Asthma is a chronic condition of the lungs where the swollen bronchial tubes (airways) cause a narrowing of the air passages resulting in difficulty in breathing.
During an asthma attack, muscles surrounding the airways in the lungs are tightened, resulting in limited airflow. Thick mucus is also produced during the attack and further blocks the air passages. When a person tries to breathe, air is forced through the narrowed bronchial passages and produces a wheezing sound.
Image source: National Heart, Lung and Blood Institute
Figure A shows the location of the lungs and airways in the body. Figure B shows a cross-section of a normal airway.Figure C shows a cross-section of an airway during asthma symptoms. A person suffering from an asthma attack may experience the following symptoms:
- Wheezing - a whistling sound that occurs during breathing.
- Coughing - tends to be recurring and worsens particularly at night or in the early morning, causing difficulty in sleeping.
- Chest tightness - patient will experience pressure on the chest.
- Shortness of breath - feeling out of breath.
Asthema can be life threatening if the symptoms are severe.
The fundamental causes of asthma are not completely understood. Asthma is believed to be triggered by a combination of factors such as:
- Inheritance of family genes
- Outdoor allergens (e.g. moulds, pollen and dust mites)
- Certain medications (e.g. aspirin, beta blockers)
- Smoke from tobacco
- Air Pollution
- Changes in weather and temperature
- Strenuous physical activities
- Emotional outbursts
Since asthma shares similar symptoms with other respiratory illnesses, such as emphysema, bronchitis, and respiratory infections, asthma is often not diagnosed. There are many who are unaware that they may be suffering from asthma for years. Most of them are usually under the impression that they are merely experiencing recurring coughs which occurs often at night, having difficulty breathing properly when they feel cold or experiencing severe panting after a strenuous session of exercise. When assessing if a patient is suffering from asthma, the doctor will refer to the patient’s medical history, laboratory test results such as spirometry (a method of measuring the amount of air inhaled and exhaled), peak flow monitoring (a method of measuring the amount of air a patient can exhale) and physical examinations such as X-rays, blood or allergy tests.