Asthma is an obstructive disease of the respiratory tract involving the small airways of the lung. When a patient with asthma is exposed to an allergen, the muscles of small airways get inflamed, which result in its narrowing. The inflamed muscles of airways secrete mucus which further obstructs breathing.
About 25% of Indian population suffer from asthma. Asthma can be a major issue and can interfere with the day to day activities of the patient. There is no complete cure for asthma, but its symptoms can be controlled with the help of medication.
Signs and Symptoms of asthma
Asthma can be triggered by factors such as cold air, pollen grains, dust, animal fur, smoke and emotional stress. The trigger for asthma varies from patient to patient. When the patient with asthma comes in contact with its trigger factor, narrowing of airways occur which may result in symptoms such as
- Shortness of breath
- Chest discomfort
- Difficulty in sleeping
Diagnosis of Asthma
If you experience any of the symptoms of asthma, consult a doctor. After taking a complete medical history and physical examination, your doctor may ask you to take the following tests to assess the severity of asthma
Allergy tests: These tests can find out of the specific allergen that may be causing your asthma symptoms. Allergy can be tested using skin and blood tests. Skin allergy tests are most commonly recommended. In this test, you would be getting a small dose of the possible allergen and then your body’s immune response to the allergen will be studied.
Lung function tests:Lung function tests are performed to assess the functioning of the respiratory system. These tests are generally performed before and after using anti-asthma medication. Following are the most commonly prescribed lung function tests:
Spirometry: Spirometry detects asthma by measuring the rate and amount of air you can breathe in and out. During this test, you would be asked to take deep breath and exhale forcefully into a mouth piece of spirometer. Spirometry detects asthma by measuring the following parameters:
- Forced expiratory volume in one second (FEV1) – It refers to the maximum amount of air a person can exhale forcefully in one second. The person with asthma has a lower FEV1 when compared to a healthy person.
- Expiratory forced vital capacity (FVC) – It is the total amount of air which can be forcibly exhaled in one breath.
- FEV1/FVC ratio – It is the ratio of amount of air exhaled in one second (FEV1) to the total amount of air that can be forcibly exhaled in one breath (FVC). If the FEV1/FVC ratio is lower than normal, it indicates the presence of asthma.
Peak air flow meter: Peak airflow meter assesses how fast the air comes out through your airways when you exhale forcefully after inhaling fully. It is a portable device into which you have to exhale the air forcefully, through its mouthpiece. Measuring the peak flow rate using this meter helps you in managing the symptoms and preventing the attack of asthma.
Refer the following table to know how to interpret your peak flow:
|Peak flow rate||Interpretation|
|80 – 100%||Asthma is under control|
|50 – 80%||Asthma is getting worse|
|Less than 50%||Indication of medical emergency|
Methacholine challenge: Methacholine is a drug that narrows airways and increases the difficulty in breathing. A patient who has asthma would react at the low doses of methacholine, which can be detected by spirometry. During methacholine challenge, you would be asked to inhale small doses of methacholine. Spirometry would be done before and after inhaling each dose. If there is no change in breath after the first dose, you would have to inhale increasingly larger doses of methacholine until a significant drop in the parameters of the spirometer is observed.
Imaging test: Imaging tests such as CT scan, radiology, and ultrasonography helps the healthcare provider to rule out the other conditions which may cause the symptoms of asthma.
Treatment of asthma
The common drugs prescribed to treat asthma include bronchodilators, anti-inflammatory drugs, corticosteroids and immunomodulators.
Prevention of asthma attacks
- Avoid exposure to allergens: Allergens would temporarily increase inflammation of airways. So, avoid exposure to allergens.
- Avoid smoking: Stay away from cigarette smoke as it worsens the symptoms of asthma.
- Take medicine regularly: Take your anti-asthma medication regularly as prescribed by your doctor.
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- What is asthma?. https://www.nhlbi.nih.gov/health/health-topics/topics/asthma/. Assessed on: 26/9/2017.
- Asthma diagnosis. http://www.aafa.org/page/asthma-diagnosis.aspx. Assessed on: 26/9/2017
- Asthma and allergies. http://www.webmd.com/allergies/asthma-allergies#1. Assessed on: 28/9/2017.