Special features of asthma in children

Does a 'reverse' atopic march exist?

The classical description of the atopic march usually refers to the progression from atopic dermatitis towards asthma, but this pathway has been questioned. We assessed in a prospective observation the possible onset of atopic dermatitis in children with asthma alone at baseline, and evaluated retrospectively their characteristics. Seven hundred and forty-five children (360 male, 6-9 years of age) with asthma alone, without food allergy or atopic dermatitis, were followed-up with regular visits for 9 years. 692 children completed the 9-year observation, and 20% of them were found to have developed atopic dermatitis at 9 years. Comparing retrospectively the children who developed AD with the remaining, no significant difference existed at baseline concerning the demographic characteristics and family history. There was a significantly higher proportion ( chi2 = 0.01) of subjects with single sensitization to mites and a significantly lower proportion of polysensitized subjects ( chi2 = 0.01) within the children who developed AD. Sensitization to foods appeared in 9% of children who developed AD and in 3.8% in the other children (NS). According to these observations, the development of a particular allergic disease does not necessarily follow the classical paradigm of the atopic march.

Gastroesophageal reflux disease in children with asthma: treatment implications

An association between asthma and gastroesophageal reflux disease (GERD) has long been recognized both mechanistically and epidemiologically. The clinical relevance of this interplay continues to be explored, with special interest given to the role of GERD in the worsening of asthma. The effect of GERD is most frequently contemplated in patients with asthma that is difficult to control. Medical and surgical anti-reflux trials attempting to alter asthma symptoms have reported mixed but generally underwhelming results, although asthma symptom scores are generally improved following effective treatment of GERD. Many of the pharmaceutical studies can be criticised for having too short a duration or for likely incomplete acid suppression. Few trials have specifically studied pediatric populations. Because GERD is a common condition, particularly in young children, the role reflux plays in the worsening of asthma symptoms and the potential benefit on asthma of anti-reflux therapy warrants further exploration. Whether or not treating symptomatic GERD reduces the symptoms and severity of asthma in children, GERD coexisting with asthma should be aggressively treated. GERD symptoms in most patients with or without asthma can be controlled medically with continuous use of proton pump inhibitors such as omeprazole and lansoprazole and to a lesser extent by histamine H(2) receptor antagonists such as famotidine and cimetidine.

The role of age at asthma diagnosis in the development of triggers of asthma episodes

This study examined the relationship of age at asthma diagnosis to the subsequent impacts of 12 common asthma triggers, which we classified as either mainly physically based or strongly psychosocially mediated. The physically based triggers were air pollution, cigarette smoke, high humidity, high/low environmental temperature, allergy problems, respiratory infection, physical activity, and nighttime hours; the psychosocially mediated triggers were stress or worry, anger, excitement, and laughter. Data were collected with questionnaires from families with asthmatic children (n=115), 2 to 20 years of age, as part of a larger study of biological and psychosocial factors in asthma and other illnesses. Using parents' reports, we classified the children as early-diagnosed (before age 2) or later-diagnosed (at or after 2) for asthma and compared these groups, separated by gender, in 2 x 2 multivariate analyses. The impacts of all four psychosocially mediated triggers on asthma attacks were significantly greater for the later-diagnosed children than the early-diagnosed children. No age of diagnosis differences were found for any of the physically based triggers, and no gender or interaction effects were found for either type of trigger.

Tests of the relationship between children's temperament and asthma and of the reliability and validity of the Brief Scale of Temperament

Two studies are reported. One examined the reliability and validity of a brief scale to measure children's temperament; the other tested the relationship of early temperament and the development of asthma. In Study 1, principal caretakers of 46 4- to 7-year-olds, usually the mothers, filled out questionnaires containing the Brief Scale of Temperament (BST) and the Behavioral Style Questionnaire. The caretakers did this twice, about 1 week apart. The first time the children's recent temperament was assessed, and the second time past (> 1 year) temperament was assessed. Internal consistency and correlational analyses revealed substantial reliability and validity for BST assessments of recent and past temperament. Study 2 incorporated the BST in a large-scale survey of 325 families, with parents providing data on their children's asthma and temperament. BST assessments of early (past) temperament were made retrospectively regarding the child's first few years. Comparisons of early temperament revealed no differences between children who developed asthma and those who did not in their overall scores on the BST or for any of the temperament characteristics it measures. In addition, correlational analyses of data for asthmatics showed that early temperament was not related to ratings of the severity of the asthma condition the children developed or the impacts of any of 12 specific asthma triggers, including any involving emotional states, such as stress or worry.

