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Asthma makes breathing difficult. It affects over 330 million individuals worldwide and causes approximately 1000 deaths daily, according to the Global Asthma Report 2018. In Hong Kong, about 10% of children and 5% of adults are asthmatic, which means more than 330,000 citizens suffer from it.
Asthma is a common chronic respiratory condition caused by inflammation. The inflamed airway becomes hyper-responsive to triggers. The muscles surrounding the airways subsequently tighten up, resulting in narrowing and swelling of the air passages. The inflammation also stimulates sticky mucus secretion. Airflow is therefore impeded, which leads to wheezing, breathlessness, coughing and tightness in the chest.
Asthma can develop at any age and often starts in early childhood. It is reported that around 50% of patients have experienced symptoms of asthma before the age of 10. More boys are affected during childhood, while it is more prevalent and severe in adult women.
Despite remaining an incurable disease, asthma can effectively be controlled by drugs and other forms of management. Airflow obstruction is reversible either with medication or sometimes occurs spontaneously.
There are two main types of asthma:
Asthma can also be classified into other types, for instance:
The clinical features of asthma vary by time, frequency and intensity. They can start gradually or come on as an attack.
What causes asthma is unknown; however, some environmental and genetic factors may be involved. It is important to identify your personal triggers and avoid them.
Your doctor may diagnose asthma by reviewing your medical history. Having allergic conditions such as eczema and hay fever, or having a family history of those conditions or asthma increases the probability. You may be asked to describe your symptoms, time of onset, possible triggers, other medical issues and current medication.
Physical examination is performed to
Several diagnostic tests are useful in measuring how well your lung functions.
Other tests include
Although there is no known cure for asthma, it can be effectively managed. Treatment plans change over time depending on the severity of the asthma, the response to treatment and the level of control.
Most medications are delivered by inhalation, allowing drugs to directly reach the affected site and be maximally effective with fewer systemic side effects. In severe cases, patients may need both oral and inhaled medication.
Long-term controllers
These are types of medication that are taken every day to reduce airway inflammation, thereby keeping symptoms and asthma attacks at bay.
1. Inhaled corticosteroids
They are the first-line anti-inflammatory medication used in the long-term control of asthma. It is important to note that the response to inhaled steroids will not be immediate and may take from a few days to a few weeks to be evident.
One common side effect of these inhalers is oral candidiasis (thrush), it can be avoided by using a spacer device to deliver the medication from your inhaler, or by rinsing your mouth with water, then gargling and spitting out after each dose. It is reported that chronic use may slightly stunt growth in children.
Examples: beclomethasone, fluticasone, budesonide.
2. Long-acting beta-agonists (LABA)
These are long-acting bronchodilators that help reduce symptoms by opening tight airways. LABA should not be regularly used by themselves but are useful when combined with inhaled corticosteroids. They should not be used for an asthma attack as they do not act quickly enough and are associated with severe asthma exacerbations.
Examples: formoterol, salmeterol and vilanterol.
3. Leukotriene modifiers
These types of oral medication open up the airways by counteracting the effects of leukotriene, an inflammatory chemical which causes smooth muscle contraction. Some are available in the form of chewable tablets.
Examples: montelukast and zafirlukast.
4. Theophylline
This medication relaxes smooth muscles around the airways and reduces inflammation. It is rarely used nowadays, as newer treatments are more effective and have fewer side-effects. Do not crush or chew the tablet if it is a sustained-release formulation.
5. Anticholinergics
These are inhaled bronchodilators, mainly prescribed as an adjunctive treatment for severe asthma. Common side-effects are dry mouth and dizziness.
Examples: tiotropium and ipratropium.
6. Mast cell stabiliser
They block the release of histamine, which causes a number of the symptoms of inflammation. Example: cromolyn sodium.
7. Immunomodulators
They are administered by injection to reduce the immune system’s overreaction to allergens. You may need biologics if you have moderate to severe allergic asthma. Examples: omalizumab and mepolizumab. 8.
