Λεξικό .. Bronchospasm

Bronchospasm

The excessive and prolonged contraction of the smooth muscle of the in the walls bronchi and bronchioles, causing an acute narrowing and obstruction of the lumen of the lower respiratory airways. Bronchospasm is the most likely cause of acute and rapidly reversible attacks of asthma. Exercise induced asthma is the conventional term for transient airway narrowing in a known asthma in association with strenuous exercise usually lasting 5-10 minutes with a decline in pulmonary function by at least 10%. Exercise induced asthma will be referred to as exercise induced bronchospasm in an asthmatic. Exercise-induced bronchospasm (EIB ) is the same phenomenon in an individual without known asthma. EIB can be seen in healthy individuals including children as well as defense recruits and competitive or elite athletes. The diagnosis with objective exercise challenge methods in conjunction with history is delineated. Management is characterized with pharmacotherapy and non pharmacotherapeutic measures for underlying asthma as well as exercise induced bronchospasm and inhalant allergy. Children can successfully participate in all sports if asthma is properly managed[1].

Airways hyperresponsiveness is a cardinal feature of asthma but remains unexplained. In asthma, the airway smooth muscle cell is the key end-effector of bronchospasm and acute airway narrowing, but in just the past five years our understanding of the relationship of responsiveness to muscle biophysics has dramatically changed. It has become well established, for example, that muscle length is equilibrated dynamically rather than statically, and that non-classical features of muscle biophysics come to the forefront, including unanticipated interactions between the muscle and its time-varying load, as well as the ability of the muscle cell to adapt rapidly to changes in its dynamic microenvironment. These newly discovered phenomena have been described empirically, but a mechanistic basis to explain them is only beginning to emerge[2].

References

1. Randolph C. Exercise-induced bronchospasm in children. Clin Rev Allergy Immunol. 2008 Apr;34(2):205-16

2. Fredberg JJ. Bronchospasm and its biophysical basis in airway smooth muscle. Respir Res. 2004 Feb 26;5:2.