General · 15th October 2014
As we head into the winter months, colds and upper respiratory infections become more prominent. Asthma, a chronic respiratory disease also tends to flair.
Asthma is defined as a chronic inflammatory lung disease characterized by airway narrowing. This produces symptoms of cough, wheezing, shortness of breath and chest tightness. Asthma often occurs episodically, usually in response to a trigger. There are many things that can trigger an asthma attack. Examples are dust, mold, smoke, chemicals, and/or cold air. Regardless of the trigger, the resulting airway narrowing is partially or wholly reversible with treatment and/or removal of the trigger.
At the cellular level, asthma causes changes to the smooth muscle tissues in all the airways leading to (but sparing) the alveoli (where oxygen and carbon dioxide are exchanged). Changes include thickening of the basement membrane, loss of cilia (small hairs that line the upper airways and help to remove foreign particles and debris from the lung), swelling of the airways, smooth muscle thickening, and an increased collection of inflammatory cells that plug the airways. The resulting changes leads to airway narrowing, which produces the characteristic symptoms. Over time, poor asthma control will cause increasing damage to the airways as well as remodeling of the airways.
Asthma can develop at any age although most are diagnosed in childhood. The incidence is increasing and thought to be related to: (i) improved hygiene and less exposure to pathogens, which imbalances the normal immune response (ii) increased indoor air pollution brought on by energy efficient built homes, recycled air with chemicals and allergens (dust, mold) (iii) increased incidence early onset viral respiratory conditions (iv) congenitally small lungs due to maternal smoking in pregnancy (v) increased awareness and diagnosis.
Some individuals are more at risk for developing asthma. During childhood, males are more at risk than females. This often reverses in adulthood. Urban dwellers are more likely to be asthmatics than those living in a rural location. As your income lowers, your risk of developing asthma rises. A family history of asthma, atopic dermatitis and eczema, or allergic rhinitis increases one risk as well as workplace or home exposure to tobacco or chemical irritants. Infants with exposure to high levels of antigens such as dust mites are also at increased risk.
Asthma affects 13% of Canadian children and is a major cause of hospitalization and emergency room visits. Each year in Canada, 20 children and 500 adults die as a result of poor asthma control. It is the leading cause of lost days of school and learning. It is the third leading cause of lost workdays for adults.
A diagnosis of asthma is based on history, physical symptoms and a special set of breathing tests done in the hospital setting called spirometry. Spirometry can only be done with children over the age of five. Spirometry measures the amount of air that an individual can inhale as well as how well they can exhale the air over time. This is compared to known normal values for age, height and weight. Testing is usually done before and after taking asthma medication. This confirms that the airways are narrow and medication causes reversal.
80% of asthmatic children develop symptoms before the age of five. Cough is often a tell tale sign, particularly worsening at night, in response to certain irritants, or during certain seasons. Ongoing or frequent upper respiratory infections may also occur. Wheezing may or may not be present. Wheezing is a high-pitched sound that occurs when air is forced past narrow airways. It will vary in pitch depending how far down the airways are narrowed. Wheezing can occur in inspiration (breathing in), expiration (breathing out), or with both. Both cough and wheezing may increase when the individual has a cold, with weather changes, stress, with exposure to irritants such as dust, mold, animal dander, and/or exercise.
Allergy testing is sometimes useful to determine causation. In younger children, food allergies and eczema are often more common whereas in older children allergic rhinitis prevails.
Asthma treatment is individualized according to symptoms, degree of impairment, and triggers. While some people are affected daily, others may be symptomatic only on occasion. Some people have mild symptoms, others more severe.
Medication for asthma is divided into two classes or groups, a RELIEVER medication and a CONTROLLER medication. Anyone with asthma should carry a reliever or ‘rescue’ medication for use when symptomatic. Examples of this include ventolin or salbutamol. These are the so-called bronchodilators because they help to relax the muscles that narrow the airways. Reliever medication provides relief within 10-15 minutes, but the effect will only last for up to four hours. The side effect of the rescue inhalers includes headache, shaky hands, nervousness, and increased heart rate.
Controller medications are those medications that help control airway inflammation, reduce mucous production, and/or make the airways less sensitive to triggers. These require regular daily use or daily seasonal use when triggered. There are three main types of controllers: (i) Corticosteroids: There are many different types on the market but they all work the same way. Examples are Flovent, beclomethasone, and memetasone. Each is taken daily or twice daily. They can be taken the same time as the rescue inhaler. These medications work more effectively over time and thus their effect may take days to be noticed. Steroid medication can cause a sore throat, hoarse voice or an oral yeast infection. Any one using a steroid inhaler needs to rinse their mouth with water following inhaler use. (ii) Leukotriene receptor antagonists (LRTA’s): The Canadian version is called Montelukast or Singulair. This is taken in pill form, usually once daily. It works by decreasing the number of pro-inflammatory agents that cause the inflammatory response at the cellular level. (iii) Long acting beta 2 agonists (LABA’s): Rarely taken alone, these medications help dilate the airways for up to 12 hours. Usually prescribed along with corticosteroid and rescue inhaler. Examples include fomoterol or salmerterol.
