是一种以嗜酸性粒细胞(eosinophile

1、bronchial asthmaEssentials of Diagnosis Episodic or chronic symptoms of airflow obstruction: breathlessness, cough, wheezing, and chest tightness. Symptoms frequently worse at night or in the early morning. Prolonged expiration and diffuse wheezes on physical examination. Limitation of airflow on pu

2、lmonary function testing or positive bronchial provocation challenge. Complete or partial reversibility of airflow obstruction, either spontaneously or following bronchodilator therapy. definition of bronchial asthma是一种以嗜酸性粒细胞(eosinophile granulocyte) 、肥大细胞(mast cell)为主，多种细胞参与的气道慢性炎症和气道高反应性为特征的疾病。表现

3、为不同程度的气道阻塞症状。临床上表现为反复发作性伴有哮鸣音的呼气性呼吸困难，胸闷或咳嗽，可自行或治疗后缓解。- 注：重点General Considerations Asthma is a common disease, affecting approximately 5% of the population. Men and women appear to be equally affected. Each year, approximately 470,000 hospital admissions and 5000 deaths in the USA are attributed to

4、asthma. Hospitalization rates have been highest among blacks and children, and death rates for asthma are consistently highest among blacks aged from 15 to 24 years. 支气管哮喘 一个全球性的严重健康问题 全球哮喘患病率差别很大： 新西兰:11% 欧洲 : 13.5% 太平洋岛屿：6.5% 中国:1%-4%普遍规律：城市高于农村儿童多于成人中国估计有哮喘患者约3,000万全球保守估计至少有哮喘患者1亿以上Mechanism of a

5、sthma（一）etiology 1. 遗传因素genetic factor; 2. 环境因素environmental agent 吸入性：尘螨、花粉、真菌等。 呼吸道感染： 药物：心得安、心得平、阿司匹林等 食入性：鱼、虾、蟹、蛋类、牛奶等。 气候变化： 运动、月经、精神等。 如： 豚草花粉 栎树花粉槭树花粉 杂草花粉 螨虫是室内的主要过敏原，大量存在于床上、沙发、地毯中，其活体、分泌物及死后虫体均有很强致敏性。Mechanism of asthma 1.气道炎症(inflammation) mast cell, eosinophile granulocyte, T cell 前列腺素PG

6、，白三烯LT，血小板活化因子PAF， 2.变态反应(allergies) 速发型哮喘反应（IAR） 迟发型哮喘反应（LAR） 双相型哮喘反应（OAR） 3.气道高反应性(airway hyperreactivity, AHR)气道对多种刺激因子出现过强或过早的收缩反应，是另一重要因素。4.神经机制 肾上腺素受体功能低下 迷走神经张力亢进 神经末梢裸露clinical manifestation Symptoms The frequency and severity of symptoms vary greatly from person to person and from time to t

7、ime in the same person. Some asthmatics have occasional episodes that are mild and brief. Others have mild coughing and wheezing much of the time, punctuated by severe exacerbations after exposure to known allergens, viral infections, exercise, or nonspecific irritants. Psychologic factors, particul

8、arly those associated with crying, screaming, or hard laughing, may precipitate symptoms. Usually, an attack begins acutely with paroxysms of wheezing, coughing, and shortness of breath or insidiously with slowly increasing manifestations of respiratory distress. Physical Examination During an acute

9、 attack, the patient shows varying degrees of respiratory distress, depending on the severity and duration of the episode. Tachypnea and tachycardia are present. The patient prefers to sit upright or even leans forward, uses accessory respiratory muscles, is anxious, and may appear to struggle for a

10、ir. Chest examination shows a prolonged expiratory phase with relatively high-pitched wheezes throughout inspiration and most of expiration. The chest may appear hyperinflated due to air trapping. Coarse rhonchi may accompany the wheezes, but fine crackles are not heard unless pneumonia, atelectasis

11、, or cardiac decompensation is also present. Laboratory Findings Static lung volumes and capacities Static lung volumes and capacities reveal various abnormalities, although these may not be detected when mild disease is in remission. Total lung capacity, functional residual capacity, and residual v

12、olume are usually increased. Vital capacity may be normal or decreased. Dynamic lung volumes and capacities Dynamic lung volumes and capacities are reduced but return toward normal after inhalation of an aerosolized bronchodilator. In patients with mild asymptomatic asthma, results may be normal. Be

13、cause expiratory flow is determined by the diameter of the airways and by the elastic recoil forces of the lung, Early in an acute attack, forced expiratory flow between 25 and 75% of the vital capacity (FEF25-75%) may decrease only modestly. As the attack progresses, the FVC and FEV1 progressively

14、decrease; blood routine test blood gas analysis Eosinophil Count Eosinophilia (> 250 to 400 cells/µL) is common regardless of whether allergic factors are shown to have an etiologic role. In many asthmatics, the degree of eosinophilia correlates with severity of asthma. Suppression of eosino

