| Definition: |
A chronic asthma that is characterized by significant decline in pulmonary function and increase of airway inflammation at night. During sleep, recumbent posture causes a reduction in the lung volumes, respiratory muscle tone, and lung compliance. The overnight physiological abnormalities include: increased airway inflammation and decreased steroid responsiveness, increased pulmonary capillary blood volume, functional differences in blood/air volume ratios and mechanical coupling of the parenchyma to the airways. |