asthma asth·ma (āz'mə, ās'-)
|asthma (āz'mə) Pronunciation Key
A common inflammatory disease of the lungs characterized by episodic airway obstruction caused by extensive narrowing of the bronchi and bronchioles. The narrowing is caused by spasm of smooth muscle, edema of the mucosa, and the presence of mucus in the airway resulting from an immunologic reaction that can be induced by allergies, irritants, infection, stress, and other factors in a genetically predisposed individual. Common symptoms of asthma include wheezing, coughing, and shortness of breath.
A chronic disease of the respiratory system, characterized by sudden, recurring attacks of difficult breathing, wheezing, and coughing. During an attack, the bronchial tubes go into spasms, becoming narrower and less able to move air into the lungs. Various substances to which the sufferer has an allergy, such as animal hair, dust, pollen, or certain foods, can trigger an attack.