15、philia by systemic corticosteroids has been used as an index of the adequacy of the dosage. Sputum Examination In a patient with uncomplicated asthma, sputum is highly distinctive: tenacious, rubbery, and whitish. In the presence of infection, it may be yellowish, especially in adults. Many eosinoph

16、ils, often arranged in sheets, are seen microscopically, When bacterial respiratory infection is present-particularly when it has a bronchitic element-polymorphonuclear leukocytes and bacteria predominate. In uncomplicated asthma, sputum cultures rarely show pathogenic bacteria. Chest X-Ray Findings

17、 vary from normal to hyperinflation. Lung markings are commonly increased, particularly in chronic asthma. Atelectasis, most often affecting the right middle lobe, is common in children and may recur. Small areas of segmental atelectasis, often observed during exacerbations, may be misinterpreted as

18、 pneumonitis, but their rapid clearing suggests atelectasis. Allergen Identification Nonspecific irritants, particularly cigarette smoke, should be evaluated. Exacerbations related to environmental allergen exposures, a history of rhinitis, or a family history of atopic disorders suggests extrinsic

19、allergic factors. Allergens suggested by the history are best confirmed by an allergy evaluation that includes skin testing. A positive response indicates only potential allergic reactivity to the tested allergens. The clinical significance of results is determined by correlating them with the patte

20、rn of symptoms and with environmental exposures. Inhalational bronchial provocation testing can be used with allergens to establish the clinical significance of positive skin tests or with methacholine or histamine to assess the degree of airway hyperresponsiveness in known asthmatics. It also aids

21、in diagnosis when the symptoms are atypical.Diagnosis and Classification 病史 case history 临床表现 clinical situation 辅助检查 auxiliary examination· Asthma should be considered in anyone who wheezes; it is the likeliest diagnosis when typical paroxysmal wheezing starts in childhood or early adulthood a

22、nd is interspersed with asymptomatic intervals. A family history of allergy or asthma can be elicited from most asthmatics. Asthma may be classified into four categories according to severity. Because the course of asthma is variable, a patient may move from one category to another. Differential Dia

23、gnosis Chronic obstructive pulmonary disease and heart failure are the main considerations in the differential diagnosis of wheezing, although multiple small pulmonary emboli occasionally cause wheezing. Patients with hypersensitivity pneumonitis have a superficial clinical resemblance to asthmatics

24、 but generally have more constitutional symptoms after exposure to the offending substance and do not wheeze, except in allergic bronchopulmonary aspergillosis. Patients with bronchial obstructions secondary to malignancy, aortic aneurysm, endobronchial TB, or sarcoidosis occasionally present with w

25、heezing. Upper airway obstruction due to vocal cord dysfunction may be diagnosed using flexible bronchoscopy during an attack. （一 ）诊断标准 -重点1. 反复发作的喘息、呼吸困难、胸闷或咳嗽，多在接触变应原、冷空气、物理、化学性刺激、病毒性上呼吸道感染、运动等有关；2. 发作时在双肺可闻及散在弥漫性、以呼气相为主的哮鸣音，呼气相延长。3. 上述症状可经治疗或自行缓解。4. 症状不典型者至少有下列三项中的一项阳性：支气管激发试验或运动试验阳性；支气管舒张试验阳性（经吸

26、入2肾上腺素受体激动剂时，FEV1增加15以上，且FEV1增加绝对值200ml）；呼气流量峰值（PEF)日内变异率或昼夜波动率20。5.除外其他病所引起的喘息、胸闷和咳嗽哮喘诊断 肺功能的可逆性实验（三）支气管哮喘病情的评价哮喘病情的评价可分为以下两部分：1 . 非急性发作期病情的总评价：依据前一阶段哮喘症状出现的频度和程度、控制症状所需的药物及肺功能情况进行评估。2 . 急性发作期严重程度的评价：2. 哮喘急性发作期严重程度的评价哮喘急性发作是指气促、咳嗽、胸闷等症状突然发生，常有呼吸困难。以呼气流量降低为其特征。其程度轻重不一，病情加重可在数小时或数天内出现，偶尔可在数分钟内即危及生命，故应对其病情作出正确评估，以便给予及时有效的紧急治疗。九、哮喘的治疗-重点（一）脱离变应原（二）药物治疗：平喘药物§ 支气管舒张剂：§ 抗炎药：§ 其他药物：（三）缓解期的治疗或预防（二）药物治疗1. 支气管舒张剂： 2受体激动剂：兴奋腺苷环化酶，增加血中cAMP水平，使支气管平滑肌扩张。 短效吸入型2激动剂： 可持续46小时，每日需用34次。 药物：喘乐宁，喘康速，博利康尼 长效吸入型2激动剂：可12小时以上，每日可用药12次。 药物：沙美特罗，福莫特罗等。 口服短效及长效制剂茶碱类药物作用机理：