525 Bronchial Hyperresponsiveness in Children with Suggestive Asthma Symptoms

Abstract

BackgroundTo describe the accuracy of bronchial challenge tests (methacholine and manitol) to measure bronchial hyperresponsiveness in a group of pediatric patients with suggestive symptoms of asthma.MethodsWe selected 27 patients who attended consecutively to our outpatient clinic complaining of 1 or 2 symptoms of asthma. They showed a normal baseline spirometry and a negative bronchodilator test. All of them underwent unspecific bronchial provocation challenges. Methacholine was performed using the tidal volumen technique and a PC20 ≤ 8 mg/mL was considered positive. Dry-powder mannitol (Osmohale TM) was administered according to the manufacturer's recommendations and the challenge was considered positive if a PD15 ≤ 635 mg resulted. We performed both tests with an interval of at least 1 week. Asthma drugs were avoided during the 2 weeks previous to every challenge. Skin prick tests (SPT) to the most common aeroallergens were also performed.ResultsMean age was 9 (ranged 7–15) years, 18 (66.6%) children were male. Symptoms referred were: 14 (51.8%) cough, 10 (37%) seasonal cough or shortness of breath, 5 (18.51%) cough or shortness of breath due to physical exercise and 1 (3.7%) cough or wheezing related to respiratory infections. SPT were positive in 59.2% of the children. Eighteen (66.6%) out of 27 patients had bronchial hyperresponsiveness, and 10 (37.03%) were non atopic. All patients with a positive response to manitol showed also positivity to methacholine. Mean methacoline PC20 among responders was 0.64 ± 4.08 mg/mL. Manitol was performed in 16 children, and resulted positive in 8 cases (50%) with a mean PD15 of 146.8 ± 246.49 mg. In 2 (25%) out of 8 patients with negative manitol resulted a positive methacholine.ConclusionsMethacholine and manitol challenge tests detected bronchial hyperresponsiveness in more than a half of the studied children with suggestive asthma symptoms. Methacoline was more sensitive than manitol.