Most asthma medication comes in four different delivery systems: multi-dose inhaler (MDI), discus, turbuhaler, and nebulizer. All deliver the rescue medication or controller by inhalation into the lungs. The exception to this is Montelukast, which is a tablet.
MDI has many doses in the canister and releases the medication in an aerosolized solution. It can be used alone or with a spacer. One MDI has up to 60 doses per canister. Ventolin or salbutamol is always in an MDI, light green/blue in colour.
It is recommended that both adults and children use a spacer for use with the MDI as research has shown that more medication is inhaled when it is used. This is particularly true for children. A spacer is a small hollow cylindrical device that attaches to the MDI. It allows for greater control.
Both the discus and the turbuhaler, once primed, release a powder that is inhaled into the lungs through the mouth.
For some individuals, and often in the emergency setting, the medication is in liquid form. This is put into a container, and oxygen or air is piped into the container, turning the medication into a mist that is inhaled by the individual. This is termed a nebulizer.
Asthma medications can be combined into one canister or discus so that they are delivered together. An example of this is Advair, which combines the rescue and controller medication together.
It is very important that those who have asthma are taught how to use the medication forms. Many asthma attacks worsen because of incorrect technique.
For most individuals, when a diagnosis of asthma is suspected, medications are trialed to obtain sustained relief and control. Medication is added in a step-wise fashion until this occurs. Spirometry is carried out as confirmation.
As noted, treatment is individualized according to triggers and symptoms. For some, avoidance of triggers may be enough, with use of reliever in case of contact with the trigger. For others, contact may produce more lasting effects, there may be multiple triggers, and a controller medication may need to be added. Some individuals need a controller medication on a regular basis, others only at certain times.
For those who use controller medications when needed, asthma tends to flair with trigger exposure, or when ill, particularly with a cold. When this occurs, it is important to start using the controller medication right away until asymptomatic. I always recommend taking the controller medication for a week longer once asymptomatic, to ensure that all inflammation at the cellular level has resolved.
Regardless, all individuals with asthma should have a current rescue inhaler prescribed to them for use when needed.
There is no research that demonstrates that one steroid product is more superior to another. Most of the steroid medications have been well studied over the years and there is no research that suggests that they are harmful to children when given over a long period of time.
Asthma is a chronic disease, which means there is no cure. Some children do outgrow their asthma as they age, or find that it becomes less severe. Good asthma control involves proper use of medication, symptom monitoring, control of triggers, and an ongoing relationship with a health care professional.
Signs of good asthma control include the ability to do all normal activities, including exercise, without symptoms, no cough or wheeze at night, no trouble sleeping at night, and no absenteeism from work or school.
Signs of worsening control include the use of reliever medication more than three times per week (other than for use prior to exercise), or use of an entire canister of reliever medication over one month’s time.
One tool used to monitor symptoms is the use of a peak flow monitor. Similar, though less sophisticated than spirometry, the monitor is a small device that measures how well an individual is able to forcefully exhale. Done daily at home, a decreasing value suggests that airways are narrowing and may be the first sign of change before an individual becomes symptomatic.
All health professionals advocate for an asthma plan for each individual with asthma. This is a written plan, drawn up by both client and health professional, that documents regular medication use, signs and symptoms of worsening control, and what to do when this occurs. It is practical in that it is a written plan to refer to when changes occur, and can easily be copied and shared with others, such as teachers or sport coaches. Research has shown that those with asthma plans have greater control of their asthma, have less severe attacks, and are less likely to end up in the emergency room or be hospitalized.
If you currently do not have an asthma plan, consider making an appointment with a health care professional to discuss this.
Any individual with asthma should get the flu vaccine annually as a preventative measure. Similarly, all adults over the age of 55 should receive a one time pneumococcal vaccine, which helps to reduce the incidence of pneumococcal pneumonia.
There are many excellent resources on-line that can be downloaded for use. The Asthma Society of Canada has an excellent website that provides videos for instructions on inhaler use as well as peak flow. It also has a site devoted to children with games that help to explain an asthma diagnosis. The National Heart, Lung and Blood Institute and Emergency Medicine (Medscape) also have quality sites that tend to be a little more scientific but very informative.