Aerophagia in children: characterization of a functional gastrointestinal disorder

The purpose of this study was to describe presenting symptoms, diagnostic testing, treatments and outcomes in a group of children with a diagnosis of aerophagia. A computerized diagnostic index was used to identify all children between the age of 1 and 17 years diagnosed with aerophagia at a tertiary care medical centre between 1975 and 2003. Individual medical charts were abstracted for information on the demographics, clinical features, co-morbid diagnoses, diagnostic work up and treatment of children with aerophagia. Information on presenting symptoms was also collected for a group of children who were retrospectively classified as having functional dyspepsia for comparison (n = 40). Forty-five children had a diagnosis of aerophagia. The mean duration of symptoms in children with aerophagia was 16 +/- 5 months. The most common gastrointestinal symptoms were abdominal pain, distention and frequent belching. Children with functional dyspepsia had a higher prevalence of nausea, vomiting, abdominal pain and unintentional weight loss compared to children with aerophagia (all P < 0.05). In conclusion, aerophagia is a disorder that is diagnosed in neurologically normal males and females, who can experience prolonged symptoms. Although many children with aerophagia present with upper gastrointestinal symptoms, the disorder appears to be distinct from functional dyspepsia.

Sleeve sensor versus high-resolution manometry for the detection of transient lower esophageal sphincter relaxations

Transient lower esophageal sphincter relaxations (TLESRs) are the most important mechanism by which gastroesophageal reflux occurs, and sleeve sensor manometry is the gold standard for detection of TLESRs. The aim of this study was to evaluate manometry with closely spaced sideholes (high-resolution manometry) for the detection of TLESRs as an alternative. In 12 patients with gastroesophageal reflux disease, a 90-min postprandial manometry was performed by using a catheter incorporating both a sleeve sensor and closely spaced sideholes in the esophagogastric junction. TLESRs recorded with both techniques were scored. Reflux during TLESRs was detected by using manometry (common cavity), intraluminal impedance, and pH monitoring. A total of 145 TLESRs were detected by using both techniques, 117 with high-resolution manometry and 108 with sleeve sensor manometry [not significant (NS)]. Manometric signs of reflux during TLESRs detected with high-resolution and sleeve sensor manometry were found in 62.4 and 56.5%, NS, respectively, versus 38.5 and 35.2%, NS on pH-metry and 70.1 and 60.2%, NS on impedance monitoring. TLESRs recognized only with high-resolution manometry were more often accompanied by reflux, as detected with manometry (59.5%) and impedance monitoring (67.6%), than TLESRs recognized only with sleeve sensor manometry (32.1 and 28.6%). High-resolution manometry is at least as accurate as sleeve sensor manometry for the detection of TLESRs.

Relationships between air swallowing, intragastric air, belching and gastro-oesophageal reflux

BACKGROUND

With each swallow a certain amount of air is transported to the stomach. The stomach protects itself against excessive distention by swallowed air through belching (gas reflux). The mechanism of belching (transient lower oesophageal sphincter relaxation) is also one of the mechanisms underlying gastro-oesophageal reflux.

AIM

To investigate whether swallowing of air leads to an increase in size of the intragastric air bubble and to gastro-oesophageal reflux.

METHODS

Multichannel intraluminal impedance measurement was used to quantify the incidence of swallowing of air in 20 healthy volunteers before and after a meal. Radiography was used to measure the size of the intragastric air bubble. Gastro-oesophageal reflux was assessed by concurrent impedance and pH measurement.

RESULTS

The rate of air swallowing was correlated to the size of the intragastric air bubble postprandially and to the rate of gaseous gastro-oesophageal reflux. The number of air swallows and the size of the intragastric air bubble did not correlate with the number of liquid acid and non-acid reflux episodes.

CONCLUSIONS

In healthy subjects, air swallowing promotes belching but does not facilitate acid reflux.

