one of the most common problems in Singapore..let's take a more in-depth look at it!
What is Asthma?
Asthma is a disorder of the respiratory system, which causes inflammation of the airways. This leads to constriction and swelling of airways, causing difficulty in breathing.
What is the mechanism behind an asthma attack?
An asthma attack has 2 main components - airway irritation and swelling (inflammation) and tightening of the muscles surrounding the airways (bronchoconstriction).
- In asthma, inhalation of certain substances (eg, pollen, smoke particles, cold air) causes the smooth muscle (outermost muscle) of the airway to spasm (contract), thus narrowing the airway.
- The middle layer swells because of inflammation
- More mucus is produced which clogs the airways
- All of these effects reduce the diameter of the airways.
Analogy time!
To visualize the mechanism of airway obstruction, imagine looking through a tube where you can see out to the other side.
When an asthma attack occurs, one of the first reactions that the airway contracts. Imagine the garden hose contracting, and imagine the visible world on the other end of the hose narrowing. Think of that reduced visual field as representing less oxygen getting into the lungs.
The second reactions is swelling (from the inside). The interior muscles of the airway swells. Imagine the hose as thicker on the inside. So now, we have a narrower hose from constriction, and obstruction occuring within the hose from swelling, both narrowing the the visual field in the hose as we look out to the other end. The same thing occurs in the airway during an asthma attack - air flow is reduced further, from the action of two obstructive mechanisms.
(Medical knowledge here! Read on if you want more info) This swelling occurs because, in reaction to some stimulus that may be localized in the upper airway, the offended area is now being bombarded by white cells called mast cells (eosinophils and basophils)These cells release Histamine..Histamine causes the affected tissue to swell. Histamine when released is the primary cause of all "swelling."
Lastly, there is mucus production. which narrows our visual field through the garden hose almost completely. Imagine the hose being filled with..well, mucus. When we can't see through the hose to the other side, that symbolizes the reduction of air flow in the patient with asthma and the decreasing amounts of oxygen that are getting to the lungs.
How do Relievers Inhalers work?
The drug in a reliever inhaler relaxes the muscle in the airways. This opens the airways wider, and symptoms usually quickly ease. These drugs are called bronchodilators as they dilate (widen) the bronchi (airways).
(yes, there are that many different inhalers!)
So...what's the difference between Reliever Inhalers, and Preventive Inhalers?
Reliever inhalers are used when an asthma attack happens, and you need a fast acting medicine. Unless medicine in tablet form, the drug in the reliever inhaler goes straight to the airway, thus making the effect much faster and stronger.
For Preventive Inhalers, these are taken every day to prevent symptoms from developing. The type of drug commonly used in preventer inhalers is a steroid. Steroids work by reducing the inflammation in the airways. When the inflammation has gone, the airways are much less likely to become narrow and cause symptoms such as wheezing.
(anyone got the joke? :D)
tadaaaa! hope you didn't die from information overload! :D feel free to click on the below links (credits) for even more information :D
