bronchial asthma
bronchial asthma
Introduction Bronchial asthma is a chronic inflammatory condition involving a variety of cells including eosinophils, mast cells, T lymphocytes, neutrophils, and epithelial cells of the airway, as well as cellular elements, which gives rise to the increase of airway hyper-reactivity. Extensive changeable and reversible ventilation restriction is common and can cause recurrent tachypnea, feeling of out of breath, and coughing. The symptoms are more usually present and aggravated at night or early in the morning. Remission might be achieved spontaneously or following treatment
Introduction Bronchial asthma is a chronic inflammatory condition involving a variety of cells including eosinophils, mast cells, T lymphocytes, neutrophils, and epithelial cells of the airway, as well as cellular elements， which gives rise to the increase of airway hyper-reactivity. Extensive changeable and reversible ventilation restriction is common and can cause recurrent tachypnea, feeling of out of breath, and coughing. The symptoms are more usually present and aggravated at night or early in the morning. Remission might be achieved spontaneously or following treatment
etiology The pathogenesis of asthma is complicated and is affected by genetics and the environment. It is a multigene disoder and closely related to atopy. Most patients have prior history of eczema, allergic rhinitis, food or drug allergy, and quite a few patients have family history. The formation and attack of asthma is also a consequence of the function of multiple environmental factors such as inhalation of allergens respiratory tract infection and coldness
etiology The pathogenesis of asthma is complicated and is affected by genetics and the environment. It is a multigene disoder and closely related to atopy. Most patients have prior history of eczema, allergic rhinitis, food or drug allergy, and quite a few patients have family history. The formation and attack of asthma is also a consequence of the function of multiple environmental factors such as inhalation of allergens, respiratory tract infection, and coldness
epidemiology 160 million patients in the word prevalence: 1%0--5%, 1% in china Prevalence in male is similar to that in female The onset is before 12 years of age in the majority Family history could be found in 20% patients Related to allergic rhinitis, eczema and nasal polyp
epidemiology • 160 million patients in the word • prevalence：1%--5%，1% in china • Prevalence in male is similar to that in female • The onset is before 12 years of age in the majority • Family history could be found in 20% patients • Related to allergic rhinitis, eczema and nasal polyp
etiology 1. Genetic factors: multigene inheritance heritability 70-80% 2. Predisposing factors: air pollution inhalants: dust mites, pollen ) infections 3) food 4) change of weather 5)mental factors 6) exercise运动 7)drugs 8)menstruation, pregnacy
etiology • １．Genetic factors: multigene inheritance heritability 70-80% • ２．Predisposing factors: air pollution 1） inhalants：dust mites、pollen 2） infections 3） food 4） change of weather 5） mental factors 6） exercise运动 7） drugs 8） menstruation, pregnacy
Pathogenic mechanism Asthma is Characteristic of hyper- reactivity of the airway Chronic (allergic) inflammation is the basic lesion of asthma
Pathogenic mechanism • Asthma is Characteristic of hyperreactivity of the airway • Chronic （allergic） inflammation is the basic lesion of asthma
Allergic inflammation Is divided into 3 subtypes according to the different cytokines secreted by cd4 Th cell Tho, ThI and Th2o Investigations have shown that allergic reactions like asthma are mediated by Th2 cells There is an increase or predominance of Th2 or its cytokines. The resulting airway inflammation could be classified into the following two types 1. IgE mediated and T lymphocyte dependent pthway 2. Nonlge mediated and t lymphocyte dependent pathway
Allergic inflammation Is divided into 3 subtypes according to the different cytokines secreted by CD4 Th cell: Th0、Th1 and Th2。Investigations have shown that allergic reactions like asthma are mediated by Th2 cells. There is an increase or predominance of Th2 or its cytokines. The resulting airway inflammation could be classified into the following two types: 1. IgE mediated and T lymphocyte dependent pthway 2.NonIgE mediated and T lymphocyte dependent pathway
Immunologic factors the role of ige mediation The combination of allergen with specific IgE triggers the degranulation of the mast cells and eosinophils, resulting in release of mediators including leukotrienes C, D, E, and the subsequent smooth muscle contraction edema of the mucosa increase of secretion and finally stenosis of the bronchioles which all contribute to asthma Total serum Ige or specific serum Ige titer increase is seen in patients with asthma, indicating type I allergic reactions might be present
Immunologic factors the role of IgE mediation • The combination of allergen with specific IgE triggers the degranulation of the mast cells and eosinophils, resulting in release of mediators including leukotrienes C,D,E, and the subsequent smooth muscle contraction, edema of the mucosa, increase of secretion, and finally stenosis of the bronchioles ,which all contribute to asthma. Total serum IgE or specific serum IgE titer increase is seen in patients with asthma , indicating type I allergic reactions might be present
nonagE mediated, T lymphocyte dependent pathway In delayed type allergic reaction, Th2 cell directly initiates imflammatory response by activation and agglutination of various inflammatory cells via the release of multiple cytokines(IL-4、I-13、I-3 IL-5)
nonIgE mediated, T lymphocyte dependent pathway • In delayed type allergic reaction, Th2 cell directly initiates imflammatory response by activation and agglutination of various inflammatory cells via the release of multiple cytokines(IL-4、IL-13、IL-3、 IL-5）
Neuromental factors The complicated autonomic innervation of the bronchopulmonary sysytem includes cholinergic, adrenergic nonadrenergIc and noncholinergic nerves. B-adrenergic receptor malfunction and the increased tone of the vagus, or with simultaneous increase of a adrenergic reactivity, would promote contraction of the smooth muscle and secretion of the glands, resulting in attack of asthma
Neuromental factors The complicated autonomic innervation of the bronchiopulmonary sysytem includes cholinergic, adrenergic ,nonadrenergic and noncholinergic nerves. -adrenergic receptor malfunction and the increased tone of the vagus, or with simultaneous increase of - adrenergic reactivity,would promote contraction of the smooth muscle and secretion of the glands, resulting in attack of asthma