Asthma Health Facts
Asthma is a chronic, recurring inflammatory condition of the respiratory system.
It is characterized by bronchial hyper-responsiveness, inflammation, increased mucus production and intermittent airway obstruction. Asthma is increasingly common and affects one in four urban children.
Asthma Risk Factors
The many risk factors of asthma include:
- male sex
- indoor/outdoor allergens
- certain drugs (eg, aspirin)
- occupational allergens
- viral respiratory infections
- low birth weight
- allergies to certain foods
- air pollution
The various categories of stimuli include:
- Allergenic air pollution
- Food allergies
- Fossil fuel-related allergenic air pollutions
- Industrial and other chemicals
- Childhood infections
- Allergenic indoor air pollution
- Hormonal changes during menstrual cycle
- Emotional stress
A sudden increase in symptoms is commonly referred to as an ‘asthma attack’. Shortness of breath (dyspnea) and wheezing are the clinical hallmarks.
Some victims in the late stages of an attack experience a persistent cough, with air motion becoming so impaired that no wheezing can be heard. When present, the cough sometimes produces clear sputum.
Signs of an asthmatic attack include:
- rapid breathing (tachypnea)
- prolonged expiration
- rapid heart rate (tachycardia)
- rhonchous lung sounds (audible through a stethoscope)
- over-inflation of the chest
In children, diagnosis is often based on the patient’s medical history and subsequent improvement with an inhaled bronchodilator medication.
In adults, diagnosis is made using a peak flow meter. This test measures lung capacity and the degree of restriction experienced.
It is helpful to test peak flow at rest and after exercise, especially in young asthmatics who may only suffer from exercise-induced asthma. If the diagnosis is inaccurate, a more formal lung function test is conducted.
In the emergency department, doctors may use capnography, which measures the amount of exhaled carbon dioxide along with pulseoximetry, which shows the amount of oxygen dissolved in the blood.
The 30-second Asthma Test is useful in assessing control and severity of asthma. It comprises the following questions:
- Do you cough, wheeze or have a tight chest because of asthma (> four days a week)?
- Does coughing, wheezing or chest tightness wake you up at night (> once a week)?
- Do you stop exercising due to asthma?
- Do you need to use your Blue inhaler more than three times a week?
If your answer is YES to any of the above, the asthma is not well-controlled.
Treatment depends on the severity and frequency of symptoms. Inhaled bronchodilators are recommended for short-term relief. For occasional attacks, no other medication is needed. For mild-persistent disease (more than two attacks a week), low-dose inhaled steroid, or alternatively, an oral leukotriene modifier, a mast cell stabilizer, or theophylline may be used.
For daily attacks, a higher dose of steroid in conjunction with a long-acting inhaled beta-2 agonist may be prescribed. Alternatively, a leukotriene modifier or theophylline may substitute the beta-2 agonist. Oral glucocorticoids may be added to these treatments during severe attacks.
- short-acting, selectivebeta-2 agonists like salbutamol and terbutaline. Cardiac side effects occur at higher doses.
- anticholinergic medications like ipratropium bromide. They have no cardiac side effects. However, they take up to an hour to achieve their full effect and are not as powerful as the beta-2 agonists.
Prevention agents include:
- inhaled steroids which come in the form of inhaler devices.
- leukotriene modifiers
- mast cell stabilisers
- antimuscarinics/anticholinergics, which have a mixed reliever and preventer effect. (These are rarely used in preventive treatment, except in patients who do not tolerate beta-2 agonists.)
- methylxanthines are sometimes used if sufficient control cannot be achieved with inhaled glucocorticoids and long-acting β-agonists alone.
- antihistamines are often used to treat allergic symptoms that may underlie the chronic inflammation.
Emergency treatments are available when an attack does not respond to the patient’s usual medication. These include:
- oxygen to alleviate the insufficient supply that results from extreme attacks
- nebulised salbutamol or terbutaline, often combined with ipratropium
- systemic steroids, oral or intravenous
Asthma Control And Management
The goals for asthma control are as follows:
- day-time symptoms not more than twice a week
- no limitation to physical activity
- no night-time symptoms
- not using relievers more than twice a week
- normal or near normal lung function
- no acute attacks