhood (1,2,4-7). This analysis of PCA patients showed that they shared several common features that can be easily recognized and diagnosed.
PATIENTS AND METHODS
We retrospective reviewed and analyzed the data of 42 consecutive PCA patients (26 female, 16 male), aged 2 to 16 years, diagnosed between March 1995 and July 2003. Patients were recruited from the inpatient and outpatient units of the Dongsan Medical Center, Keimyung University School of Medicine. Informed consent was obtained from all parents of children enrolled into this study. All study procedures and record reviews were approved by the Keimyung University Institutional Review Board. Data was collected by reviewing medical charts and the following were recorded and analyzed; age, symptom duration before diagnosis, chief complaints, history of abdominal distention, physical examination details, abdominal and chest radiography, underlying associations and identified psychological stress factors. Clinical assessment of mental retardation was performed by Denver Developmental Screening Test or Social Maturity Scale. Psychological stress factor was identified by Korean version of Stressful Life-Change Event Scale (8). Parents provided rating of stress in the patient's environment.
Fluoroscopic Diagnosis of Pathologic Aerophagia
A diagnosis of PCA was accepted if the observed symptomatic abdominal distention was attributable to swallowing air, as confirmed by fluoroscopy, and if it was not attributable to any gastrointestinal disease; ie, mechanical intestinal obstruction, chronic intestinal pseudo-obstruction, bacterial overgrowth, Hirschsprung disease or malabsorption. These pathologies were considered initially and then ruled out by clinical findings and progress, bowel transit time using sitz marker or gastrofiberscopic mucosal biopsy if necessary. We did not use the clinical features and symptom duration as detailed in the Rome II criteria (9,10) to diagnose PCA. The diagnosis of pathologic aerophagia, based on the fluoroscopic observation, was defined as the involuntary paroxysmal openings of cricopharyngeal sphincter followed by air swallows without oropharyngeal swallowing movement sequences.
Esophageal Air Sign
An esophageal air sign (EAS) was defined as an abnormal air shadow on the proximal esophagus adjacent to the trachea (Fig. 1A) in at least one of two serial full-inflated chest radiographs taking at 2-minute intervals. EAS should not be observed theoretically in normal full-inflated chest radiograph because of closure of cricopharyngeal sphincter resulting in no entry of air into the esophagus. The presence of EAS was evidence of abnormal air swallowing, as was confirmed by fluoroscopy (Fig. 1B). During the fluoroscopic investigation, patients were asked to hold swallowing saliva. When swallowed air, resulting from the involuntary paroxysmal cricopharyngeal opening, was located in the proximal esophagus, it was not easily moved to the distal esophagus because swallowed air has too small a volume to trigger esophageal peristalsis to the distal esophagus. Sixty-second fluoroscopic observations showed that a bolus of swallowed air stayed for as long as 40 seconds in the proximal esophagus and that additional air swallowing stimulated esophageal peristalsis and moved the bolus to the distal esophagus. We observed that an involuntary air swallow occurred within 2 minutes. Hence, we took two serial chest radiographs taken at 2-minute intervals and tried to find EAS in at least one. When taking two serial chest radiographs, patients were asked to hold swallowing of saliva for 2 minutes before and during taking chest radiographs. The controls used for EAS were the randomly selected chest radiographs of 124 age-matched patients who were admitted into the inpatient ward with various diagnoses but not otolaryngologic or neurologic disease.
The χ2 test was used for statistical analysis. Statistical significance was accepted if P < 0.05. Data are presented as mean ± SD.
Age and Symptom Duration
The average age of the 42 PCA patients was 6.4 ± 3.5 years (range, 2 to 16 years). Mean symptom duration before diagnosis was 10.6 ± 13.5 months (range, 1 to 60 months) and 16 (38.1%) patients had symptom duration exceeding 12 months.
Of the 42 patients, the chief complaints were abdominal distention (52.4%), recurrent abdominal pain syndrome (21.4%), chronic diarrhea (11.9%), acute abdominal pain (7.1%), malnutrition (2.4%), vomiting (2.4%) and soiling (2.4%). Soiling patients did not have functional fecal retention syndrome or neuromuscular disorder. The clinical features that were common to all patients were abdominal distention that progressively increased during the course of a day and reached a maximum in the evening (Fig. 2), increased flatus during sleep and increased bowel sounds on auscultation. Abdominal radiographs of all patients, taken in the late afternoon, showed an air-distended stomach and increased gas in the small and large bowel without signs of obstruction (Fig. 2B). Visible or audible air swallowing were noted in 11 (26.2%) patients and diarrhea (23.8%), repetitive belching (9.5%), constipation (7.1%) and other symptoms (7.2%) were also noted (Table 1). Three patients with constipation had pathologic aerophagia incidentally combined with functional fecal retention syndrome.
Esophageal Air Sign
EAS (Fig. 1) was observed in 76.2% of the 42 patients and in 9.7% of the 124 controls (P = 0.0001). In EAS-positive (including suspicious cases) controls, most of chest radiographs showed relatively hypo-inflated conditions.
Underlying Associations and Psychological Stress Factors
The subgroups of PCA divided by underlying associations were PCA without severe mental retardation (76.2%), which consisted of psychological stresses (78.1%) and uncertain condition (21.9%), and PCA with severe mental retardation (23.8%). Of the 25 patients with psychological stresses, PCA was precipitated by the following problems: school or preschool entrance stress (32.0%), birth of siblings (20.0%), working mother (16.0%), divorce of parents (8.0%), being scolded (8.0%), psychosis of mother (4.0%), hospital admission (4.0%), toilet training (4.0%) and trouble with a sibling (4.0%).
