Nocturnal asthma

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

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.^[1] The pathophysiology of nocturnal asthma is closely associated with the chronobiology and the science of biologic processes that have time-related rhythms. Hence, understanding the circadian rhythm is important to interpret the changes in pulmonary function that occurs in sleeping asthmatics. A large population based study reported dyspneic episodes without therapy in asthmatics occurred between 10 P.M. and 7 A.M.^[2] Another population based survey that assessed 7729 patients, reported approximate 74% patients woke-up at least once a week with symptoms, 64% woke-up three times per week, and 39% patients woke-up every night with symptoms.^[3]

Nocturnal worsening of asthma is very common clinical finding in asthmatics affecting approximately 75% of asthmatics who awaken at least once per week because of symptoms, and approximately 40% experience nocturnal symptoms on a nightly basis.^[1][4]

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

The pathophysiology of nocturnal asthma is closely associated with the chronobiology and the science of biologic processes that have time-related rhythms.

• Alterations in beta2-adrenergic^[1][2] and glucocorticoid receptors^[3] and hypothalamic-pituitary-adrenal axis function have shown to play a role in modulating the nocturnal asthma phenotype, and recent studies have suggested elevation and phase delay of peak serum melatonin,^[4] a neurohormonal controller of circadian rhythms, to play an important role in the pathogenesis of nocturnal asthma.^[5][6]
• The increase of CD51 at night, in patients with nocturnal asthma, may be related to increased airway inflammation and repair processes in response to injury.^[7]
• Research has demonstrated that the greatest inflammation in nocturnal asthmatics occurs in the proximal alveolar tissue at 4 AM. Inflammatory mediators such as eosinophils, macrophages and CD4+ lymphocytic infiltration, were shown to accumulate in the proximal alveolar tissue and contribute to the variation in lung function.^[8][9]
• The development of nocturnal airway obstruction in asthma has been associated with the enhanced production of oxygen radicals by air-space cells. Because oxygen radicals can cause airway injury and thus enhance bronchial obstruction, it has been postulated that the release of these reactive compounds is causally associated with nocturnal asthma.^[10][11][12]
• Worsening of nocturnal asthma has been associated to the secondary increase in the levels of inflammatory mediators such as leukotrienes, interleukins, and histamine.^{[10][13][14][15][16][17]}
• Enhanced parasympathetic activity is associated with bronchial hyper-reactivity, which is characteristic of asthma. It is believed this increased cholinergic tone may be related to the pathogenesis of bronchial asthma.^[18][19]

Template:WH Template:WS

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Template:WH Template:WS

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Template:WH Template:WS

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Vishnu Vardhan Serla M.B.B.S. [2]

Nocturnal worsening of asthma is very common clinical finding in asthmatics affecting approximately 75% of asthmatics who awaken at least once per week because of symptoms, and approximately 40% experience nocturnal symptoms on a nightly basis.^[1][2]

Template:WH Template:WS

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Template:WH Template:WS

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Vishnu Vardhan Serla M.B.B.S. [2]

• It is recognized with increasing frequency, that patients who have both obstructive sleep apnea and bronchial asthma, often improve tremendously when the sleep apnea is diagnosed and treated.^[1][2]
• However, CPAP has not shown to be effective in patients with nocturnal asthma alone.^[3]

Template:WH Template:WS