Asthma

Asthma

It is a lung disease that affects approximately millions of people in world. In people with asthma, the airways of the lungs are hypersensitive to irritants such as cigarette smoke or allergens. When these irritants are inhaled, the airways react by constricting or narrowing.

Some people with asthma have only mild, intermittent symptoms that can control without drugs. In others, the symptoms are chronic, severe and sometimes life threatening. Although researchers have learned more about the underlying causes of asthma in recent years, a definitive treatment is still unavailable. In the last decade, asthma deaths worldwide have rose 42%. The reasons for this increase are not clear; however, many experts believe that the lack of standard treatments and the inconsistent monitoring of asthma patients have contributed to the increased mortality rate.

Mechanism of Development of Asthma

Many questions appears in our mind that what is asthma, what are the symptoms and causes, how is it diagnosis, what are the treatments, how is it prevented and maintained. Asthma is sometimes referred to as a disease of “twitchy lungs”, which means that the airways are extremely sensitive to irritants. The airways are the tubes that bring air from the windpipe (trachea) to the lungs. These tubes are called the bronchi. Each bronchus, in turn, branches into smaller tubes called bronchioles. At the end of the bronchioles there are small, balloon like structures called alveoli. The alveoli are tiny sacs that allow oxygen to diffuse from body tissues into the lungs to be exhaled. During an asthma attack, the bronchi and bronchioles constrict and obstruct the passage of air into the alveoli. Besides constricting, the airways may secrete copious amounts of mucus in an effort to clear the irritation from the lungs. The airway walls also swell, causing inflammation and further obstruction. As the airways become increasingly obstructed, oxygen cannot reach the small air sacs; blood levels of oxygen drop, and the body’s tissues and organs become oxygen deprived. At the same time carbon dioxide cannot escape the small air sacs for exhalation; blood levels of carbon dioxide increase, and exert a toxic effect on the tissues and organs of the body.

Causes of Asthma

Most of the time asthma is caused by, inhaling an allergen that sets off a chain of reactions. “Once asthma is present, symptoms can be set off or made worse if the patient also has rhinitis (inflammation of the lining of the nose)’’ or Acid reflux. A viral infection of the respiratory tract, aspirin, and a drug called beta-blockers (often used to treat high blood pressure e.g. Propanolol) can also inflame an asthmatic reaction. In addition to cigarette smoke and various allergens triggers can cause asthma attacks. Cold or other upper respiratory infections may bring on an asthma attack. Strong emotions, such as excitement, tension, or anxiety, may trigger asthma symptoms. Even exercise and extreme weather conditions, such as very cold, very hot, or very humid weather, can cause an asthma attack. Environmental exposures, such as pollution and ozone levels can also contribute to an asthma attack.

Sign and Symptoms of Asthma

The characteristic sign of asthma is wheezing, the noisy, whistling breathing that a person makes as he or she tries to push air in and out of narrowed airways. Other symptoms of asthma include a tight chest, shortness of breath, and a cough.

Diagnosis of Asthma

When diagnosing a patient for asthma, the examiner should look for maximum chest expansion while taking in air. Hunched shoulders and contracting neck muscles are other signs of narrowed airways. Nasal polyps or increased amounts of nasal secretions often noted in asthmatic patients. Skin changes, like atopic dermatitis or eczema, are a tip off that the patient has allergic problems. Inquiring about family history of asthma or allergies can be a valuable indicator of asthma.

The diagnosis may be strongly suggested when typical symptoms and signs are present. A test called spirometry measures how rapidly air is exhaled and how much is retained in the lungs. Repeating the test after the patient inhales a drug that widens the air passages (a bronchodilator) will show whether the airway narrowing is reversible, which is a very typical finding in asthma. Often patients use a related instrument, called a peak flow meter to keep track of asthma severity at home. Often, it is difficult to determine what is triggering asthma attacks. Allergy skin test may be used, although an allergic skin response does not always mean that the allergen being tested is causing asthma. Also, the body’s immune system produces antibody to fight off that allergen, and the amount of antibody can be measured by a blood test. This will show how sensitive the patient is to a particular allergen. If the diagnosis is still in doubt, the patient can inhale a suspect allergen while using a spirometer to detect airway narrowing. Spirometry can also be repeated after a bout of exercise if exercise induced asthma is a possibility. A chest x-ray will help rule out other disorders.

Treatment of Asthma

Currently, several drugs are used to treat asthma. Not all asthmatic drugs should be used by every asthma patient. Some patients with mild asthma only need to use medication intermittently to control wheezing. Patients with more serious asthma need to take medication at regular intervals to avoid life-threatening attacks. It is important for asthma patients to see their doctors if the frequency or severity of their symptoms change.

One form of medication is termed bronchodilators. Bronchodilators dilate constricted lung airways by relaxing the muscles, which line the bronchial tubes.Oral bronchodilators include theophylline; theophyllines counterpart, aminophylline, is used through a needle in the vein for severe episodes of asthma. During severe, acute attacks of asthma, injections of epinephrine are given just under the patient’s skin. Epinephrine has a quick, but short lasting effect of bronchodilation. Most asthma patients are given bronchodilators such as abuterolthat are used in a mist form that is inhaled from either a special inhaler device or an aerosol machine. Some patients are instructed to use their bronchodilator at regular intervals, while others may just be told to use the inhaler if they notice the beginning of an asthma attack. The inhaled medications are quick acting because they are directly applied to the constricted airways.

Another type of treatment is called Anti-Inflammatory drugs. Anti- Inflammatory drugs reduce the swelling and inflammation of the airways. These drugs can be inhaled or taken in pill form.

In fact, short courses of steroids are preferred. These “steroid bursts” are given over about a week’s time and then discontinued, as a treatment for a sudden sever asthma attack, perhaps brought on by exposure to an allergen or viral infection. Inhaled corticosteroids have few side effects. These medications are also prescribed for allergy patients. Unlike their oral counterparts, these drugs can be taken for much longer periods of time. They are especially useful in controlling moderate asthma.

A new asthma medication called leukotriene receptor antagonists (LTRAs) are being used to interfere with the actions of a class of chemicals called leukotrienes. Leukotrienes help produce the symptoms of asthma. Interference with their actions decreases asthma symptomology. LTRAs are believed to greatly reduce asthma severity, when taken daily. To avoid attacks patients can take certain preventative steps.

Asthma can be avoided by doing the following:

1. Avoid being outside during the early morning and late afternoon hours, when pollen levels are highest.

2. Since dust has been associated with asthma attacks, thoroughly and frequently clean the indoor environment. Dust and vacuum everyday. Wash bed linens in hot, soapy water every few days or so. Replace air filters in air conditioners and furnaces regularly.

3. During hot weather, use air conditioning. Eliminating the irritant is the key. If asthma is brought on by cigarette smoke, the patient must avoid this irritant. If asthma is brought on by exercise, the person should try to find a level of exertion that is comfortable. Using an inhaled bronchodilator before exercising may also control asthma symptoms.

4. For all persons with asthma, communication with and regular visits to their physicians are essential components of treatment. Without periodic checkups, the physician cannot monitor progress or potential worsening of symptoms. So, the most important aspect of prevention and treatment for asthma patients is the regular physician visit.

By 

Shahnawaz Daud

Batch 36