Asthma is a chronic disease of the airways that makes breathing difficult. With asthma, there is inflammation of the air passages that results in a temporary narrowing of the airways that carry oxygen to the lungs. This results in asthma symptoms, including coughing, wheezing, shortness of breath, and chest tightness. Some people refer to asthma as “bronchial asthma.”

Even though there are seemingly miraculous treatments for asthma symptoms, asthma is still a serious — even dangerous — disease that affects more than 25 million Americans and causes nearly 2 million emergency room visits ever year.

In each of the following sections, there are in-depth articles that link to the topics. Be sure to read each health topic so you have a greater understanding of asthma and how it is diagnosed and treated.

●Airway obstruction. During normal breathing, the bands of muscle that surround the airways are relaxed, and air moves freely. But in people with asthma, allergy-causing substances and environmental triggers make the bands of muscle surrounding the airways tighten, and air cannot move freely. Less air causes a person to feel short of breath, and the air moving through the tightened airways causes a whistling sound known as wheezing.

●Inflammation. People with asthma have red and swollen bronchial tubes. This inflammation is thought to contribute greatly to the long-term damage that asthma can cause to the lungs. And, therefore, treating this inflammation is key to managing asthma in the long run.

●Airway irritability. The airways of people with asthma are extremely sensitive. The airways tend to overreact and narrow due to even the slightest triggers such as pollen, animal dander, dust, or fumes.

Asthma may occur at any age, although it's more common in younger individuals (under age 40).

People who have a family history of asthma have an increased risk of developing the disease. Allergies and asthma often occur together. Smoking with asthma, a dangerous combination, is still seen commonly.

However, anyone can develop asthma at any time, and adult-onset asthma happens frequently. If you have adult-onset asthma, your doctor will instruct you in using the asthma inhalers and other asthma medications to prevent further breathing problems.

Asthma is characterized by inflammation of the bronchial tubes with increased production of sticky secretions inside the tubes. People with asthma experience symptoms when the airways tighten, inflame, or fill with mucus. Common asthma symptoms include:

●Coughing, especially at night

●Wheezing

●Shortness of breath

●Chest tightness, pain, or pressure

Still, not every person with asthma has the same symptoms in the same way. You may not have all of these symptoms, or you may have different symptoms at different times. Your asthma symptoms may also vary from one asthma attack to the next, being mild during one and severe during another.

Some people with asthma may go for extended periods without having any symptoms, interrupted by periodic worsening of their symptoms called asthma attacks. Others might have asthma symptoms every day. In addition, some people may only have asthma during exercise or asthma with viral infections like colds.

Mild asthma attacks are generally more common. Usually, the airways open up within a few minutes to a few hours. Severe attacks are less common but last longer and require immediate medical help. It is important to recognize and treat even mild asthma symptoms to help you prevent severe episodes and keep asthma under better control.

Early warning signs are changes that happen just before or at the very beginning of an asthma attack. These signs may start before the well-known symptoms of asthma and are the earliest signs that your asthma is worsening.

In general, these signs are not severe enough to stop you from going about your daily activities. But by recognizing these signs, you can stop an asthma attack or prevent one from getting worse. Early warning signs of asthma include:

●Frequent cough, especially at night

●Losing your breath easily or shortness of breath

●Feeling very tired or weak when exercising

●Wheezing or coughing after exercise

●Feeling tired, easily upset, grouchy, or moody

●Decreases or changes in lung function as measured on a peak flow meter

●Signs of a cold or allergies (sneezing, runny nose, cough, nasal congestion, sore throat, and headache)

●Trouble sleeping

If you have early warning signs or symptoms of asthma, you should take more asthma medication as described in your asthma action plan.

An asthma attack is the episode in which bands of muscle surrounding the airways are triggered to tighten. This tightening is called bronchospasm. During the attack, the lining of the airways becomes swollen or inflamed and the cells lining the airways produce more and thicker mucus than normal.

All of these factors — bronchospasm, inflammation, and mucus production —cause symptoms such as difficulty breathing, wheezing, coughing, shortness of breath, and difficulty performing normal daily activities. Other symptoms of an asthma attack include:

●Severe wheezing when breathing both in and out

●Coughing that won't stop

●Very rapid breathing

●Chest pain or pressure

●Tightened neck and chest muscles, called retractions

●Difficulty talking

●Feelings of anxiety or panic

●Pale, sweaty face

●Blue lips or fingernails

The severity of an asthma attack can escalate rapidly, so it's important to treat these asthma symptoms immediately once you recognize them.

Without immediate treatment, such as with your asthma inhaler or bronchodilator, your breathing will become more labored. If you use a peak flow meter at this time, the reading will probably be less than 50%.

