Asthma
Perhaps the most commonly discussed respiratory disease after the common cold is asthma. The word asthma is derived from a Greek work meaning “breathlessness” or “panting”, both of which accurately describe an asthma attack. It is, however, not just another “breathing problem”. To physicians who treat asthma, it is a serious medical condition” untreated asthma can be fatal.
Asthma is a condition in which the airways of the lungs become either narrowed or completely blocked, obstructing normal breathing. This obstruction of the lungs, however, is reversible, either spontaneously or with medication. That is why asthma is technically called Reversible Obstructive Airway Disease (ROAD)
Air reaches the lung through the windpipe (trachea), which divides into two large tubes (bronchi), one for each lung. Each bronchi further divides into many little tubes (bronchioles), which eventually lead to tiny air sacs (alveoli), in which oxygen from the air is transferred to the bloodstream, and carbon dioxide from the bloodstream is transferred to the air.
Although everyone’s airways have the potential for constricting in response to allergens or irritants, the asthmatic’s airways may become obstructed by constriction of the muscles surrounding the airway or inflammation and swelling of the airway or increased mucus production which clogs the airway.
Once the airways have become obstructed, it takes more effort to force air through them and breathing becomes laboured. This forcing of air through constricted airways can make a whistling sound, called wheezing. Irritation of the airways by excessive mucus may also provoke coughing.
Because exhaling through the obstructed airways is difficult, too much stale air remains in the lungs after each breath. This decreases the amount of fresh air which can be taken in with each new breath, so not only is there less oxygen available for the whole body, but more importantly, the high concentration of carbon dioxide in the lungs causes the blood supply to become acidic. This acidity in the blood may rice to toxic levels if the asthma remains untreated.
Asthma episodes can be triggered by a variety of factors, most notably allergens, infections, environmental pollutants, and nonspecific stimuli such as exercise and emotional states.
Between 50 and 70 per cent of adults with asthma suffer from allergies. In children under three years of age, viral infections are likely to be the most common trigger. After three years, allergies also begin to play an increasing role as a trigger. After 20 years of age, occupational exposure to toxic substances and allergens also can be important triggers for asthma.
Common allergens associated with asthmatic responses are:
Foods: Nuts, peanuts, chocolate, eggs, citrus fruits, milk
Plants or plant products: Pollens, grasses, mold spores
Animal or insect materials: Dust mites, animal dangers, feathers, canine or feline saliva
Numerous scientific studies have shown that avoidance of specific allergens in patients with asthma who have been previously sensitized will result in improved asthma symptoms and decreased medication requirements.
Anatomy of an asthma attack
When the respiratory system is working properly, the air we breathe passes in and out of the lungs through a network of airways. But for people with asthma, even a minor irritant will set off an immune response that can shut down the airways.
Asthmatic symptoms are usually quite variable, someone with asthma may go for periods of time without symptoms, and then suddenly have severe episodes for days at a time. The most common symptom is wheezing.
Routine treatment for asthma includes inhaled bronchodilators, injected epinephrine (adrenalin), or intravenous theophylline.
Bronchodilators are drugs which open up or dilate the constricted airways.
Taking anti-inflammatory drugs, aimed at reducing asthma is a relatively new approach to treating asthma. The idea behind it is that if the underlying inflammation of the airways is reduced, the bronchi may become less hyperactive, making future attacks less likely.
For asthma which is strongly triggered by allergies, allergen avoidance can often greatly reduce the amount of medication needed to control the asthma. Taking anti-allergic medications or taking shots for allergy desensitization are other alternatives.
Bronchitis
Bronchitis is an inflammation of the bronchi, the large airways inside the lungs. (Bronchiolitis is the inflammation of the bronchioles, the small airways.) The inflammation causes these passages, or bronchial tubes, to increase their production of mucus that is thick and yellow or grey in color, which is then coughed up. Bronchitis may be either acute or chronic.
Symptoms of acute bronchitis include fever, chest pain, and a cough that brings up mucus. Acute bronchitis can be caused by a respiratory infection, such as a cold. It also can result from breathing irritating fumes, such as those of tobacco smoke or polluted air.
Doctors consider the condition chronic if such coughing lasts for several months in each of two or more successive years. Chronic bronchitis may produce shortness of breath and, in severe cases, heart failure. The most common cause of chronic bronchitis is cigarette smoking. Either type of bronchitis may lead to asthma or pneumonia.
Bronchitis may be treated with drugs that expand the bronchial tubes, or with compounds that loosen mucus so it can be coughed up more easily. Moist air also helps loosen mucus. Antibiotics are prescribed if a bacterial infection is present. Most cases of acute bronchitis clear up within weeks. Chronic bronchitis cannot be cured.
The doctor may recommend cough medicines, antibiotics and plenty of bed rest. Chronic bronchitis usually persists for long periods of time and occurs most often in heavy smokers or as the result of recurring episodes of acute bronchitis. If you have bronchitis and smoke, you should stop. Smoking puts you at risk of emphysema, a life-threatening disease that deteriorates the lungs.
An antibiotic or inhaler is often prescribed. Cough medicines should not be used with chronic bronchitis because coughing is the only way the lungs can get rid of the mucus.
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