Dennis Gurwitz

Increased incidence of bronchial reactivity in children with a history of bronchiolitis

To assess bronchial reactivity in children who have had bronchiolitis, we studied 48 children by challenging them with methacholine nine or ten years after admission to hospital with bronchiolitis. Pulmonary function was also evaluated. Fifty-seven percent of children studied had bronchial hyperreactivity. Thirty-three percent of first-degree relatives of those with a positive MCH challenge had a positive response. There was a significant correlation between the occurrence of a positive MCH challenge and a history of recurrent bronchiolitis. Pulmonary function tests demonstrated lower flow rates in the positive responders. Fourteen children had a history of asthma or wheezing, but this did not appear to be severe or frequent, and few required long-term therapy. There appears to be a strong genetic component in the prevalence of bronchial reactivity in these children. Bronchial hyperreactivity may be a risk factor in the development of COPD.

Perspectives in Cystic Fibrosis

Sex differences, age at diagnosis, type and severity of symptoms at presentation, pulmonary function, and radiologic findings are prognostic factors that enable the clinician to place patients in various risk groups. The definition and characteristics of these groups will aid in the assessment, counseling, and follow-up of patients with cystic fibrosis.

Corticosteroids in status asthmaticus

Nineteen children who were not steroid dependent and were hospitalized in status asthmaticus were studied to evaluate the effect of corticosteroids. They were randomized into two groups. Each group received salbutamol inhalations and intravenous aminophylline therapy. One group received 7 mg/kg hydrocortisone intravenously every six hours; the other group served as a control. Each group showed significant improvement in clinical score and peak expiratory flow rate after 36 hours; there was no statistical difference in the degree of improvement. Six of ten steroid-treated children and six of nine controls achieved a PEFR of 50% predicted by 36 hours. The response to inhaled salbutamol was similar in each group. The results show that in the first 36 hours of therapy, corticosteroids have no additive effect on the bronchodilator response of aminophylline and salbutamol and do not hasten the recovery of nonsteroid-dependent children in status asthmaticus. Although the results show that an inhaled sympathomimetic drug is beneficial in status asthmaticus, corticosteroid therapy does not increase the responsiveness of the airways to these agents.

1187 PULMONARY FUNCTION ABNORMALITIES IN ASYMPTOMATIC CHILDREN FOLLOWING HYDROCARBON PNEUMONITIS

To assess the effect of hydrocarbon pneumonitis on the developing lung we studied the pulmonary function of seventeen asymptomatic subjects, eight to fourteen years after the initial insult. Fourteen of the 17 subjects (82%) had one or more pulmonary function abnormalities, the most frequent being a high volume of isoflow. Volume of isoflow, the ratio of residual volume to total lung capacity, slope of Phase III, flow rates at 50 and 25% of vital capacity and 60% of the total lung capacity, one second forced expiratory volume and maximum mid expiratory flow rate differed significantly (p < .05) from age and height matched controls. Closing volume and closing capacity were not significantly different. The data show that residual abnormalities are present following hydrocarbon pneumonitis. This could be explained on the basis of small airway obstruction and/or loss of elastic recoil and are similar to the earliest changes seen in smokers and adult patients with chronic obstructive lung disease. These children may be at higher risk for the development of chronic lung disease in adulthood when exposed to exogenous factors such as air pollution or smoking.

1197 CORTICOSTEROIDS IN STATUS ASTHMATICUS

The role of corticosteroids in status asthmaticus (SA) is controversial. To evaluate their effect thirteen children (ages 8-14 years) hospitalized in status asthmaticus were randomly assigned to one of two treatment groups. Both groups received oxygen, .01cc/kg salbutamol aerosol Inhalation every 4 hours and intravenous aminophylline. Six of the 13 children were given hydrocortisone 7 mg./kg. six hourly intravenously as well. Clinical score, arterial blood gases and peak expiratory flow rates (PEFR) at the time of admission were similiar in the steroid treated and control groups. Peak and trough serum theophylline levels were also similiar in the two groups. After 24 hours of therapy, both groups showed significant improvement in clinical score and PEFR. However, the degree of improvement in the steroid treated and control groups was not statistically different. One child in each group failed to show any improvement in the first 24 hours of therapy. The mean percentage increase in PEFR in the first 24 hours with each dose of inhaled salbutamol was 19.5±15.7 in the steroid treated group and 22.8±8.2 in the control group. We conclude that in the first 24 hours corticosteroids do not hasten the recovery of children in SA. Although the results show that inhaled B-2 agonists are beneficial in SA, corticosteroids do not increase the responsiveness of the bronchial smooth muscle to these agents.