As your lungs continue to tighten, you will be unable to use the peak flow meter at all. Gradually, your lungs will tighten so there is not enough air movement to produce wheezing. This is sometimes called the “silent chest,” and it is an ominous sign. You need to be transported to a hospital immediately. Unfortunately, some people interpret the disappearance of wheezing as a sign of improvement and fail to get prompt emergency care.

If you do not receive adequate asthma treatment, you will eventually be unable to speak and will develop a bluish coloring around your lips. This color change, known as cyanosis, means you have less and less oxygen in your blood. Without aggressive treatment for this asthma emergency, you will lose consciousness and eventually die.

If you are experiencing an asthma attack, follow the “Red Zone” or emergency instructions in your asthma action plan immediately. These symptoms occur in lifethreatening asthma attacks. You need medical attention right away.

Asthma affects as many as 10% to 12% of children in the United States and is the leading cause of chronic illness in children. For unknown reasons, the incidence of asthma in children is steadily increasing. While asthma symptoms can begin at any age, most children have their first asthma symptoms by age 5.

Not all children with asthma wheeze. Chronic coughing with asthma may be the only obvious sign, and a child's asthma may go unrecognized if the cough is attributed to recurrent bronchitis.

Not everyone with asthma has the usual symptoms of cough, wheezing, and shortness of breath. Sometimes individuals have unusual asthma symptoms that may not appear to be related to asthma. Some “unusual” asthma symptoms may include the following:

●rapid breathing

●sighing

●fatigue

●inability to exercise properly (called exercise-induced asthma)

●difficulty sleeping or nighttime asthma

●anxiety

●difficulty concentrating

●chronic cough without wheezing

Also, asthma symptoms can be mimicked by other conditions such as bronchitis, vocal cord dysfunction, and even heart failure.

It's important to understand your body. Talk with your asthma doctor and others with asthma. Be aware that asthma may not always have the same symptoms in every person.

Sometimes a virus or bacterial infection is an asthma trigger. For instance, you might have a cold virus that triggers your asthma symptoms. Or your asthma can be triggered by a bacterial sinus infection. Sinusitis with asthma is common.

It's important to know the signs and symptoms of respiratory tract infections and to call your health care provider immediately for diagnosis and treatment. For instance, you might have symptoms of increased shortness of breath, difficulty breathing, or wheezing with a bronchial infection. In people who don't have asthma, the bronchial infection may not trigger the same debilitating symptoms. Know your body and understand warning signs that an infection might be starting. Then take the proper medications as prescribed to rid the infection and regain control of your asthma and health.

Your doctor or asthma specialist plays the first and most significant role in helping you get control of your asthma. Not only does your doctor serve as the one who can accurately diagnose and prescribe treatment for your asthma, your doctor may become a close, dependable friend who can give you support when your concerns turn into ongoing worries and anxieties.

At the initial exam, your doctor will obtain a detailed medical history, including any information on asthma symptoms, how you feel, known asthma and allergy triggers, your activity level and diet, your home and work environment, and family history. During this evaluation, it is important that you talk openly with your doctor about your asthma symptoms and triggers. Some questions you might consider beforehand include:

●Shortness of breath

●Wheezing, possibly triggered by allergies, a cold, sinus infection, or bronchitis

●Frequent cough or just coughing at night

●Severe wheezing when breathing both in and out

●Rapid breathing

●Chest pain or pressure

●Difficulty talking

●Feelings of anxiety or panic

●Pale, sweaty face

●Blue lips or fingernails

After talking with you about your asthma symptoms and possible asthma triggers, your doctor will do a physical exam, laboratory testing, and other possible asthma tests. This will allow you to have a firm understanding of your breathing problems and will be the basis for the suggested plan of asthma treatment.

Your doctor may use one or more of the following asthma tests in diagnosing asthma. These tests are used to assess your breathing and to monitor the effectiveness of asthma treatment.

Spirometry a lung (or pulmonary) function test that measures how much air you can exhale. This asthma test confirms the presence of airway obstruction that improves with treatment, which is very characteristic of asthma, and can accurately measure the degree of lung function impairment. This test can also monitor your response to asthma medications and is recommended for adults and children over age 5.

Peak Flow Testing a self-assessment you can do at home to evaluate lung function. The peak expiratory flow rate (PEFR) provides a reliable objective measure of airway function. Your doctor will go over how to use a peak flow meter, which involves taking a deep breath and blowing out as hard as you can. Peak flow is the highest airflow velocity that you can achieve. When done accurately, a drop in the peak flow measurement reflects an obstruction in your airways. While peak flow is less accurate than office spirometry for monitoring of lung function, peak flow monitoring at home can help you manage your symptoms at home and help indicate when an asthma attack may be approaching.