Role of oxidative stress in the pathogenesis of septic ileus in mice

We investigated the role of oxidative stress in the pathogenesis of septic ileus. Sepsis was induced by intraperitoneal (i.p.) injection of lipopolysaccharides (LPS, 20 mg kg(-1)) in mice. The effect of two i.p. injections of superoxide dismutase [polyethylene glycol (PEG)-SOD, 4000 U kg(-1)] and catalase (PEG-CAT, 15,000 U kg(-1)) was investigated on gastric emptying, intestinal transit and total nitrite plasma concentrations. We also performed immunohistochemical experiments on gastric and ileal tissue. LPS significantly delayed gastric emptying and intestinal transit while plasma nitrite levels increased. Polyethylene glycol (PEG)-SOD reversed the endotoxin-induced delay in gastric emptying and improved the delay in intestinal transit without effect on plasma nitrite levels. PEG-CAT slightly improved the delay in gastric emptying without effect on intestinal transit. Immunohistochemistry showed the presence of nitrotyrosine (NT) and 4-hydroxy-2-nonenal (HNE) in the gastric and ileal mucosa of LPS-treated mice. Treatment with PEG-SOD or PEG-CAT of LPS mice diminished the presence of NT or HNE in both tissues. In addition, LPS induced a significant increase in inducible nitric oxide synthase (iNOS)-positive residential macrophages in the external musculature of stomach and ileum, which significantly decreased after PEG-SOD or PEG-CAT treatment. The present results support a role for oxidative and nitrosative stress in the pathogenesis of septic ileus in mice.

Reproducibility of multichannel intraluminal electrical impedance monitoring of gastroesophageal reflux

OBJECTIVE

Esophageal impedance measurement is a novel method for gastroesophageal reflux monitoring. Reproducibility is an important aspect of every biomedical test. The aim of this study was therefore to asses the reproducibility of gastroesophageal reflux monitoring using impedance measurements.

METHODS

Impedance and pH signals were recorded in 20 healthy volunteers during 90-min postprandial periods on two separate days. Hourly rates of gas, liquid, and mixed gas-liquid reflux episodes were measured in each recording period as well as percentage of time with pH < 4 and rate of acid reflux episodes. As a quantitative description of inter- and intraindividual variation for each variable, the mean percentage of covariation (100 x SD/mean: %COV) was calculated. As a second measure for reproducibility, Kendall's coefficients of concordance (W values) were calculated.

RESULTS

For all variables, interindividual %COV was at least 50% higher than intraindividual %COV. Statistically significant concordances were found for gas reflux (W = 0.81, p= 0.04) and mixed reflux (W = 0.85, p= 0.03) while concordance for liquid reflux tended to be significant (W = 0.75, p= 0.08). This was comparable to the reproducibility of the number of acid reflux episodes and percentage of time with pH < 4 (W = 0.78, p= 0.05 and W = 0.88, p= 0.02, respectively).

CONCLUSIONS

Postprandial gastroesophageal reflux data assessed with impedance monitoring are as reproducible as assessed with pH monitoring.

Minimum sample frequency for multichannel intraluminal impedance measurement of the oesophagus

In all systems for impedance monitoring signals are stored in digital format after analog-to-digital conversion at a predefined rate, the sample frequency. We aimed to find the minimum sample frequency required to evaluate oesophageal transit and gastro-oesophageal reflux studies using impedance monitoring. In 10 healthy subjects and five patients with gastro-oesophageal reflux disease impedance signals were acquired during a 90-min postprandial period, using a sample frequency of 1000 Hz. Additionally, 10 liquid swallows were recorded in the healthy subjects. A dedicated computer program was used to derive, from the original 1000-Hz files, series of new data files with sample frequencies of 500, 200, 100, 50, 20, 10, 8, 5 and 4 Hz. In all of these files, liquid and gas reflux events were identified. In the analysis of the swallows, bolus head advance time (BHAT) and total bolus transit time were measured. Reflux events were detectable down to a sample frequency of 50 Hz. In transit analysis errors for BHAT at frequencies below 8 Hz errors exceeded 2.5%. Therefore, in impedance monitoring the minimum sample frequency is 50 Hz for the detection of reflux and 8 Hz for the evaluation of oesophageal transit.

Aerophagia, gastric, and supragastric belching: a study using intraluminal electrical impedance monitoring

BACKGROUND

Patients with aerophagia are believed to have excessive belches due to air swallowing. Intraluminal impedance monitoring has made it possible to investigate the validity of this concept.

METHODS

The authors measured oesophageal pH and electrical impedance before and after a meal in 14 patients with excessive belching and 14 healthy controls and identified patterns of air transport through the oesophagus. The size of the gastric air bubble was measured radiographically. In four patients prolonged oesophageal manometry was performed simultaneously.

