Airway structure and function in asthma

As asthma is a disease characterized by muscle spasm, airways inflammation and mucus plugging of the airways, one can only generalize about their relative importance. For example, when an asthmatic attack is easily and completely reversible by drugs that relax smooth muscle, it is likely that smooth muscle spasm is the major cause of the airways obstruction. It also seems probable that when patients have airways reactivity that waxes and wanes in severity with intermittent severe attacks of asthma, the airways may be thickened by inflammation and the smooth muscle may be unloaded by softening of the cartilage. Finally, when patients die of asthma and their airways are solidly plugged, it seems reasonable to conclude that the plugs are the cause of death. The common pathway in these widely different situations may be the inflammatory reaction. Indeed, it seems likely that understanding the basic nature of the inflammatory response in airways tissue and its effects on wall thickness and the mucus secreting apparatus will provide clear insights into how to reverse the asthmatic state.