KPDS ÜDS OKUMA PARÇASI - 16

Asthma may be defined as a malady characterized by attacks of breathlessness due to paroxysmal narrowing of the smaller bronchi and bronchioles. Asthma may start at any age, but most commonly in childhood. The typical attack starts suddenly with breathlessness and wheezing, the difficulty being mainly in expiration. A small amount of viscid mucus is usually expectorated towards the end of the attack. Attacks may occur at any time, but especially during the night or in the early morning. Their duration is variable, some ending in an hour or so, others, especially if complicated by bronchitis, continuing for days. The frequency of attacks varies from one or two a year to several daily. During attacks the lungs become over-distended with air, since the obstruction to respiration is greater in expiration than in inspiration and the muscles of forced inspiration which are brought into action are stronger than the expiratory muscles.