Relationships among respiratory infections, triggers of attacks, and asthma severity in children

The present study of asthmatic children examined relationships among the frequencies of prior respiratory infections (i.e., those prior to the development of asthma) and recent (past year) respiratory infections, asthma severity, and the impacts of 12 common asthma triggers: air pollution, allergy problems, anger, cigarette smoke, excitement, high humidity, high or low environmental temperature, laughter, nighttime hours, physical activity, respiratory infection, and stress or worry. Data on these variables were obtained through a survey in which 325 families completed questionnaires; 121 families had asthmatic children who were 2-20 years of age. Pearson correlational analyses revealed many significant positive correlations: The frequencies of prior and recent infections were correlated. The frequency of prior infections was correlated with the impacts of all asthma triggers except allergy problems, but the frequency of recent infections was correlated only with the impacts of air pollution, cigarette smoke, respiratory infection, and nighttime hours as triggers of asthma attacks. Asthma severity was correlated with the frequencies of prior and recent respiratory infections and with the impact of respiratory infection as an asthma trigger.

Age and the impacts of triggers in childhood asthma

This study examined the relationships among age (2-20 years) and the impacts of 12 common triggers in episodes of childhood asthma. The triggers were: air pollution, allergy problems, cigarette smoke, stress or worry, anger, excitement, laughter, high/low environmental temperature, high humidity, respiratory infection, nighttime hours, and physical activity. Data were analyzed from families with asthmatic children (n = 119) as part of a larger study of biological and psychosocial factors in asthma and other illnesses. Positive correlations were found for age and the trigger impacts of allergy problems (p = 0.025) and physical activity (p = 0.004); negative correlations were found for age and the trigger impacts of nighttime hours (p = 0.002) and respiratory infection (p = 0.002). Age was also negatively correlated with the frequency of recent respiratory infections (p = 0.000) and positively correlated with the intensity of hay fever episodes (p = 0.047). These findings indicate that as children with asthma get older, their asthma episodes are more likely to be influenced by allergy problems and physical activity, and less likely to be associated with nighttime hours and respiratory infections.

Development of a clinical asthma score for use in hospitalized children between 1 and 5 years of age

The objective of this study was to develop a clinical asthma score (CAS) for use in hospitalized children between 1 and 5 years of age. Formal approaches to item selection and reduction, reliability, discriminatory power, validity, and responsiveness were used. The final CAS consisted of five clinical characteristics: respiratory rate, wheezing, indrawing, observed dyspnea, and inspiratory-to-expiratory ratio. Interrater reliability was high (weighted kappa = 0.82), and the CAS was discriminatory (Ferguson's delta = 0.92). The CAS was valid, with a strong correlation with length of hospital stay (Spearman's correlation = 0.47, p < 0.05) and drug dosing interval (Spearman's correlation = -0.58, p < 0.01). The CAS was responsive, with a significant change in CAS from admission to discharge (Wilcoxon signed rank test, p < 0.01). This score, for use in hospitalized preschool children, is reliable, discriminatory, valid, and responsive.

Acute asthma: treatment and outcome of 2000 consecutive pediatric emergency room visits in Doha, Qatar

The case files of 2000 asthma episodes seen in our pediatric emergency room (PER) over a 2-month period were reviewed. Patients included 1429 males and 571 females with 66.2% < 48 months old. More than 60% of patients had been symptomatic for <24 hr and 88.5% had tried inhaled beta2-agonist before coming to the PER. In the PER, 57% responded to a single salbutamol aerosol and 35.5% responded to a combination of 2-3 salbutamol, IV hydrocortisone, and aminophylline drip < or = 6 hr. Only 7.5% were admitted to the hospital. Of the admitted patients, 82% had been symptomatic for > 24 hr and 60.6% were <4 years old.

Genetic factors in the presence, severity, and triggers of asthma

The role of heredity in the presence of asthma, severity of the condition, and impact of 12 specific triggers of attacks was investigated. Health surveys containing questions about children's asthma characteristics were completed by 325 families with twin children across the United States. Data for 39 monozygotic twin pairs and 55 same sex dizygotic twin pairs who were between 2 and 20 years of age and had asthma present in at least one member of each pair were received and analysed. Results revealed higher concordance for the presence of asthma among monozygotic (58.97%; n = 23) than dizygotic twins (23.64%; n = 13). Further analyses were restricted to data from the concordant monozygotic and dizygotic twin pairs. Asthma severity (the product of attack frequency and intensity ratings) was significantly correlated for monozygotic pairs but not for dizygotic pairs, and this difference in monozygotic and dizygotic severity correlations was significant. Also, monozygotic twins showed significantly higher correlations than dizygotic twins for the impacts of two asthma triggers: respiratory infection and physical activity. These results indicate a role of heredity in the presence of asthma and suggest that genetic factors may also affect the severity of children's asthma condition and the impact of respiratory infection and physical exertion as asthma triggers.

