Asthma

Introduction

Imagine a huge weight on your chest that you cannot remove. The weight makes it hard to breathe. Every breath becomes more difficult, and exhaling becomes next to impossible. For thousands of people who have asthma, this nightmare is a reality.

What is it?

Asthma is a chronic lung disease. Although everyone's airways react to irritants, the overly sensitive airways of the asthma patient exhibit an exaggerated response. This exaggerated response ultimately leads to inflammation, irritation, and swelling of the airways that causes limited airflow. The result is periodic attacks of coughing, wheezing (high pitched, whistle-like breathing noises that signify tight airways), and other breathing difficulties. Asthma can range from a mildly bothersome annoyance to a life-threatening medical emergency.

More on what is Asthma

Asthma can occur at any age, and often occurs in families, but it is not contagious. Asthma affects persons from diverse cultural, racial and economic backgrounds.

The effects of asthma can vary from person to person and over time. It can be intermittent or mildly persistent in some patients, and moderately persistent or severe in others. Some children suffer from moderate asthma that becomes much milder when they grow into adulthood. Other people only suffer from asthma at a certain time of the year. For some, asthma causes mild symptoms once in a while. For others, every day can be a struggle to breathe. Some asthma attacks last only a few minutes; others continue for days. Some asthma attacks are just an inconvenience. Others quickly become life threatening.

Doctors do not completely understand the mechanisms of asthma. They do not know the exact cause, nor can they explain why one person gets asthma and another doesn't. At the present time, there is no cure for asthma. However, physicians are learning more and more about the changes that occur inside the airways in an asthma attack, and they have developed effective strategies to relieve the symptoms and to limit the inflammation that is the underlying cause of an asthma episode. A patient working in partnership with his/her doctor can control his/her asthma with medication and management techniques so that it rarely progresses into a full-blown attack.

Although new strategies for controlling asthma are widely available, they do not appear to be utilized to full advantage by the nation's asthma sufferers. A recently released large scale study, called Asthma in America found that the majority of asthma sufferers in the United States do not understand that their disease is a result of chronic lung inflammation and, as a result, suffer needlessly. In fact, the survey suggests that many asthma patients underestimate the severity of their condition and take medication only when they have symptoms. Moreover in 2003, just one in nine asthma sufferers took a long-term anti-inflammatory medication that would help them avoid an asthma attack. As a result, almost half of all asthma patients -an estimated six million Americans - were hospitalized, treated in emergency rooms or required other urgent care for asthma in 2002-2003.

What causes it?

If you have asthma, your airways are overly sensitive, making you susceptible to asthma attacks when you come in contact with certain "triggers". Some of these triggers are also common to allergy sufferers. They include:

  • pet dander
  • pollen
  • mold
  • cigarette smoke
  • perfumes
  • chemicals

Other triggers for people with asthma may include:

  • exercise (known as exercise-induced asthma)
  • stress and other emotional expressions such as fear, anger and frustration
  • viral infections
  • changes in temperature or humidity
  • aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs)
  • processed foods or drinks that contain chemicals, called sulfites, as a preservative
  • certain beta-blocker drugs, including those in some eye care medications
  • gastroesophageal reflux disease, a condition in which stomach acids back up into your food pipe

Sometimes, an asthma attack occurs for no apparent reason.

Mechanism of asthma

In many ways, asthma is the result of an overreactive immune system. When the body is first exposed to a foreign substance (called an antigen) the immune system forms antibodies to fight it. The antibodys are shaped so that they fit, like a key into a particular lock, into the molecules on the surface of a particular antigen

In the case of asthma, when the lungs are exposed to an allergen, the immune system forms antibodies that attach to mast cells in the immune system. When there is later exposure to the allergen, these mast cells release inflammatory substances that are intended to protect the body from the allergen.

This causes three changes to occur in the bronchi of an asthmatic. The first change, inflammation or swelling, leads to the next two changes, constriction and sensitivity. During an asthma attack, these three airway changes get worse at the same time and this causes problems because the airways swell on the inside and narrow from the outside. This blocks the flow of air. The tightening of the airways is also called bronchospasm or bronchoconstriction. When they are in this condition, the airways are even more sensitive to animal dander, pollen, tobacco smoke, air pollution, the common cold, or cold air.
When an asthma attack occurs, the airways are constricted, reducing the amount of oxygen absorbed into the blood.

An asthma attack may appear to be mild at first, but it can become significantly more serious. Four to six hours after antigen inhalation, inflammatory cells are lured into the airways by chemicals released earlier. These inflammatory cells release chemical messengers that cause further airway obstruction through constriction, swelling and spasms of the airway. This second wave may last for days or even weeks after the first attack, and can be more severe and more dangerous than the first attack.

Who has it?

More than twenty million Americans-8.5 percent under the age of 18 -have asthma. The National Institutes of Health has identified asthma as one of the fastest growing health threats.

Currently, the direct costs of asthma exceed $14.7 billion yearly. Indirect costs (such as lost productivity in the workplace) add another $5 billion, for a total of $19.7 billion when indirect and direct costs are combined. Prescription drugs represent the largest single direct cost, at over $6 billion. Hospitalization accounts for approximately half of all direct expenditures, with 1.8 million emergency room visits in 2005.