RESULTS

In all subjects, impedance tracings showed that a significant amount of air is propulsed in front of about a third of the swallow induced peristaltic waves. Two types of retrograde gas flow through the oesophagus (belch) were observed. In the first type air flowed from the stomach through the oesophagus in oral direction ("gastric belch"). In the second type air entered the oesophagus rapidly from proximal and was expulsed almost immediately in oral direction ("supragastric belch"). The incidence of air-containing swallows and gastric belches was similar in patients and controls but supragastric belches occurred exclusively in patients. There was no evidence of lower oesophageal sphincter relaxation during supragastric belches. Gastric air bubble size was not different between the two groups.

CONCLUSIONS

In patients with excessive belching the incidence of gaseous reflux from stomach to oesophagus is similar to that in healthy subjects. Their excess belching activity follows a distinct pattern, characterised by rapid antegrade and retrograde flow of air in the oesophagus that does not reach the stomach.

Double-peaked high-pressure zone at the esophagogastric junction in controls and in patients with a hiatal hernia: a study using high-resolution manometry

The lower esophageal high-pressure zone (HPZ) consists of the intrinsic lower esophageal sphincter (LES) and the diaphragmatic sphincter. In patients with a hiatal hernia these constituents are separated. We performed high-resolution manometry of the esophagogastric HPZ in six controls, six patients with a small hernia, and six patients with a large hernia. Prevalence of a double-peak pressure profile of the HPZ was noted. Pressures and distances between the peaks were assessed. Prevalence of the double-peak profile was similar between patients with a small hernia and controls, but patients with a large hernia showed a higher prevalence with inspiration (P < 0.05) than the others. The distance between the two peaks was larger in patients with a large hernia (P < 0.05). In conclusion, high-resolution manometry makes it possible to distinguish the diaphragmatic pressure component from the LES. Two pressure peaks can be found both in hernia patients and in healthy volunteers.

The role of pelvic floor dysfunction and slow colonic transit in adolescents with refractory constipation

OBJECTIVE

Although pelvic floor dysfunction (PFD) is recognized as a cause of refractory constipation in adults, this diagnosis is not frequently considered in children and adolescents with refractory constipation. The purpose of this study was to examine the symptoms and colonic transit in adolescents with constipation evaluated for a disorder in pelvic floor function.

METHODS

Adolescents with refractory constipation who had undergone anorectal manometry (ARM) and balloon expulsion test (BET) were identified by retrospective review of records. Initial symptoms and the clinician's assessment were used to categorize patients by pediatric Rome II criteria, that is, functional constipation (FC), constipation-predominant irritable bowel syndrome (C-IBS) or functional fecal retention (FFR). Results of scintigraphic colonic transit studies were evaluated. A chi2 test was used to assess the association between individual clinical symptoms and Rome II criteria.

RESULTS

Sixty-seven adolescents underwent evaluation of pelvic floor function by tests for PFD: BET was abnormal in 42%. There was no underlying disease or alternative diagnosis to account for the constipation in these patients. Among the 41 patients who also underwent scintigraphic colonic transit, 30% had slow transit constipation and 12% had both slow colonic transit and abnormal BET. Patients classified as C-IBS were more likely to report weight loss (p = 0.03), bloating (p = 0.04), and incomplete rectal evacuation (p = 0.03).

CONCLUSION

Abnormal pelvic floor function and delayed colonic transit are demonstrable as single or combined problems in adolescents with refractory constipation.

Functional dyspepsia, upper gastrointestinal symptoms, and transit in children

OBJECTIVE

To assess the prevalence of abnormal gastric emptying and small bowel transit in children with functional dyspepsia at a tertiary care center, and the relationship between abnormal gastric and small bowel transit and symptoms in pediatric patients with functional gastrointestinal disorders.

STUDY DESIGN

Patients were selected by a cross-sectional chart review based on the following inclusion criteria: (1) completion of scintigraphic study of the gastric emptying of solids at 2 hours (GE2), 4 hours (GE4), and small bowel transit at 6 hours (SBT) using a standardized egg meal labeled with 99mTechnetium sulfur colloid, and (2) gastrointestinal (GI) complaints without mucosal or organic disease. Logistic regression analysis was used to assess the association between the presence of upper GI symptoms, and each parameter of gastric and small bowel transit.

RESULTS

Children with upper GI symptoms (n=96) were identified. Among 57 children with functional dyspepsia, 40% had slow SBT. Fast GE at 4 hours, and slow SBT were independently associated with bloating. Children with fast SBT were less likely to report abdominal pain.

