Wheeze is an unreliable endpoint for bronchial methacholine challenges in preschool children.

BACKGROUND: Onset of wheeze is the endpoint often used in the determination of a positive bronchial challenge test (BCT) in young children who cannot perform spirometry. We sought to assess several clinical endpoints at the time of a positive BCT in young children with recurrent wheeze compared to findings in school-aged children with asthma. METHODS: Positive BCT was defined in: (1) preschool children (n = 22) as either persistent cough, wheeze, fall in oxygen saturation (SpO2 ) of ≥5%, or ≥50% increase in respiratory rate (RR) from baseline; and (2) school-aged children (n = 22) as the concentration of methacholine (MCh) required to elicit a 20% decline in FEV1 (PC20 ). RESULTS: All preschool children (mean age 3.4 years) had a positive BCT (median provocative MCh concentration 1.25 mg/ml [IQR, 0.62, 1.25]). Twenty (91%) school-aged children (mean age 11.3 years) had a positive BCT (median PC20 1.25 mg/ml [IQR, 0.55, 2.5]). At the time of the positive BCT, the mean fall in SpO2 (6.9% vs. 3.8%; p = .001) and the mean % increase in RR (61% vs. 22%; p < .001) were greater among preschool-aged than among school-aged children. A minority of children developed wheeze at time of positive BCT (23% preschool- vs. 15% school-aged children; p = .5). CONCLUSIONS: The use of wheeze as an endpoint for BCT in preschool children is unreliable, as it rarely occurs. The use of clinical endpoints, such as ≥25% increase in RR or fall in SpO2 of ≥3%, captured all of our positive BCT in preschool children, while minimizing undue respiratory distress.

Corticosteroid therapy in asthma: predictors of responsiveness.

Variable responses to corticosteroids are seen in a multitude of disease states including asthma, a disease in which these anti-inflammatory medications play a central role in both acute and chronic management. Clinical factors associated with steroid insensitivity, strategies for managing patients with steroid insensitivity, and underlying molecular mechanisms responsible for variable responses to corticosteroids are described.

Asthma adherence and the athlete.

Although much has been written on the topic of adherence (also known as compliance) in asthma, little is known about adherence in the asthmatic athlete. There are shared reasons for poor adherence to treatment among athletes of varying ages and levels of competition. The Shared Decision-Making model is considered to be the optimal approach to enhancing adherence among all patients with chronic disease but is particularly well applied to athletes with asthma. This article discusses athlete-related, physician-related, and treatment-related barriers to adherence, as well as how to overcome these barriers to promote optimal disease management. Special considerations for the elite or professional athlete are also addressed.