![]() Melatonin, a sleep inducing hormone, has a proinflammatory effect in subjects with nocturnal asthma. These findings suggest a blunted adrenal response to corticotropin in nocturnal asthma, which may play a permissive role in the nocturnal worsening of asthma. Corticotropin peak levels and the area under the 24-hour curve were significantly higher in nocturnal asthmatics, but these elevations were not accompanied by a commensurate increase in cortisol levels, which were the same in nocturnal asthmatics as in non-nocturnal asthmatics and healthy controls. One study evaluated the effects of hypothalamic and pituitary control of the cortisol response in nocturnal asthma by measuring corticotropin-releasing hormone, corticotropin, and cortisol levels every two hours. With cortisol, for example, peak levels occur upon awakening while trough levels are noted around midnight. ![]() Several hormones are secreted in a circadian pattern that can contribute to nocturnal airway inflammation and asthma in predisposed individuals. ![]() Circadian changes in lung volume, distal airway inflammation, glucocorticoid receptor affinity, pulmonary capillary blood volume, and beta-2 adrenergic receptor function may also contribute. Thus, nocturnal asthma appears to reflect an exaggeration of the effects of normal changes in neurohormonal activation that have time-related rhythms (chronobiology). The normal population also experiences a circadian change in lung function, but the peak-to-trough swings in peak expiratory flow rate are only 5 to 8 percent compared to a variation of 15 to 50 percent or more in asthmatics. PathophysiologyĪsthma is associated with a circadian pattern in lung function, with the best function typically occurring at approximately 4 PM, and the worst at around 4 AM. Thus, nocturnal asthma symptoms suggested a deterioration in asthma control that had been present over several days. In addition, 79 percent of these patients had premortem complaints of asthma affecting their sleep and occurring every night in 42 percent. As an example, over a one-year period, 53 percent of asthma deaths in one report occurred at night. The occurrence of nocturnal asthma symptoms is also reflected in mortality statistics. Nocturnal asthma is common and approximately 30 to 70 percent of patients with asthma report nocturnal asthma symptoms at least once a month. In particular, nocturnal asthma symptoms are felt to be a characteristic feature of asthma that is not well-controlled. Mayo Clinic.Nocturnal asthma is defined by a drop in forced expiratory volume in 1 second (FEV1) of at least 15% between bedtime and awakening in patients with clinical and physiologic evidence of asthma. As many as 75% of asthmatic subjects are awakened by asthma symptoms at least once per week, with approximately 40% experiencing nocturnal symptoms on a nightly basis. An extensive body of research has demonstrated that nocturnal symptoms of cough and dyspnea are accompanied by circadian variations in airway inflammation and physiologic variables, including airflow limitation and airways hyper responsiveness. Nocturnal worsening of asthma is a well-described and important problem that must be considered in the management of patients with asthma. ![]() Peroral endoscopic myotomy (POEM) for achalasia. 2019 Seoul consensus on esophageal achalasia guidelines. Achalasia: Treatment, current status and future advances. National Organization for Rare Disorders. ![]()
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