CONCLUSION

Incorporating assessments of gastric and small bowel transit may be useful in the evaluation of pediatric patients with upper GI symptoms and functional dyspepsia.

The gastro-oesophageal pressure inversion point revisited

BACKGROUND

The pressure inversion point (PIP) is defined as the point at which, during stationary pull-through manometry of the oesophago-gastric junction, the polarity of the respiratory-associated pressure variations changes. Traditionally, the PIP is ascribed to transition of the pressure sensor from the abdominal to the thoracic cavity. We used high-resolution manometry to investigate the validity of this concept in six healthy volunteers and six patients with a sliding hiatus hernia.

METHODS

In the analysis, the position of the PIP was identified. When there was a second, more distal, PIP, its position was also noted. The amplitude of the respiratory-associated pressure variations, defined as the difference between end-expiratory and end-inspiratory pressure, was measured.

RESULTS

Double PIPs were found both in healthy controls (23 +/- 8% of time) and in patients (38 +/- 9% of time). Amplitudes of the respiratory-associated pressure variations were significantly higher at the proximal and distal border of the PIP (3.36 +/- 0.2 kPa and 2.29 +/- 0.2 kPa) than in the oesophageal body (0.54 +/- 0.03 kPa, P < 0.001) and in the stomach (0.54 +/- 0.03 kPa, P < 0.001). We also observed a relationship between the localization of the highest end-expiratory pressure and the position of the PIP. During TLOSRs respiratory variation amplitudes at the proximal and distal border of the PIP decreased to 0.61 +/- 0.02 kPa and 0.29 +/- 0.01 kPa, approximating respiratory pressure variation in oesophagus and stomach.

CONCLUSION

Our findings suggest that the PIP is caused by sliding of the high-pressure zone along pressure sensors rather than by the transition from the thoracic to the abdominal compartment.

Systematic review and meta-analysis: does gall-bladder ejection fraction on cholecystokinin cholescintigraphy predict outcome after cholecystectomy in suspected functional biliary pain?

BACKGROUND

Patients with suspected functional biliary pain often undergo cholecystectomy if a decreased gall-bladder ejection fraction (GBEF <35%) is demonstrated by cholecystokinin cholescintigraphy. However, the validity of GBEF in predicting which patients will have symptomatic relief following cholecystectomy is unclear.

AIM

To determine whether patients with suspected functional biliary pain with decreased GBEF have a better symptomatic outcome after cholecystectomy than those with normal GBEF.

METHODS

Systematic review and meta-analysis of the published literature through MEDLINE and EMBASE databases.

RESULTS

We included nine studies with a total of 974 patients with suspected functional biliary pain; 362 patients underwent cholecystectomy. Most studies assessed outcome by direct patient interview. Mean ages across the studies ranged from 35 to 47 years; 78% of all patients were female. Mean duration of follow-up after surgery ranged from 1 to 2.5 years. After cholecystectomy, 94% of the patients with reduced GBEF had a positive outcome compared to 85% among those with normal GBEF. The pooled Mantel-Haenszel odds ratio for positive outcome was 1.37 (95% confidence interval 0.56-3.34), P=0.56.

CONCLUSION

These data do not support the use of GBEF to select patients with suspected functional biliary pain for cholecystectomy. Prospective randomized trials are required if this practice is to be evidence-based.

Gastric accommodation and emptying in evaluation of patients with upper gastrointestinal symptoms

BACKGROUND & AIMS

Endoscopy-negative dyspepsia is a common symptom that often is difficult to define in pathophysiologic terms. The aim of this study was to assess the frequency of disordered gastric accommodation and emptying in patients referred with unexplained upper gastrointestinal symptoms.

METHODS

A computerized diagnostic index was used to identify all patients, 18-70 years old, who underwent single-photon emission computed tomography (SPECT) to assess gastric accommodation at Mayo Clinic Rochester over a 3-year period. Demographics, clinical features, and results of diagnostic testing, including scintigraphic gastric emptying, were extracted from the electronic record.

