Oesophageal function and symptoms in moderate and severe asthma

Maternal history of asthma modifies the risk of childhood persistent asthma associated with maternal age at birth: Results from a large prospective cohort in Canada

BACKGROUND

Asthma is a prevalent disease that affects many Canadians. Persistent asthma can affect quality of life, and has multiple health implications. Maternal age at birth has been associated with many adverse health outcomes in children. Conflicting study results exist regarding maternal age at birth and childhood asthma. The association between maternal age at birth and persistent asthma in children is still unknown.

OBJECTIVE

To investigate the relationship between maternal age at birth and persistent asthma in children at ten years of age.

METHODS

This is a prospective cohort study including all children aged 0-2 years who took part in the first cycle of the National Longitudinal Survey of Children and Youths (NLSCY) and were followed every two years until eight to ten years of age in Cycle 5. An interaction term between maternal age at birth and maternal asthma history was introduced in a multivariate model to examine modification effects of maternal asthma history on the association.

RESULTS

Multivariate logistic regression demonstrated that older maternal age at birth was significantly associated with an increased risk of childhood persistent asthma in mothers with a history of asthma (OR = 1.20, 95% CI: 1.04-1.40, p = .016). No relationship was found in mothers without a history of asthma.

CONCLUSION

Maternal history of asthma has an impact on the association between maternal age at birth and childhood persistent asthma in children by age ten. The finding may help explain the inconsistent results in the literature regarding the risk of asthma associated with maternal age at birth.

Diagnostic value of a pattern of exhaled breath condensate biomarkers in asthmatic children

BACKGROUND

Diagnosing asthma in children is a challenge and using a single biomarker from exhaled breath condensate (EBC) showed the lack of improvement in it.

OBJECTIVE

The aim of this study was to assess the diagnostic potential of a pattern of simple chemical biomarkers from EBC in diagnosing asthma in children in a real-life setting, its association with lung function and gastroesophageal reflux disease (GERD).

METHODS

In 75 consecutive children aged 5-7 years with asthma-like symptoms the following tests were performed: skin prick tests, spirometry, impulse oscillometry (IOS), exhaled NO (F_ENO), 24-hour oesophageal pH monitoring and EBC collection with subsequent analysis of pH, carbon dioxide tension, oxygen tension, and concentrations of magnesium, calcium, iron and urates.

RESULTS

No significant differences were found for individual EBC biomarkers between asthmatics and non-asthmatics (p>0.05 for all). A pattern of six EBC biomarkers showed a statistically significant (p=0.046) predictive model for asthma (AUC=0.698, PPV=84.2%, NPV=38.9%). None to moderate association (R² up to 0.43) between EBC biomarkers and lung function measures and F_ENO was found, with IOS parameters showing the best association with EBC biomarkers. A significantly higher EBC Fe was found in children with asthma and GERD compared to asthmatics without GERD (p=0.049).

CONCLUSIONS

An approach that involves a pattern of EBC biomarkers had a better diagnostic accuracy for asthma in children in real-life settings compared to a single one. Poor to moderate association of EBC biomarkers with lung function suggests a complementary value of EBC analysis for asthma diagnosis in children.

Asthma and overweight are associated with symptoms of gastro-oesophageal reflux

AIM

To explore the prevalence of symptoms suggestive of gastro-oesophageal reflux disease (GERD) in asthmatics and controls, and to control for the possible effect of overweight.

METHODS

The prevalence of GERD symptoms was assessed using a questionnaire about reflux symptoms in children with asthma (n=872, mean age 10.4 y, 65% males) compared to non-asthmatic controls (n=264, mean age 10.8 y, 48% males), and a symptom score was calculated. The association between GERD symptoms and overweight (age-adjusted BMI > 25) was assessed independently.

RESULTS

A positive reflux symptom score was found in 19.7% of the asthmatics compared to 8.5% of the non-asthmatic control group (odds ratio (OR) 2.6, 95% CI 1.7-4.2). Overweight children reported GERD symptoms more frequently than children with normal weight (OR 1.8, 95% CI 1.2-2.6). Asthma and obesity remained significant predictors when analysed simultaneously by logistic regression analysis. One hundred and fifty-two children with asthma consented to an oesophageal pH study, and an abnormal pH study result (reflux index > 5.0) correlated positively with overweight (OR 4.9, 95% CI 2.2-11.0).

CONCLUSION

The prevalence of symptoms associated with gastro-oesophageal reflux was increased in children with asthma and in overweight children. Overweight and asthma were independently associated with GERD symptoms, and overweight did not explain the higher frequency of GERD in asthma patients.

