- asthma
- An inflammatory disease of the lungs characterized by reversible (in most cases) airway obstruction. Originally, a term used to mean “difficult breathing”; now used to denote bronchial a.. SYN: reactive airway disease. [G.]- bronchial a. an acute or chronic disorder characterized by widespread and largely reversible reduction in the caliber of bronchi and bronchioles, due in varying degrees to smooth muscle spasm, mucosal edema, and excessive mucus in the lumens of airways; cardinal symptoms are dyspnea, wheezing, and cough; attacks or exacerbations may be induced by airborne allergens ( e.g., molds, pollens, animal dander, dust mite and cockroach antigens), inhaled irritants ( e.g., cold air, cigarette smoke, ozone), physical exercise, respiratory infection, psychological stress, or other factors; the signs and symptoms of bronchial a. are caused by the local release of spasmogens and inflammatory mediators (histamines, leukotrienes, prostaglandins) and other substances from mast cells, eosinophils, lymphocytes, neutrophils, and epithelial cells; airway caliber may be abruptly and drastically reduced during a paroxysm or after diagnostic challenge with methacholine or histamine, and may quickly return to normal after administration of a bronchodilator (inhaled β-adrenergic agonist or subcutaneous epinephrine).A. is a common disease, with an incidence of about 5% in the U.S., and a leading cause of disease and disability in persons between 2 and 17 years of age. It is responsible for 14.5 million outpatient visits and 5000 deaths yearly in this country. From 1980 to 1994 the prevalence of a. increased 75%; the greatest increase (160%) occurred in children under age 5. A. first occurring in childhood is more likely to be allergic in origin and to show seasonal variation. Chronic sinusitis and gastroesophageal reflux disease are statistically correlated with a.. A subset of people with allergic a. also have nasal polyps and sensitivity to aspirin and most other nonsteroidal antiinflammatory drugs. Occupational exposure to airborne irritants or allergens is increasingly recognized as a cause of chronic a. in adults. Current views of the pathophysiology of a. emphasize its inflammatory component and the risk of gradual, irreversible airway remodeling due to subepithelial fibrosis in poorly controlled a.. Current recommendations for treatment of chronic or severe a. call for use of antiinflammatory drugs (particularly inhaled corticosteroids). Other treatments include β2-adrenergic bronchodilators (albuterol, terbutaline, salmeterol), xanthines (theophylline, oxtriphylline, dyphylline), mast cell stabilizers (cromolyn, nedocromil), and antileukotrienes (montelukast, zafirlukast, zileuton). Self-monitoring of peak respiratory flow rate with a simple portable device helps patients adjust drug doses for optimum effect. Avoidance of allergens, irritants, and other known triggers is essential to good control.- cardiac a. an asthmatic attack, the bronchoconstriction being secondary to the pulmonary congestion and edema of left ventricular failure.- catarrhal a. SYN: bronchitic a..- cotton-dust a. SYN: byssinosis.- dust a. a. aggravated by inhalation of dust, especially seen as occupational disease resulting from cotton dust.- extrinsic a. bronchial a. resulting from an allergic reaction to foreign substances, such as inhaled particles, vapors, or gases, or ingested foods, beverages, or drugs.- intrinsic a. bronchial a. in which no extrinsic causes can be identified, and which is assumed to be due to an endogenous process, possibly allergic.- miller a. a. caused by flour or grain allergens.- miner's a. the dyspnea of anthracosis or other pneumoconioses in miners.- steam-fitter's a. a. associated with asbestosis acquired by exposure to asbestos-insulated heating and plumbing components.- stripper's a. a. associated with byssinosis.
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asth·ma 'az-mə n a chronic lung disorder that is marked by recurring episodes of airway obstruction (as from bronchospasm) manifested by labored breathing accompanied esp. by wheezing and coughing and by a sense of constriction in the chest, and that is triggered by hyperreactivity to various stimuli (as allergens or rapid change in air temperature)* * *
n.the condition of subjects with widespread narrowing of the bronchial airways, which changes in severity over short periods of time (either spontaneously or under treatment) and leads to cough, wheezing, and difficulty in breathing. Bronchial asthma may be precipitated by exposure to one or more of a wide range of stimuli, including allergen, drugs (such as aspirin and other NSAIDs and beta blockers), exertion, emotion, infections, and air pollution. The onset of asthma is usually early in life and in atopic subjects (see atopy) may be accompanied by other manifestations of hypersensitivity, such as hay fever and dermatitis; however, the onset may be delayed into adulthood or even middle or old age. Treatment is with bronchodilator, with or without corticosteroids, usually administered via aerosol or dry-powder inhalers, or - if the condition is more severe - via a nebulizer. Oral corticosteroids are reserved for those patients who fail to respond adequately to these measures. Severe asthmatic attacks may need large doses of oral corticosteroids (see status asthmaticus). Selection of treatment for individual cases is made using stepped guidelines issued by respiratory organizations, e.g. the British and American Thoracic Societies and the European Respiratory Society. Avoidance of known allergens, especially the house dust mite, allergens arising from domestic pets, and food additives, will help to reduce the frequency of attacks, as will the discouragement of smoking.Cardiac asthma occurs in left ventricular heart failure and must be distinguished from bronchial asthma, as the treatment is quite different.• asthmatic adj.* * *
as·thma (azґmə) [Gr. asthma panting] recurrent attacks of paroxysmal dyspnea, with airway inflammation and wheezing due to spasmodic contraction of the bronchi. Some cases are allergic manifestations in sensitized persons (allergic a.); others are provoked by factors such as vigorous exercise, irritant particles, psychologic stresses, and others. Called also bronchial a. and spasmodic a. asthmatic adj
Medical dictionary. 2011.
