What Is Asthma? Symptoms, Causes, and Treatments

哮喘是一种慢性肺疾病，可能使呼吸困难。It features narrow, inflamed airways (bronchial tubes). "Asthma" is an ancient Greek word meaning "short breath," and as the name implies, it can leave you gasping for air. One of the telltale signs of an asthma attacks is wheezing with difficulty breathing. Other asthma symptoms include chest tightness, coughing, and shortness of breath.

当肺的呼吸管发炎时，它们可能会对吸入的环境过敏原和会引发哮喘的刺激性敏感。这些环境触发因素包括花粉，污染和烟草烟雾。运动也可能是某些人的哮喘触发因素。

谁哮喘？

美国约有2500万人患有哮喘；其中约有600万是孩子。这种情况平均影响男人和女人。

哮喘可能是致命的

哮喘导致超过1400万访问医生each year and nearly 2 million emergency room visits. And, tragically, asthma can kill. Most people who die from asthma are over age 50, but children sometimes die of the condition.

哮喘吸入剂和雾化器比口服药物和注射具有优势，因为它们直接将药物直接运送到您的气道。与其他形式的哮喘药物相比，它们的副作用也更少。

Asthma Inhalers

哮喘的最常见治疗方法涉及一种称为吸入器的装置。吸入器是一种将哮喘药物直接运送到气道的小型设备。吸入器有两种类型：

• 计量剂量吸入器（MDI）：MDI是最常见的吸入器。他们像气溶胶罐一样从吸入器上喷洒药物。
• Dry powder inhalers: Dry powder inhalers deliver a powdered medicine that does not spray from the inhaler. Instead, the user must inhale the medicine quickly and forcefully.

有时，MDI与称为垫片的设备一起使用。垫片有助于协调呼吸与哮喘药物的释放，并使用较小的药物，从而更容易呼吸。

Nebulizers

吸入器不能用于婴儿和非常小的孩子。对于他们来说，可以使用雾化器。雾化器由电力提供动力，以将哮喘药变成细雾。

呼吸是我们的身体吸入氧气和表达二氧化碳的过程。在哮喘发作中，这个过程变得更加困难。

When you inhale, air passes through your windpipe (trachea). Meanwhile your diaphragm contracts and moves downward creating air space in your chest cavity. The air enters your lungs, passing through the bronchial tubes and finally into tiny air sacs (alveoli).

Oxygen from the air passes from the alveoli and into the bloodstream through tiny blood vessels called capillaries. Capillaries deliver this oxygen-rich blood to pulmonary veins, which pass it to the left side of your heart. The heart then pumps the oxygen-rich blood to the rest of your body.

When you exhale, air that is rich in carbon dioxide (CO2) passes out of your lungs, through your windpipe, and out your body through your nose and/or mouth.

在哮喘发作期间，气道变得发炎和敏感。肿胀会使气道变窄，使呼吸困难，常常导致气喘吁吁。导致这种狭窄的三个因素：

• 炎
• 支气管痉挛
• Hyperreactivity (Asthma Triggers)

炎症是哮喘发作期间气道变窄的主要原因。It makes airways more swollen and sensitive. When airways are inflamed, air has a smaller passageway. In addition, the surrounding muscles of the airways may tighten during an asthma attack, further narrowing the opening for airflow.

When airways react to inflammation, they also produce more mucus. This thick, sticky liquid can clump together and also narrow air passages.

此外，某些过敏和炎症细胞（包括嗜酸性粒细胞在内的白细胞）积累在炎症部位，从而导致组织损害进一步缩小气道。该链反应导致与哮喘发作相关的呼吸困难。

The larger tubes that split off from your trachea and into your lungs are called your bronchial tubes. These tubes are surrounded by muscles. When the muscles of your bronchial tubes contract in asthma, they obstruct your airways, a process referred to as bronchospasm.

咳嗽and wheezing may be symptoms of bronchospasm, and bronchospasm can occur when the airways are irritated by cold air. Bronchospasm may come on suddenly. It can be treated by medicines called bronchodilators.

People with asthma may become overly sensitive (hyperreactive) to certain inhaled allergens or irritants. These are called triggers of asthma, and these triggers can cause inflammation and narrowing of your airways. This occurs because some people's bodies are immunologically inclined to overreact to certain substances. The precise substance that may cause such a reaction varies from person to person. In the next three slides, we'll review asthma triggers in more detail.

可以发起哮喘攻击的事情称为“触发器”。并非每个患有哮喘的人都有相同的触发因素。触发器可以是过敏原或刺激物。患有哮喘的人需要了解最佳管理和避免他们的触发因素。

识别和避免触发器可以帮助您防止进一步的哮喘发作。过敏者和免疫学家是专门帮助患者识别引起哮喘问题的刺激性和过敏症的医生。他们可以帮助制定一项计划，以避免哮喘触发因素以优化日常健康。

哮喘可以具有过敏性和非过敏性触发因素。过敏性哮喘触发因素包括许多过敏原。其中一些过敏原包括：

• 花粉
• 灰尘
• 模具
• Pets
• 一些食物，包括花生，鸡蛋，乳制品，大豆和鱼
• Sulfites
• 乳胶

Nonallergic asthma triggers include many irritants. Some of these come from environmental toxins, including tobacco smoke, smog, and various chemicals, dusts, and occupational gases. They can also come from medications, such as over-the-counter painkillers and beta-blockers. Sometimes respiratory infections can trigger asthma, and so can GERD. Exercise can also bring on asthma attacks.

