This is the difference between a normal and an asthmatic bronchiole. | (Drawing: Copyright © 2012, A.D.A.M., Inc.) |
For something as common as the breathing disorder asthma, there really is a knowledge deficit out there about it. Asthma is simply a disorder of the lungs in which both the large and smaller airways, swell and constrict the airways leaving the airways themselves feeling tight. For some, this is a simple inconvenience, and for others this can make it episodically impossible to make the bed, or walk from the car to the grocery store. Over time, a failure to treat asthma or to treat asthma correctly or fully, can result in a remodeling of the airways, and a permanent lifelong decrease in the ability of the lungs to provide adequate amount of oxygen to the patient, and to his heart.
In asthma, you have two processes going on. First, you have inflammation which is occurring in airways in response to allergens, and then you also have muscular constriction of the airways. The result is a decreased lumen in the airways. There is the sensation of difficulty moving air, particularly out, and there may also be wheezing. There is also a sensation of chest tightness and coughing as the swollen airway can be perceived in a sense, as a foreign body. Allergists can measure the level of airway impairment in pulmonary function testing, and to some degree using a pulse oximeter. Patients may also respond to asthma with a rapid heart rate. The worst cases may actually experience bluing of the nailbeds and lips.
Patients respond to many different things as allergens. Some patients have asthma which is triggered by dust and dust mites. Others by animal fur or animal dander. Mold and pollen are triggers for many. Some have something called exercise induced asthma, and have airways which clamp down when they need the air most. Cigarette and cigar smoke can also set off asthma. Many of us with asthma, are much more inclined to have an asthma attack during a respiratory infection than at any other time. There are also patients who have something called intrinsic asthma, which means they don't usually have asthma unless the mechanism is tripped by an ongoing infection they have, and may not know about. Some people, like myself, have asthma triggered simply by breathing in very cold or cold and dry air. Some are thrown into asthma attacks by the smell or inhalation of what might seem like a small amount of the fumes of deodorant, perfume, household cleaning chemicals, etc. Food allergies can also lead to mild or more serious asthma attacks. Asthma can also worsen in periods of time of emotional stress. I remember hearing that the only time in her life that my maternal grandmother had asthma, was during the London Blitz. She was very worried about relatives during the bombings, and a combination of the dust and stress caused asthma. After the war, her asthma disappeared and she never experienced it again. She passed in her late eighties of something else entirely. Asthma also can be familial, and it often occurs in families who have food allergies or eczema.
Asthma is not simply an inconvenience to people. Many deaths occur annually due to poorly controlled or undiagnosed asthma, in young people especially. Children naturally have smaller airways than adults and they can be much less tolerant of a rapid constriction of their airways. Asthma can also be a co-factor in sudden death for people with other medical issues. Asthma naturally impedes the amount of available oxygen to the heart at intervals, and for someone with coronary artery disease or for someone with a simple conduction disturbance of the heart unrelated to coronary artery disease, it can trigger problems in the heart also.
Long term incompletely treated asthma may not just lead to airway remodeling and an impairment of oxygenation in the long term. It may also lead to COPD or chronic obstructive pulmonary disease, of which emphysema is a feature. COPD causes a lot of deaths in the long term. It is often caused by smoking, but non-smokers with asthma can also develop it. Fortunately, we can intercede sufficiently now for a child with asthma to properly prevent COPD in their later life, if we treat their asthma in the long term, and if they avoid smoking.
For most people, asthma in a controllable issue, but it is not curable. Treatment is focused on two basic principles. 1. Decreasing the inflammation of the airways 2. Keeping the airways sufficiently dilated to do the job of air exchange without wheezing. Another goal is the prevention of airway remodeling which leaves the patient with diminished airway capacity forever. This is achieved in a number of ways. Many patients are given anti-allergy tablets such as Loratadine, or others. Another important strategy is inhaled steroids. These corticosteroids can be inhaled in the form of a small aerosol inhaler a couple of times a day. These can do the job of decreasing the inflammation in the lungs without providing all of the negative effects of steroids in tablet form. The next step is bronchodilators. A patient can be given an inhaler with medication which dilates the airways. Each patient has to have a personalized plan. Often an allergist immunologist can find the combination of drugs which best control the asthma of a particular patient, much faster than a family practitioner can. The strategy is to help the airways to "forget" that this clamping down and wheezing was ever a habit for them. Once this is done, the patient can theoretically go a long time without asthma symptoms and can be maintained on very little medication.
During asthma flares, which can occur during colds, flus, or other times, other medications can be added. Medications delivered via nebulizer can quell new inflammation or a new found propensity for wheezing. Medications delivered via nebulizer, often every 4-6 hours while the patient is awake, can be bronchodilators like the albuterol family. It can also be additional steroids, like budesonide. The worst cases may need a few days of oral steroids, but because this complicates treatment down the road, we all try to avoid this.
These are other medications which may be used to control asthma for some patients:
- Cromolyn. This medicine is taken using a device called a nebulizer. As you breathe in, the nebulizer sends a fine mist of medicine to your lungs. Cromolyn helps prevent airway inflammation.
- Omalizumab (anti-IgE). This medicine is given as a shot (injection) one or two times a month. It helps prevent your body from reacting to asthma triggers, such as pollen and dust. Anti-IgE might be used if other asthma medicines have not worked well.
- Inhaled long-acting beta2-agonists. These medicines open the airways. They might be added to low-dose inhaled corticosteroids to improve asthma control. Inhaled long-acting beta2-agonists should never be used for long-term asthma control unless they're used with inhaled corticosteroids.
- Leukotriene modifiers. These medicines are taken by mouth. They help block the chain reaction that increases inflammation in your airways.
- Theophylline. This medicine is taken by mouth. Theophylline helps open the airways.
Please take asthma seriously and have a battle plan for it, if you or a family member are afflicted. Although many have their first asthma episodes as children, it is possible to develop asthma or asthmatic bronchitis at any point throughout life. Worldwide, the incidence of asthma is increasing.
Please see my next post in this series on Asthma, which concerns actions which we can take to decrease asthma by making changes in our home environment:
http://rationalpreparedness.blogspot.com/2013/02/strategies-for-home-asthma-proofing-or.html
Read more about it at:
http://www.nhlbi.nih.gov/health/health-topics/topics/asthma/
http://en.wikipedia.org/wiki/Asthma
http://www.nhlbi.nih.gov/health/health-topics/topics/asthma/treatment.html
http://www.mayoclinic.com/health/asthma/DS00021