ABSTRACT
Nocturnal exacerbations of bronchial asthma are very common and disturbing signs with serious consequences on patient's quality of life. The exact mechanism of these exacerbations is not known but inflammatory mediators may play an important role. To study the role of leukotriene E[4] [LTE[4]] in the pathogenesis of nocturnal exacerbations of bronchial asthma. The study was conducted on 50 asthmatic children who used to attend the outpatient clinics of the Pediatric and Chest Departments of Tanta University Hospital. Their ages ranged 8-14 years. The study was carried out over 10 months from October 1, 2000 to July 31, 2001. They were classified into two groups. Group A included 25 asthmatic children without nocturnal symptoms, and group B comprised 25 children who used to have nocturnal asthma exacerbations. Twenty non-asthmatic children of comparable ages were included in the study as controls. All of the children were subjected to full history taking, clinical examination, pulmonary function tests [PFTs], methacholine bronchial challenge test, and measurement of LTE[4] in urine. Values of morning drop of peak expiratory flow [PEFR] in children with nocturnal symptoms [Group B] was significantly higher than those in the asthmatic children without nocturnal exacerbations [Group A] [P<0.05]. The PC[20] FEV[1] was significantly lower in group B than in group A [P<0.05]. Urinary LTE4 levels were found to be significantly higher in group B than in group A [P<0.05]. In asthmatic children with nocturnal exacerbations [group B], urinary LTE[4] levels were found significantly higher at night more than at day hours [P<0.05]. Also, in this same group B, there were significant positive correlations between urinary LTE[4] levels and morning drop in PEFR values and significant negative correlation between urinary LTE[4] levels and PC[20] FEV[1] [P<0.05]. There was no significant difference in urinary LTE[4] levels between atopic and non-atopic asthmatic children. Measurement of urinary LTE[4] levels may represent a non-invasive method for assessment of airway inflammation and for predicting the outcome of nocturnal exacerbations that disturb the life of asthmatic children