Chest X-Ray while not routinely required, if there are symptoms that may be caused by another condition such as pneumonia, your doctor may want to do a chest X-ray. Or, if your asthma treatment is not working as well as it should, a chest X-ray may help to clarify the problem.

If you or a loved one has asthma, you should know about the most effective asthma treatments for short-term relief and long-term control. Understanding asthma treatments will enable you to work with your asthma doctor to confidently manage your asthma symptoms daily. When you do have an asthma attack or asthma symptoms, it's important to know when to call your doctor or asthma specialist to prevent an asthma emergency. Be sure to read all the in-depth articles that link to topics within each of the following sections. By doing so, you will gain new insight into asthma and how it's treated.

Asthma medications can save your life — and let you live an active life in spite of your asthma. There are two basic types of drugs used in asthma treatment.

Anti-inflammatory drugs, particularly inhaled steroids, are the most important treatment for most people with asthma. These lifesaving medications prevent asthma attacks and work by reducing swelling and mucus production in the airways. As a result, the airways are less sensitive and less likely to react to asthma triggers and cause asthma symptoms.

Bronchodilators relieve the symptoms of asthma by relaxing the muscles that can tighten around the airways. This helps to open up the airways.

Short-acting bronchodilator inhalers are often referred to as rescue inhalers and are used to quickly relieve the cough, wheeze, chest tightness, and shortness of breath caused by asthma. They may also be used prior to exercise for people with exerciseinduced asthma. These should not be used daily in the routine treatment of asthma. If you need to use a short-acting bronchodilator as a rescue inhaler more than twice a week, then your asthma is not optimally controlled. Ask your doctor about improving your asthma controller medication.

Long-acting bronchodilators are used in combination with inhaled steroids for control of asthma symptoms or when someone has ongoing asthma symptoms despite treatment with a daily inhaled steroid. Long-acting bronchodilators are never used alone as long-term therapy for asthma.

Asthma inhalers are the most common and effective way to deliver asthma drugs to the lungs. They are available in different types that require different techniques for use. Some inhalers deliver one medication and others contain two different medications.

If you're having difficulty using small inhalers, your doctor may prescribe an asthma nebulizer, also known as a breathing machine. The asthma nebulizer uses a mouthpiece or mask and is typically used for infants, small children, older adults, or anyone who has difficulty using inhalers with spacers. The nebulizer changes asthma medications from a liquid to a mist, so that they can be more easily inhaled into the lungs. This takes a few more minutes than using inhalers.

If you have a serious asthma attack (exacerbation), your doctor may prescribe a short course of oral corticosteroids. When used orally for less than two weeks, the side effects of corticosteroids are only temporary, but when used for many months, these side effects can be serious and permanent. After the severe symptoms of your asthma attack have been successfully treated and controlled, your doctor will work with you to minimize your need for prednisone in the future. Faithfully taking an inhaled corticosteroid every day is the most commonly successful method to do this.

allergy ['ælɚdʒi] n.过敏症

asthma ['æzmə] n.哮喘

bronchospasm ['brɔŋkəspæzəm] n.支气管痉挛

cyanosis [,saiə'nosis] n.发绀

debilitate [di'biliteit] vt.使衰弱,使虚弱

escalate ['eskəleit] vi/vt.逐步增强

exacerbation [ek,sæsə'beiʃən] n.恶化

exhale [ɛks'hel] vi.呼气,呼出

fume [fjum] n/vi.熏，烟气

grouchy ['graʊtʃi] adj.不高兴，不满的

incidence ['insidəns] n.发病率

inhale [in'hel] vi.吸入，吸气

irritability [,irətə'biləti] n.过敏性,兴奋性

mimicked [mimikt] v.模仿

miraculous [mi'rækjələs] adj.不可思议的

mist [mist] n.薄雾

moody ['mudi] adj.郁郁寡欢的

nebulizer ['nɛbjə,laizɚ] n.喷雾剂，喷雾器

ominous ['ɑminəs] adj.预兆的；不吉利的

optimally ['əptəməli] adv.最佳；最适宜地

panic ['pænik] n.恐慌，惊恐

pollen ['pɑlən] n.花粉

prednisone ['prednizəʊn] n.强的松

sinusitis [,sainə'saitis] n.鼻窦炎

spirometry [spai'rɔmitri] n.肺活量测定法

airway irritability 气道应激性，气道过敏性

airway obstruction 气道梗阻

bronchial asthma 支气管哮喘

bronchodilator 支气管扩张剂

peak expiratory flow rate (PEFR) 最大呼气流速

vocal cord 声带