Extraesophageal associations of gastroesophageal reflux disease in children without neurologic defects

BACKGROUND & AIMS

The potential association between gastroesophageal reflux disease (GERD) and extraesophageal manifestations remains unknown in children without neurological defects. We conducted a large case-control study to examine the association between GERD and several upper and lower respiratory disorders in these children.

METHODS

We identified all patients between 2 and 18 years of age with GERD who were seen at Texas Children's Hospital between 1996 and 2000. Patients seen during the same time period without GERD were randomly selected as controls (4:1 ratio). Patients with mental retardation, cerebral palsy, or congenital esophageal anomalies were excluded. We compared the presence of several predefined upper and lower respiratory disorders in cases and controls.

RESULTS

We identified 1980 patients with GERD and 7920 controls without GERD. Cases and controls were without neurological deficits or congenital esophageal anomalies. Cases were older than controls (9.2 years +/- 4.6 vs. 8.6 +/- 4.9, P < 0.0001), and were more likely to be female (51.2% vs. 47.2%, P = 0.0028) and white (60.2% vs. 41.2%, P < 0.0001). Compared with controls in univariate analyses, cases with GERD had more sinusitis (4.2% vs. 1.4%, P < 0.0001), laryngitis (0.7% vs. 0.2%), asthma (13.2% vs. 6.8%, P < 0.0001), pneumonia (6.3% vs. 2.3%, P < 0.0001), and bronchiectasis (1.0% vs. 0.1%, P < 0.0001). However, otitis media was less common in cases than controls (2.1% vs. 4.6%, P < 0.0001). After adjusting for differences in age, gender, and ethnicity in the regression analyses, GERD remained a significant risk factor for sinusitis (adjusted odds ratio [OR], 2.3; 95% confidence intervals [CI], 1.7-3.2; P < 0.0001), laryngitis (OR, 2.6; CI, 1.2-5.6; P = 0.0228), asthma (OR, 1.9; CI, 1.6-2.3; P < 0.0001), pneumonia (OR, 2.3; CI, 1.8-2.9; P < 0.0001), and bronchiectasis (OR, 2.3; CI, 1.1-4.6; P = 0.0193).

CONCLUSIONS

GERD in children without neurological defects is associated with a several-fold increase in the risk of sinusitis, laryngitis, asthma, pneumonia, and bronchiectasis. Further studies are needed to examine whether a cause-effect relationship exists between GERD and these disorders in children.

Bronchoalveolar lavage and esophageal pH monitoring data in children with "difficult to treat" respiratory symptoms

Gastroesophageal reflux (GER) may be associated with chronic or recurrent asthma-like symptoms secondary to bronchoconstrictor reflexes and/or inhalation of gastric content. The presence of lipid-laden alveolar macrophages has been proposed as an index to establish the degree of gastric aspiration. We evaluated 20 children with "difficult to treat" respiratory symptoms and a clinical history suggestive of GER. All children underwent 24-hr esophageal pH monitoring (pHm) and fiberoptic bronchoscopy with bronchoalveolar lavage (BAL). The amount of lipid per single macrophage was determined by a semiquantitative method, using fluorescence microscopy to detect Nile-Red-stained BAL cells and calculating a lipid-laden macrophage index (LLMI). Eleven children had positive pHm recordings, suggesting the presence of GER (pH-positive patients), and 9 had negative pHm records (pH-negative patients). The pH-positive patients had higher percentages of neutrophils and higher LLMI than the pH-negative children (P < 0.05). There were no correlations between the pHm records and either % BAL neutrophils or LLMI in pH-positive or pH-negative patients (P > 0.05; each correlation). In contrast, a single correlation was found between % BAL neuytrophils and LLMI, both in the pH-positive and in the pH-negative patients (r = 0.72, P = 0.02 and r = 0.71, P = 0.04, respectively). These data demonstrate that a significant proportion of pH-positive patients with respiratory symptoms have BAL abnormalities that suggest airway inflammation and gastric content aspiration. However, the intensity of GER as indicated by pH monitoring does not correspond with BAL data in all patients.