The prevalence of childhood asthma in Costa Rica

The prevalence of asthma in children between the ages of 5 and 17 years in Costa Rica was determined using a large sample (n = 2682). The definition of asthma was based on a combination of a physician's diagnosis and a symptom score, using information from a questionnaire given to the parents. An overall asthma prevalence as high as 23.4% was found. Sex, age, urban/rural location, or rain precipitation did not show any association with the diagnosis of asthma. The presence of smokers in the home was found to be an important risk factor (odds ratio = 1.6). Another identified risk factor was a high yearly average outside temperature, i.e. above 25 degrees C (odds ratio = 1.8). Furthermore, the proportion of children with more than four upper respiratory infections during the preceding year was found to be significantly increased in children with asthma (odds ratio = 4.3). The non-asthma group seemed to use equal amounts of drugs for the treatment of asthma as the asthma group. For a country like Costa Rica with limited economic resources the current work indicates two important issues for consideration in the future; firstly, to try to define the cause(s) of asthma and secondly, to continuously inform the physicians about the best way of diagnosing and treating asthmatic patients to ensure optimal handling of this large patient group.

Clinical scores for acute asthma in pre-school children. A review of the literature

The objective of this paper was to evaluate the applicability in research and clinical practice of clinical scores for acute asthma in pre-school children. All instruments were reviewed according to a standardized set of criteria: purpose of the score, suitability for use in children, inter-observer agreement, validity and responsiveness. A Medline literature research resulted in 16 different clinical asthma scores, which have been developed to assess the severity of acute asthma, to predict the outcome of an attack, or to evaluate the response to treatment. Most asthma scores could be easily obtained in children. Three scores have been modified to facilitate application in a younger age-category. Inter-observer agreement has received little attention, although all scores contained items that require subjective judgement. The predictive validity was insufficient to justify the application of clinical scores as a decision rule for the admission or discharge of children with acute asthma. Asthma scores seem to be useful for assessing the severity of an attack and evaluating the response to therapy, but as yet there is insufficient information on the performance of the scores to justify a preference. Wheezing and retractions appear to be important items of any useful score for acute asthma.

Trends in physician-diagnosed asthma prevalence in Manitoba between 1980 and 1990

We attempted to assess recent changes in the prevalence of physician-diagnosed asthma and the possible influence of diagnostic exchange on these trends. The routinely collected data of the provincial Health Insurance Plan (physicians' claims) were used to determine the annual prevalence of physician-diagnosed asthma in Manitoba. Results indicate that the prevalence of physician-diagnosed asthma increased for all age groups in both male and female subjects between 1980 and 1990. The average increases were the highest in the age group 5 to 14 years for both sexes. The average increases varied with age and there were significant differences between the two sexes. There was evidence of increasing diagnostic exchange, that is, a tendency to label patients with asthma instead of alternative diagnoses. This was particularly prominent in those younger than 35 years of age. However, the increased prevalence of physician-diagnosed asthma, even for the younger population, cannot be fully explained by diagnostic exchange.

Prehospital administration of inhaled metaproterenol

STUDY OBJECTIVES

We conducted a study of the prehospital use of inhaled metaproterenol. DESIGN, SETTING, TYPE OF PARTICIPANTS, AND INTERVENTIONS: Advanced life support (ALS) providers were trained with a standardized curriculum to identify patients likely to benefit from prehospital inhaled metaproterenol administration. Unit doses of metaproterenol were used in a small-volume nebulizer. We prospectively included 122 patients in an initial study (71 men; age, 63 +/- 19 years) to evaluate the safety and effectiveness of metaproterenol in the field, and 150 patients (including the original 122) in an additional study to evaluate patient selection criteria.

MEASUREMENTS AND MAIN RESULTS

The treatments resulted in an increase in peak flows, a decrease in respiratory rates, and no change in heart rates. In 62% of patients, the increase in peak flow exceeded 15%. Wheezing improved in 59% of the patients, worsened in 4%, and did not change in the remainder. Air entry by auscultation improved subjectively in 59% of patients. Mild tremor occurred in 8% of patients, moderate tremor occurred in 1%, and no tremor occurred in the remainder. Significant dysrhythmias did not occur.

CONCLUSIONS

ALS providers correctly identified patients for this therapy. No technical problems were encountered in the field with this treatment approach. We conclude that ALS providers can be taught to identify patients likely to benefit from inhaled metaproterenol, that inhaled metaproterenol can be administered in the field, and that metaproterenol is both safe and effective when used in the prehospital setting.

Asthma in children: emergency management

We review the pathophysiological alterations at work in asthma and outline pharmacological agents that are available for emergency therapeutic intervention, offering some general principles for management. A combined overview of predictors of outcome in asthmatic episodes in children also is presented.