Asthma
Asthma is a common and often complicated disease that affects about 3 million Canadians, and about 130 million people worldwide. This chronic lung disease can range in severity, from very mild, occasional symptoms, to recurrent and life-threatening attacks. The cause of asthma is unknown, but is thought to be related to a complex interaction of environmental factors, such as pollution smog, and allergies, as well as exposure to tobacco, some animals, and chemicals. Asthma often runs in families so there may genetic factors as well. Asthma is closely related to seasonal allergies, with people often experiencing both conditions. Research is currently underway to further determine the relationship between allergies and asthma.
Asthma is generally defined as a chronic inflammatory disease of the airways in the lungs. Like other chronic diseases, it has no real cure. However, asthma can be well controlled through medication, control of asthma "triggers", and close monitoring of symptoms. The main mechanism at work in asthma is inflammation, which in turn causes narrowing of the airways, resulting in obstructed flow of air. The inflammation also causes spasm of the airways, further increasing air flow obstruction. Treatment focuses on reducing the inflammation, and to a lesser extent, decreasing airway spasm.
Triggers for asthma are environmental factors that can "trigger" the inflammation and spasm associated with asthma. Individuals have different triggers, with mould, pollen, animal hair/dander, tobacco, and air pollution among the most common. Part of controlling asthma is learning what your triggers are, and avoiding them. For example, if smog or poor air quality triggers your asthma, staying indoors on hot humid days when the air quality index is poor, is recommended. Sometimes common cold viruses can trigger asthma. Some athletes experience exercise induced asthma.
Diagnosis of asthma can be difficult and challenging, with symptoms ranging from frequent coughing, wheezing, and shortness of breath, to chest tightness, and exercise intolerance. People often associate asthma with wheezing alone, but not everyone who wheezes has asthma, nor does all asthma have wheezing as a symptom. Diagnosis of asthma is made on the basis of symptoms, known triggers, family history, and physical assessment. The most important test in diagnosing asthma is called spirometry. This breathing test measures how much air you have in your lungs, and how hard you can exhale this amount of air. Other diseases of the lung are ruled out using x-rays and other lab tests. Diagnosis of asthma in children is even more challenging. Children under age 5 cannot reliably perform spirometry testing. Many of the common childhood viral diseases cause coughing and wheezing, mimicking asthma symptoms.
The mainstay of medical treatment is the use of inhaled corticosteroids, which act to reduce the inflammation in the disease. These inhaled steroids are sometimes called "preventers" or "controllers" because they are used over longer periods of time to reduce the incidence and severity of symptoms. Another important group of medications are inhaled bronchodilators, which act by reducing the spasm of the airways, thereby improving airflow. These inhalers, such as ventolin, are often called "relievers" or "rescue" medications because they are usually short-acting, and are intended for use when symptoms become frequent or severe. Sometimes longer acting bronchodilators are combined with inhaled steroids for improved asthma control.
Well controlled asthma means there are no symptoms throughout the day or night, use of the "reliever" medication is less than four times a week, and there is no asthma related school or work absence. If this is not the case, asthma is not well controlled. Good control is confirmed by spirometry. If a person with asthma is having severe symptoms such as severe shortness of breath, wheezing, or coughing, which is not relieved by the reliever or rescue inhalers, the person should call 911 and to go an emergency department, since acute asthma attacks can be quite severe, even life-threatening.
Critical to good management of asthma is developing an asthma action plan that addresses asthma education, identifying and controlling triggers, monitoring of symptoms, and proper use of medications. A downloadable asthma action plan is available on the Asthma Society of Canada website at www.asthma.ca which is also an excellent resource for information on all aspects of asthma. They can be reached by phone at 1-866-787-4050.