Airway reactivity following repeated milk aspiration in rabbits

Asthma and gastroesophageal reflux (GER) are commonly associated disorders. Microaspiration is one possible link between these processes. The purpose of this study was to assess methacholine reactivity following repeated small-volume aspiration such as may occur with GER. This was also correlated with airway cytology. Five weekly intratracheal instillations of either milk (N = 8) or saline sham controls (N = 7) in volumes of 0.25 mL/kg were performed in anesthetized rabbits. Transpulmonary pressure, flow, tidal volume, central airways resistance, and dynamic lung compliance were measured in anesthetized and paralyzed animals at baseline, after 2 and 5 weeks of instillation, and 3 weeks after the last instillation. Doubling concentrations of methacholine were given until a 50% or greater increase in resistance occurred (PC50R). Bronchial washings for cytological evaluation were performed after the physiologic measurements and before each instillation. There were no significant differences in airway reactivity between baseline and all subsequent observation points within each of the two groups. However, methacholine responsiveness was significantly higher in the milk group before the final instillation (PC50R = 5.84 vs. 12.97 mg/mL, P = 0.03) and at recovery (PC50R = 6.40 vs. 10.56 mg/mL, P = 0.047) when compared to saline controls. This was associated with a higher neutrophil percentage (P = 0.01) at 5 weeks, and eosinophil percentage (P = 0.05) at recovery in the bronchial wash specimens from the milk group. These results show that repeated small-volume aspiration of milk in rabbits causes persistent inflammation and is associated with greater airway reactivity when compared to sham controls. This inflammation was accompanied by either increased neutrophils or eosinophils in bronchial lavage specimens. These findings lend support to a possible role of microaspiration in association with increased airway reactivity in patients with GER.

Diagnosis and treatment of gastroesophageal reflux in children and adolescents with severe asthma

BACKGROUND

The ability of gastroesophageal reflux disease to provoke asthma is controversial. Recent reports have suggested that reflux to the proximal esophagus may be especially likely to aggravate asthma, but the prevalence of proximal reflux in children and adolescents is poorly documented. It is also unclear how sensitive and specific the commonly used tests of reflux, barium swallow, and scintiscan are compared with pH probe studies in young patients. There is limited information on the effectiveness of the combination of H2 blockers and prokinetic agents in controlling reflux in children.

OBJECTIVE

There were three objectives in this study: (1) to determine the prevalence of both proximal and distal gastroesophageal reflux in asthmatic children and adolescents; (2) to determine the sensitivity, specificity, positive and negative predictive values of barium swallow and scintiscan studies; and (3) to determine the effectiveness of standard antireflux pharmacotherapy.

METHODS

A 24-hour, 2-channel pH probe study was carried out in 79 asthmatic children aged 2 to 17 years. The prevalence of abnormal proximal and distal gastroesophageal reflux was calculated from the findings. In 63 of these patients, barium swallow and Technetium99 scintiscan were carried out and the findings used to calculate the sensitivity, specificity, positive and negative predictive value of these studies relative to pH probe. In 11 subjects a follow-up, 24-hour pH probe was carried out after at least 3 weeks of therapy with an H2 blocker and prokinetic agent to determine the efficacy of therapy.

RESULTS

There was abnormal proximal esophageal reflux in 64.5% of subjects and abnormal distal reflux in 73.4%. The sensitivity, specificity, positive and negative predictive values of barium swallow were 46.1%, 83.3%, 82% and 51%, respectively. Those of scintiscan were 15%, 72.7%, 50% and 32%, respectively. Of 11 subjects studied by repeat pH probe, 10 had persistent abnormal reflux.

CONCLUSION

Abnormal reflux into the proximal esophagus occurs in the majority of asthmatic children with difficult-to-control disease. The barium swallow and scintiscan compare poorly with pH probe in diagnosing reflux. Treatment of reflux with recommended does of H2 blockers and prokinetic agents has a high failure rate, and follow-up studies are essential.

Chronic night cough and asthma severity in children with stable asthma

The relationship between night cough and other indices of asthma severity was studied in 21 children with clinically stable asthma and persistent night cough. Overnight cough was quantified and related to symptom scores, oxygen saturation (SaO2) during sleep, evening and morning peak flow recordings and daytime tests of lung function. In the index group the median number of coughing episodes was 23 (range 1-158). Only 4 children had counts of < 10 overnight, similar to the comparison group of 12 children all of whom had counts of < 10. There was a trend towards the association of overnight cough with reduced evening peak flow (r = -0.407, P = 0.07) and reduced SaO2 (r = -0.36, P = 0.10). Abnormalities in daytime tests of lung function were observed in 13 children. There was no relationship between night cough and daytime indices of lung function abnormality although children with more severe daytime abnormalities also had significant night cough. Conversely, five children with chronic night cough had normal daytime function. Conclusion. Night-time cough in children with asthma is not simply a reflection of daytime lung function status, whereas, overnight SaO2 correlates well. Other factors need to be explored to explain the variability of night-time cough in these children.