8. Combination inhalers
Some patients may find combination inhalers convenient to use as they contain both an inhaled corticosteroid and a long-acting beta-agonist.
Examples: Seretide, Symbicort and Relvar Ellipta.
Short-term quick relievers
There are rapid rescue medications for acute asthma and prevention of exercise-induced asthma. You should carry them with you at all times.
1. Short-acting beta-agonists (SABA)
They promote bronchodilation in just a few minutes to provide fast relief. Children aged 5 or under usually take only SABA to treat wheezing.
SABA can be administered by a nebuliser that creates a mist for breathing in the medication through a mask or mouthpiece. You can also take them using an inhaler with or without a spacer.
Examples: salbutamol, terbutaline
2. Oral and intravenous corticosteroids
These are used for the short-term treatment of severe asthma. Long-term consumption may cause an array of side effects, such as loss of bone density, skin thinning and bruising and redistribution of body fat. However, they can be safe and highly effective when used for rapid control of a severe asthma exacerbation.
Examples: prednisone and methylprednisolone.
3. Short-acting anticholinergics
These are generally less effective than SABAS but are useful for patients who cannot tolerate SABAs.
Immunotherapy
Also known as allergy shots, immunotherapy works to reduce the overactivity of the immune system towards allergens. They help patients with allergic asthma.
According to the Global Initiative for Asthma (GINA), your asthma is considered uncontrolled if you have experienced, in the past 4 weeks, at least 3 of the following:
If you found that you are experiencing 3 or more of these symptoms, it is time for you to visit your doctor to review and step up treatment.
An asthma action plan is a unique written plan prepared by your doctor with your participation. The asthma action plan teaches you
There are several things you can do to improve asthma control.
For eligible persons with a HKID card, the cost for specialist outpatient services in public hospitals is $135 for the first consultation and $80 per subsequent consultation. Each drug item costs $15.
For non-eligible persons without a HKID card, the cost for attending specialist outpatient clinics is $1190 per attendance in public hospitals.
Beware of waiting times which can be very long in the public sector. For details, call the Hospital Authority at 2300 6555.
Fees will vary according to the condition of the patient, doctor fees, medication fees, and administration fees of each hospital or clinic. It is best to first consult your doctor and discuss the options suited to your situation. Our research found that the general consultation fee of visiting a Respiratory Medicine specialist ranges from $400 to $1800, excluding drug charges.
*All amounts are in HKD and were last updated in June 2020. No responsibility is accepted for any inaccuracies, errors, or omissions. It is always best to call ahead to make sure the information is still up-to-date.
Symptoms of asthma can start gradually or occur as an attack, they include: chronic or regular cough, wheezing, chest tightness, shortness of breath and increased mucus production in airways.
Allergic asthma and non-allergic asthma are the two main types of asthma, among other classifications such as occupational asthma, seasonal asthma and exercise-induced asthma.
Oral and inhaled medications are commonly used to manage asthma. Medications can be divided into short-term quick relievers and long-term controllers and are taken depending on the severity of asthma, response to treatment and level of control.
Triggering factors of asthma may differ among individuals. Some common triggers are air pollutants, cigarette smoke, inhaled allergens, cold air, exercise, medication and emotions.
Dr. Sarah Borwein is a Canadian trained General Practitioner who co-founded the Central Health Group and has been practicing family medicine in Hong Kong for over 15 years. After obtaining Certification in Family Medicine from the College of Family Physicians of Canada, she completed a Masters degree in Infectious Diseases from the London School of Hygiene and Tropical Medicine. She worked as a staff physician at the Beijing United Family Hospital where she was Director of Infection control during the SARS outbreak in China. A French speaker, Sarah is the advising and referral doctor for the French Consulate in Hong Kong. She is the site director for GeoSentinel (an international disease surveillance network) in Hong Kong and is past President of the Asia Pacific Travel Health Society. In addition, she sits on the Centre for Health Protection's Scientific Committee on Vector-borne Diseases, which advises the Hong Kong Department of Health on this type of illness.
This article was independently written by Healthy Matters. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.
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