Painful episodes in children with sickle cell disease and asthma are temporally associated with respiratory symptoms

Background: Little is known about the temporal relationship between an asthma exacerbation and a painful episode in a child with sickle cell disease (SCD). We tested the hypothesis that respiratory symptoms either immediately precede or occur concomitantly with painful episodes more frequently in children with SCD and asthma when compared with children with SCD without asthma. Methods: A cohort study was conducted. As part of standard care, the primary hematologist referred all children with SCD for evaluation by a pulmonologist. The definition of asthma was based on the National Heart Lung and Blood Institute's guidelines. All painful episodes during a 25-month sampling frame were reviewed. Events that were diagnosed as asthma exacerbations were excluded from analysis. Respiratory symptoms (cough, wheeze, tachypnea, retractions, or grunting) were included if they occurred up to 96 hours before a painful episode. Results: A total of 74 children were evaluated for a painful episode. Of these patients, 36 were diagnosed with asthma (mean age 9.8 y; range 2.4 to 19.4) and 38 were determined not to have asthma (mean age, 9.8 y; range 2.4 to 19.5). Among the children with pain and asthma, the odds ratio of having antecedent or concurrent respiratory symptoms was 4.9 (95% confidence intervals, 2.2-10.7) when compared with children with pain and without asthma. Conclusions: In children with both SCD and asthma, respiratory symptoms are a risk factor for painful episodes within 96 hours.