RESULTS

A total of 214 patients were identified; the primary clinical diagnoses were functional dyspepsia, postfundoplication syndromes, rumination syndrome, and diabetic dyspepsia. Gastric accommodation was impaired in 43% of the whole group: 47% of functional dyspepsia, 44% of postfundoplication syndromes, and 33% of diabetic dyspepsia. Delayed gastric emptying was most prevalent in diabetic dyspepsia, and was accelerated in postfundoplication syndromes groups. Thirty-seven percent of patients had abnormal gastric emptying. The highest prevalence of delayed gastric emptying was in the diabetic dyspepsia and accelerated gastric emptying in postfundoplication syndromes groups. Twenty-five percent of patients with normal gastric emptying had impaired accommodation. Upper-gastrointestinal symptoms were not different in groups based on gastric accommodation or emptying results.

CONCLUSIONS

Impaired gastric accommodation is common in patients with unexplained dyspepsia. Symptoms alone cannot predict physiologic disturbances. These noninvasive tests identify single or combined pathophysiologic disturbances and may help to identify subgroups of patients as candidates for more selective pharmacotherapy in the future.

Gastric accommodation and emptying in evaluation of patients with upper gastrointestinal symptoms

BACKGROUND & AIMS

Endoscopy-negative dyspepsia is a common symptom that often is difficult to define in pathophysiologic terms. The aim of this study was to assess the frequency of disordered gastric accommodation and emptying in patients referred with unexplained upper gastrointestinal symptoms.

METHODS

A computerized diagnostic index was used to identify all patients, 18-70 years old, who underwent single-photon emission computed tomography (SPECT) to assess gastric accommodation at Mayo Clinic Rochester over a 3-year period. Demographics, clinical features, and results of diagnostic testing, including scintigraphic gastric emptying, were extracted from the electronic record.

RESULTS

A total of 214 patients were identified; the primary clinical diagnoses were functional dyspepsia, postfundoplication syndromes, rumination syndrome, and diabetic dyspepsia. Gastric accommodation was impaired in 43% of the whole group: 47% of functional dyspepsia, 44% of postfundoplication syndromes, and 33% of diabetic dyspepsia. Delayed gastric emptying was most prevalent in diabetic dyspepsia, and was accelerated in postfundoplication syndromes groups. Thirty-seven percent of patients had abnormal gastric emptying. The highest prevalence of delayed gastric emptying was in the diabetic dyspepsia and accelerated gastric emptying in postfundoplication syndromes groups. Twenty-five percent of patients with normal gastric emptying had impaired accommodation. Upper-gastrointestinal symptoms were not different in groups based on gastric accommodation or emptying results.

CONCLUSIONS

Impaired gastric accommodation is common in patients with unexplained dyspepsia. Symptoms alone cannot predict physiologic disturbances. These noninvasive tests identify single or combined pathophysiologic disturbances and may help to identify subgroups of patients as candidates for more selective pharmacotherapy in the future.

Effect of inhibition of inducible nitric oxide synthase and guanylyl cyclase on endotoxin-induced delay in gastric emptying and intestinal transit in mice

Nitric oxide (NO) is postulated to play a role in endotoxin-induced ileus. We investigated the effect of selective blockade of inducible NO synthase (iNOS) and guanylyl cyclase on endotoxin-induced ileus in mice. Thirty minutes before injection of lipopolysaccharides (LPS), mice were pretreated with L-NAME (N omega-nitro-L-arginine methyl ester, non-selective NOS inhibitor), 1400W (N-(3-(aminomethyl)benzyl)acetamide, selective iNOS inhibitor), ODQ (1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one, guanylyl cyclase inhibitor), dimethyl sulfoxide (DMSO, vehicle), or dexamethasone. After 18 h, general well being deteriorated and the mice developed hypothermia and a significant delay in gastric emptying and intestinal transit as measured by Evans blue. 1400W completely reversed the endotoxin-induced delay in gastric emptying, while L-NAME did not have these beneficial effects. On the contrary, even in control mice, L-NAME delayed gastric emptying. Dexamethasone, DMSO, and ODQ mimicked the effect of 1400W on endotoxin-induced delay in gastric emptying. The endotoxin-induced delay in transit was significantly improved only by 1400W. None of the drugs reversed the hypothermia. In LPS mice treated with L-NAME, the behavior scale increased even further, while it decreased after treatment with 1400W. In conclusion, selective inhibition of iNOS reverses the endotoxin-induced delay in gastric emptying and transit and improves general well being. The pathway used by NO, derived from iNOS, may involve inhibition of guanylyl cyclase or radical scavenging.