哮喘在任何年龄都可以发展。但是，哮喘确实倾向于从2-6岁的儿童开始。在这个时代，哮喘通常是由尘螨，烟草烟雾和尘螨等过敏原触发的。在幼儿中，哮喘可能首先被诊断为反应性气道疾病（RAD）。

成年人也可以发展哮喘，只有大约30％的成人哮喘触发因素与过敏有关。成人哮喘的危险因素包括女性，肥胖，荷尔蒙波动，例如在怀孕或更年期后或更年期后经历的荷尔蒙波动以及病毒或其他感染。

过敏性（外部）哮喘是由过敏反应触发的类型。这是您的免疫系统响应刺激物的一个例子。过敏性哮喘是最常见的形式，影响了所有患者的一半以上。它通常可以用药物进行管理，并且往往比其他形式不那么严重。

Non-allergic (intrinsic) asthma is caused by factors other than allergies, such as exercise, stress, inhaling cold air, smoke, viral infections, and other irritants. This type of asthma is less common, develops more often in adults, and is more difficult to treat than allergic (extrinsic) asthma. In many cases this type seems to be more severe.

不同的人以不同的方式经历哮喘。当哮喘受到控制时，您的症状可能更少或没有症状。过敏性和非过敏性类型的哮喘症状都是相同的。他们包括

• 气促
• 喘息
• 咳嗽
• 胸部紧迫感
• 大量粘液产生

Not everyone with asthma will experience every symptom, and the severity of symptoms can vary depending on the individual—even in an individual symptoms may vary over time.

国家哮喘教育和预防计划根据患者的症状和肺功能测试将哮喘分类为这四个类别：

• Mild intermittent
• 轻度持久
• 中等持久
• 严重的持久

哮喘发作是哮喘症状的急性恶化。在急性哮喘发作中，有炎症，支气管痉挛和粘液过多。这些会导致症状，例如

• 呼吸困难
• 气促
• 喘息
• 咳嗽
• 干扰日常活动

通常，哮喘攻击可以用吸入器（吸入支气管扩张剂）来控制。当这种情况无效时，患者应致电911或立即带到急诊室。当哮喘没有对初始治疗做出反应时，可能会导致威胁生命的反应，称为状态哮喘。

有几种测试可以确定您是否患有哮喘和严重程度。Lung (pulmonary) function tests measure how functional your lungs are. These may include spirometry or peak flow meter tests.

支气管挑战测试有助于医生确定肺对环境触发的反应性。该测试包括甲氧胺挑战测试，组胺挑战测试和支气管前置测试。

血液测试测量在过敏反应期间释放的IgE抗体。其他测试可用于排除其他呼吸急促的原因，包括胃酸反流和睡眠呼吸暂停。有时会执行胸部X射线或心电图以检测肺部或其他状况的异物。

哮喘药物被归类为用于长期控制或快速缓解的药物。Most are inhaled rather than taken in tablet or liquid form, to act directly on the airways where the breathing problems start.

长期控制药物包括：

• Montelukast, oral medicine that helps prevent wheezing and shortness of breath
• 吸入皮质类固醇
• Cromolyn, taken using a nebulizer or inhaler
• Omalizumab (anti-IgE), given as an injection
• Long-acting beta2-agonists (bronchodilators)
• 白三烯修饰剂，用嘴吸收
• Theophylline, taken by mouth

快速浮力药物包括：

• Albuterol and other short-acting beta2-agonists (bronchodilators)

哮喘药物

吸入器和雾化器使用的常见药物包括以下三种类型：

• Inhaled Corticosteroids: Inhaled corticosteroids reduce airway inflammation. Sometimes these medicines are used even for people who don’t have any asthma symptoms, as they can help prevent future asthma attacks.
• Short-Acting Bronchodilators：支气管扩张剂没有类固醇。它们通过放松哮喘发作期间可以拧紧气道的微小肌肉来起作用。短作作用支气管扩张剂可以迅速缓解哮喘症状。
• Long-Acting Bronchodilators：每天服用长效支气管扩张剂，以帮助控制哮喘并防止未来的哮喘发作。长效支气管扩张剂的类型包括咸酚和甲诺醇。

• 哮喘是一种慢性肺疾病，可能使呼吸困难。It causes inflammation, swelling, and narrowing of the airways (bronchial tubes).
• 美国约有2500万人患有哮喘；其中600万是孩子。
• 根据身体检查和患者病史诊断哮喘。通过呼吸测试证实了这一点。
• Asthma is caused by three major factors: inflammation, bronchospasm, and hyperreactivity.
• 过敏在某些但并非所有哮喘病例中都起作用。
• Allergens and irritants can cause asthma attacks. When they do, they are called "triggers."
• 管理哮喘的最佳方法是尝试避免触发因素，这对哮喘的每个人来说都是不同的。
• 药物可以逆转或预防支气管痉挛。