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Longitudinal study of bronchial hyperreactivity in preschool children with bronchial asthma
Y Adachi1, G Murakami, M Matsuno
1Department of Pediatrics, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Insights
Bronchial hyperreactivity in young asthmatic children can worsen over time, especially in severe cases. Family history of asthma may influence this condition, indicating complex congenital and acquired factors.
Area of Science:
- Pediatric Pulmonology
- Allergy and Immunology
- Respiratory Medicine
Background:
- Bronchial hyperreactivity (BHR) is a hallmark of asthma.
- Understanding BHR changes in young children is crucial for effective management.
- Factors influencing BHR progression in pediatric asthma require further investigation.
Purpose of the Study:
- To evaluate changes in BHR in asthmatic children aged 4-6 years over 2-3 years.
- To identify potential factors influencing these changes in bronchial hyperreactivity.
- To explore the relationship between asthma severity, clinical course, and BHR.
Main Methods:
- Longitudinal study of 40 asthmatic children (4-6 years old).
- Histamine inhalation tests (HIT) to assess bronchial hyperreactivity (BHR).
- Measurement of transcutaneous oxygen pressure to evaluate BHR.
Main Results:
- Respiratory threshold to histamine (RT-Hist) was significantly lower in severely asthmatic children at the final test.
- RT-Hist significantly decreased in children whose asthma worsened.
- No improvement in RT-Hist was observed in children with favorable clinical courses.
- A family history of asthma was more prevalent in the high BHR responder group.
Conclusions:
- Bronchial hyperreactivity in young asthmatic children is dynamic and influenced by multiple factors.
- Asthma severity and clinical course impact BHR over time.
- Congenital (e.g., family history of asthma) and acquired factors likely contribute to BHR development and progression.
Abstract:
Forty asthmatic children aged 4 to 6 years performed histamine inhalation tests over 2 to 3 years. We used a previously reported method for examining bronchial hyperreactivity; measuring the transcutaneous oxygen pressure to evaluate whether bronchial hyperreactivity in younger children with bronchial asthma changed, and which potential factors affected changes in bronchial hyperreactivity. Although there was no significant relationship between the severity of asthma and respiratory threshold to histamine (RT-Hist) at the initial test, RT-Hist results in the severely asthmatic group were significantly lower than those of the remission and mild groups at the final test (P less than .01), respectively. RT-Hist significantly decreased in only the group whose asthma worsened (P less than .05). In the remission and improvement groups, RT-Hist did not improve despite their favorable clinical courses. When divided into two subgroups according to the extent of their RT-Hist, a high responder group had significantly more subjects who family histories of asthma than the low-responder group (P less than .05). There was no difference, however, in family history of allergic diseases between the two groups. We conclude that bronchial hyperreactivity in younger asthmatic children is influenced by multiple factors that may be congenital or acquired.