The Rome II criteria (9,10) for diagnosis of PCA suggested that children must have at least two of the following signs and symptoms for at least 12 weeks, which need not be consecutive, in the preceding 12 months to be diagnosed with pathologic aerophagia: air swallowing, abdominal distention from intraluminal air and repetitive belching and/or increased flatus. Our observations indicate that the Rome II criteria for aerophagia should be detailed and made clearer in its clinical profiles and symptom durations if they are to serve as diagnostic criteria for PCA.
First, we retrospectively observed that symptom duration before diagnosis was within 12 weeks in the 12 (28.6%) PCA patients. We doubt very much that the symptom duration should be necessary criteria for diagnosis of PCA. The diagnostic criteria of functional gastrointestinal disorders, like a recurrent abdominal pain, need a criterion of symptom duration because of their obscure clinical characteristics and pathologies. However, we observed that pathologic aerophagia seems to be the result of repetitive air swallows resulting from involuntary paroxysmal openings of the cricopharyngeal sphincter of the esophagus associated with mental retardation or psychological stresses. Observation of this definite pathologic finding may induce a diagnosis of pathologic aerophagia regardless of its symptom duration.
Second, although increased flatus was noted during the phase of progressive abdominal distention, it was mainly observed during sleep in this study. Increased flatus during sleeping is suspected to occur as a result of increased parasympathomimetic activity during sleeping that causes increased gastrointestinal motility. Hence, a non-distended abdomen in the morning may be achieved by increased flatus during sleep and presumably by gastrointestinal absorption of gas. Also, the involuntary cricopharyngeal sphincter openings may be presumed to disappear during sleep, resulting in a non-distended abdomen in the morning. We suggest that the characteristic features of increased flatus and abdominal distention of Rome II criteria should be detailed.
Third, after educating parents in terms of gulping sounds or movements suggestive of air swallowing that they recognized (1), we found that air swallowing and repetitive belching were more infrequent than suggested by the Rome II criteria. Hence, air swallowing, visible or audible, or increased belching represent supportive evidence for the diagnosis of pathologic aerophagia but are not sufficient to serve as diagnostic criteria.
Our observations show that the following common manifestations of PCA are more satisfactory diagnostic criteria: abdominal distention that progressively increases during the course of the day (minimum in the early morning and a maximum in the late evening), increased flatus during sleep, increased bowel sounds on auscultation of distended abdomen and an abdominal radiograph taken in the late afternoon showing an air-distended stomach and increased gas in the small and large bowel without signs of obstruction. We also find that abdominal distention with these characteristic findings is clinically available for the differential diagnosis of PCA from various pediatric gastrointestinal motility disorders, such as pseudoobstruction or Hirschsprung disease.
EAS should not be observed theoretically in a normal full-inflated chest radiograph, because of the closure of the cricopharyngeal sphincter of the esophagus. We took two serial chest radiographs at 2-minute intervals and tried to find EAS in at least one. When taking two serial chest radiographs, patients were asked to hold swallowing of saliva for 2 minutes before and during taking chest radiographs. EAS was observed in 76.4% of the 42 patients but in only 9.7% (including suspicious ones) of the 124 randomly selected controls. EAS was not observed on control chest radiographs with full inspiration. Most of the control radiographs that presumably showed EAS positive were found to be related with relatively hypo-inflated radiographic conditions. Thus, we suggest that EAS on the normal full-inflated chest radiographs is a helpful sign for the early diagnosis of PCA. However, EAS may not be a specific marker for pathologic aerophagia. This sign may be just a supportive evidence for the early recognition of pathologic aerophagia.
The subgroups of PCA divided by underlying associations were PCA without severe mental retardation, which consisted of psychological stresses and uncertain conditions, and PCA with severe mental retardation. The PCA without severe mental retardation is known to be usually self-limited, lasting weeks or months, but may last much longer (1,2,6). Of 25 patients with psychological stresses, PCA was precipitated by underlying stresses. These psychological stress factors were problems that are frequently encountered during child development. The PCA patients are very sensitive individuals (5). One patient with psychological stress in this study had recently become enuretic. Four patients of PCA with identified psychological stress factors were suspected to have introverted personalities. The psychiatric dynamics of PCA patients should be further evaluated.
Pathologic aerophagia is present in 8.8% of the institutionalized mentally retarded population (11). Behaviorists have described aerophagia in patients with mental retardation or neurologic disorders as a habitual means of self destruction or as a way of dealing with boredom (4,7). In these severe mental retardation patients, severe aerophagia causes massive distention of the bowel, possibly leading to surgical emergencies such as ileus, volvulus and even intestinal necrosis or perforation (3,4). The placement of a percutaneous endoscopic gastrostomy catheter to act as a desufflator has been suggested to prevent surgical emergencies or hindered respiration as a result of extreme diaphragm elevation (3).
In reported pediatric cases of pathologic aerophagia (1,2,4-6), the correct diagnosis was initially missed in most. Parents may deny that their children swallow air because they may not realize that it is happening. From our observations, the symptom duration before diagnosis exceeded 12 months in 38.1% of PCA patients. Early recognition and a correct diagnosis help alleviate parents’ or patient's anxiety and prevent unnecessary testing, treatments and hospital admissions (1,6). Our observations show that the diagnostic clinical profiles suggested by Rome II should be detailed and clarified if they are to serve as clinical diagnostic criteria for PCA.
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Keywords:© 2005 Lippincott Williams & Wilkins, Inc.
Aerophagia; Childhood; Diagnosis