Nocturnal asthma

Nocturnal asthma has unique pathophysiological mechanisms, comorbid diseases, and intervention. Even though the treatments for asthma have been highly developed, there are a high number of patients with asthma whose symptoms are not well controlled, particularly those with nocturnal asthma in which symptoms occur during the night and interfere with sleep. Moreover, nocturnal asthma also causes poor sleep quality, impairs quality of life, and deteriorates daytime cognitive performance. Overall, the prevalence of nocturnal asthma is estimated to be between 44-61% of patients with asthma. Pathophysiological mechanisms of nocturnal asthma included circadian rhythmicity and diurnal variation of inflammatory process, beta 2-adrenergic receptor polymorphism, and polluted environments. Furthermore, co-morbid conditions, such as obstructive sleep apnea and gastroesophageal reflux disease, may contribute to nocturnal asthma. In addition to optimal medical treatment, management of co-morbid conditions should be considered. Utilization of continuous positive airway pressure (CPAP) has been shown to significantly improve nocturnal symptoms in patients with co-existing obstructive sleep apnea as supported by numerous studies, but improvement of pulmonary function is still controversial. In addition, several studies also demonstrate that use of proton-pump inhibitors may assist those patients with gastroesophageal reflux disease resulting in an increase of peak expiration flow rate and/or FEV1.