Gastro-oesophageal reflux and chronic respiratory disease in infants and children: treatment with cisapride

Gastro-oesophageal reflux (GOR) has been implicated in such clinical phenomena as aspiration pneumonia, bronchospasm or wheezing, apnea, stridor, and hoarseness. Various tests have been used as an aid to diagnosing patients with chronic respiratory disease where GOR is a causal factor. Different forms of conservative treatment have been tried for GOR, including cisapride. Several studies have evaluated its effect on the pH profile and respiratory symptoms in patients with chronic respiratory disease and have demonstrated improvement of nocturnal wheezing, cough, and irritability. Our experience with cisapride is positive in children with GOR. Patients refractory to medical treatment have been surgically treated with good results.

Gastro-oesophageal reflux and oesophageal dysfunction in children and adolescents with brain damage

The prevalence of pathological gastro-oesophageal reflux (GOR) and oesophageal dysfunction (OD) was investigated in 32 children, 0.7-19 years of age (mean 11.2 years), with brain damage, mainly severe cerebral palsy and tetraplegia. They underwent 24-h pH monitoring in the distal oesophagus and oesophageal manometry. In addition, radiological examination of the oesophagus, chest radiography, blood counts and blood tests for iron deficiency were carried out. Fifteen (47%) patients had mild pathological acid reflux, 5 (16%) had moderately severe and 5 (16%) severe acid GOR. Seven of 32 (22%) patients had no pathological GOR. Ten patients had abnormal manometry findings and 9 had a pathological radiological oesophagus examination. Three patients had radiographic lung consolidations. Thirteen patients had iron deficiency and 5 were anaemic. Two patients with severe acid reflux have died, presumably from aspiration-induced pneumonia. Findings of OD and GOR are frequent in children with brain damage and are related to significant complications, including fatal course.

Wrong-way swallowing as a possible cause of bronchitis in patients with gastroesophageal reflux disease

A new theory was tested that swallowing the wrong way is the cause of the strong correlation between bronchial symptoms and gastroesophageal reflux disease (GERD). One hundred and nineteen patients who were operated on for hiatal hernia and GERD were compared with 89 patients treated with the proton pump inhibitor omeprazole concerning bronchial symptoms before and after treatment. Both groups had a frequency of cough of 34% before treatment. Omeprazole did not give any significant relief of cough, whereas patients who were operated on with fundoplication and crural repair showed a highly significant reduction of cough and bronchitis. It is believed that the distal anchoring of the longitudinal esophageal muscle by surgery improves esophageal transit and restores the delicate coordination in the swallowing centre between deglutition, the opening of the upper esophageal sphincter, and the epiglottic closure of the laryngeal entrance. It is concluded that the main reason for chronic bronchitis in patients with GERD is intermittent aspiration due to partial mis-swallowing.

Gastro-oesophageal reflux and severity of pulmonary disease in cystic fibrosis

The correlation between oesophageal dysfunction (OD), pathologic gastro-oesophageal reflux (GOR), and severity of pulmonary disease was studied in 12 patients with cystic fibrosis (CF). They were interviewed about symptoms of OD and underwent 24-h pH recording in the oesophagus, oesophageal manometry combined with reflux provocation tests, the acid perfusion test, the acid clearance test, lung function tests, and scoring of the chest radiograph. Six of the 12 patients reported symptoms of OD. Abnormal GOR, as shown by 24-h pH monitoring of the oesophagus, was found in eight of them. Altogether 9 of the 12 participants had at least one pathologic oesophagus test result. Results of radiologic examinations of the oesophagus, performed in six patients, were pathologic. The four patients with the best chest radiograph scores and the best lung function had significantly less signs and symptoms of OD and GOR than the other eight patients. We conclude that OD, GOR, and pulmonary disease covariate in CF.

Bronchial asthma and acid reflux into the distal and proximal oesophagus

The prevalence of pathological gastro-oesophageal reflux in children and adolescents with asthma was studied by 24 hour two level oesophageal pH monitoring in 42 subjects aged 9-20 years with moderate or severe bronchial asthma. The importance of oesophagobronchial nerve reflexes and of aspiration of gastric acid as triggers in asthma was assessed by studying whether episodes of reflux into the distal and into the proximal oesophagus were followed by asthma attacks. Twenty-one subjects (50%) had a pathological total reflux time in the distal oesophagus and six (16%) in the proximal oesophagus. Nine patients had pathological gastro-oesophageal reflux into the distal oesophagus together with symptoms of asthma during the day on which the recording took place. In three of them the episodes of asthma symptoms were significantly correlated with preceding episodes of reflux into the distal oesophagus, and in one subject to reflux into the proximal oesophagus. We conclude that pathological gastro-oesophageal reflux is common in children and adolescents with asthma, but it seems to provoke symptoms of asthma in only a few. Symptoms of asthma were more often elicited by exposure of the distal oesophagus to gastric acid, possibly by a vagal reflex, than by aspiration of gastric juice.