Asthma is a chronic, inflammatory lung disease involving recurrent breathing problems. The characteristics of asthma are three airway problems:
Asthma may resemble other respiratory problems such as emphysema, bronchitis, and lower respiratory infections. It is under-diagnosed - many people with the disease do not know they have it. Sometimes the only symptom is a chronic cough, especially at night, or coughing or wheezing that occurs only with exercise. Some people think they have recurrent bronchitis, since respiratory infections usually settle in the chest in a person predisposed to asthma.
The basic cause of the lung abnormality in asthma is not yet known, although healthcare professionals have established that it is a special type of inflammation of the airway that leads to:
- contraction of airway muscles
- mucus production
- swelling in the airways
It is important to know that asthma is not caused by emotional factors - as commonly believed years ago. Emotional anxiety and nervous stress can cause fatigue, which may affect the immune system and increase asthma symptoms or aggravate an attack. However, these reactions are considered to be more of an effect than a cause.
Some scientists theorize that the decline in serious illness may be one factor in the increase of allergic asthma. They believe it is possible that an under-utilized immune system may overreact to lesser irritants, inappropriately triggering the release of histamine and other inflammatory substances in the lungs.
Other researchers believe that the increased amount of time children are spending indoors is increasing their exposure to carpeting and other allergen-triggers.
Although anyone may have an asthma attack, it most commonly occurs in:
- children and adolescents ages 5 to 17 years
- adults older than 65
- people living in urban communities
Other factors include:
- family history of asthma
- personal medical history of allergies
Children most susceptible to asthma attacks include the following:
- children with a family history of asthma
- infants and other young children who when they develop a respiratory infection, they also tend to have wheezing
- children who have allergies
- children who have exposure to tobacco smoke and other allergens prior to birth
People with asthma have acute episodes when the air passages in their lungs get narrower, and breathing becomes more difficult. These problems are caused by an oversensitivity of the lungs and airways.
- Lungs and airways overreact to certain triggers and become inflamed and clogged.
- Breathing becomes harder and may hurt.
- There may be coughing.
- There may be a wheezing or whistling sound, which is typical of asthma. Wheezing occurs because:
- muscles that surround the airways tighten, the inner lining of the airways swells and pushes inward.
- membranes that line the airways secrete extra mucus.
- the mucus can form plugs that further block the air passages.
- the rush of air through the narrowed airways produces the wheezing sounds.
To diagnose asthma and distinguish it from other lung disorders, physicians rely on a combination of medical history, physical examination, and laboratory tests, which may include:
- spirometry - a spirometer is a device used by your physician that assesses lung function. Spirometry, the evaluation of lung function with a spirometer, is one of the simplest, most common pulmonary function tests and may be necessary for any/all of the following reasons:
- to determine how well the lungs receive, hold, and utilize air
- to monitor a lung disease
- to monitor the effectiveness of treatment
- to determine the severity of a lung disease
- to determine whether the lung disease is restrictive (decreased airflow) or obstructive (disruption of airflow)
- peak flow monitoring (PFM) - a device used to measure the fastest speed in which a person can blow air out of the lungs. During an asthma or other respiratory flare up, the large airways in the lungs slowly begin to narrow. This will slow the speed of air leaving the lungs and can be measured by a PFM. This measurement is very important in evaluating how well or how poorly the disease is being controlled.
- chest x-ray - a diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- blood tests - to analyze the amount of carbon dioxide and oxygen in the blood.
- allergy tests