Furthermore, it is reported that 80% of all direct medical expenditures for the treatment of asthma can be attributed to only 20% of the people with asthma. Sixty-four percent of these costs were for hospitalization. Aggressive treatment of these high-risk patients can drastically reduce the costs associated with asthma.

What are the risk factors?

While asthma itself is not hereditary, the tendency to develop it is. This means an asthmatic parent may have a child with overly sensitive airways, and exposure to certain "triggers" or irritants may cause the child to develop asthma. Asthma is more common in urban environments than in rural or suburban populations. As children, boys are usually more susceptible than girls, but in adolescence and young adulthood, asthma appears to affect both genders equally. After age 40, asthma is more common in women. Other risk factors include:

  • living in a large urban area, especially in the inner city, which may increase exposure to many environmental pollutants
  • residing in southern or western states
  • being repeatedly exposed to tobacco smoke
  • being repeatedly exposed to occupational triggers, such as chemicals used in farming and hairdressing, or in paint, steel, plastics, and electronics manufacturing
  • obesity
  • respiratory infections in childhood
  • gastroesophageal reflux disease

Serious asthma attacks are more frequent in autumn for people ages 5 to 34. Older people tend to have more asthma problems in the winter.

What are the symptoms?

Asthma symptoms, which often occur at night or early in the morning, vary with the individual and may range from mild to severe. Common symptoms include:

  • coughing
  • wheezing
  • shortness of breath
  • difficulty exhaling
  • chest tightness
  • production of phlegm

How is it treated?

There are four stages of asthma severity. Treatment is provided in a stepwise manner, dependent on the severity or stage of the disease. Many treatment strategies are based on the level of control of the condition. For example, in patients who are very poorly controlled, therapy will be increased, or ?stepped up?, in order to achieve better control. In patients who are very well controlled, therapy will be decreased, or ?stepped down?, in order to use the least amount of therapy for the most control. Below is a summary of the stages of asthma, as well as current treatment recommendations. In each case, it is important to use your short-acting beta2-agonist (fast-acting inhaler) to manage immediate symptoms of your disease.

The stages of asthma and recommended treatments are:

  • Intermittent: Considered the mildest form of asthma, with patients experiencing symptoms less than 2 days a week and 2 nights a month. Patient use of a rescue inhaler is limited to less than two days per week. These patients have no limitations in daily activities due to their condition. Treatment at this stage is limited to use of a short-acting beta2-agonist (fast acting or rescue inhaler) as needed for symptom management.

  • Mild Persistent: Patients experience asthma symptoms more than twice a week, but less than once a day, with nighttime symptoms 3-4 times per month. Use of a rescue inhaler is required no more than two days per week and not more than once per day. These patients have minor limitations in daily activities. At this stage, treatment with a low dose inhaled corticosteroid is recommended. Alternative treatments would include Cromolyn, leukotriene inhibitors, or theophylline.

  • Moderate Persistent: Patients experience symptoms more than once a day and more than one night a week, but not nightly. Use of a rescue inhaler is required almost daily. These patients have some limitation in daily activities due to their condition. At this stage, a low- to medium-dose inhaled corticosteroid and a long-acting beta2-agonist are recommended. Alternative treatments include high dose inhaled corticosteroids alone, a leukortriene inhibitor, or theophylline.

  • Severe Persistent: Considered the most severe form of asthma, with patients experiencing continuous symptoms throughout the day on most days and frequently at night, often seven nights per week. Use of a rescue inhaler is required several times per day. These patients have extremely limited activity levels due to their condition. Patients with severe persistent asthma require treatment with a high dose inhaled corticosteroid and a long-acting beta2- agonist. Alternative treatment includes an oral corticosteroid tablet or syrup that may be used to prevent or treat severe asthma symptoms. Patients with allergies and severe persistent asthma may benefit from the use of Xolair (omalizumab).

CFC's in Inhalers and Depletion of the Ozone

The production of substances that damage the earth's ozone layer is being phased out world wide under the terms of an international agreement called the Montreal Protocol on Substances that Deplete the Ozone Layer. Since most of the metered-dose inhalers (MDIs) available in the United States for the treatment of asthma contained ozone-damaging chlorofluorocarbons (CFCs), many of these MDIs are being reformulated to no longer use CFCs. Many products will be reformulated with the propellant hydrofluoroalkane (HFA), which carries medicine into the lungs with no known ozone-depleting chemicals. The reformulation effort is underway and several non-CFC products are currently approved and/or marketed for a range of different drugs (including non-CFC MDI versions for albuterol, beclomethasone, fluticasone, and ipratropium, as well as dry powder inhaler (DPI) versions of fluticasone, formoterol, and salmeterol.) Several more non-CFC products are currently being developed.

Do not be concerned that the medicines you need to treat your asthma will be removed from the market. CFC-containing MDIs will not be removed by the FDA until sufficient alternative medicines exist to serve the needs of patients. The reformulation effort should be complete by December 31, 2008, when all production and sale of MDIs that contain CFCs must stop.

If your MDI has been changed over to a non-CFC containing formulation, ask your doctor or pharmacist to educate you on the use of your new inhaler, as there may be some differences in administration technique. Additionally, as a result of the new propellant, you may experience a different taste or sensation when using your new inhaler.

Helping Yourself

In some cases, asthma can dramatically affect your life and limit your activities. However, with proper care, you may be able to overcome those limits and maintain an active lifestyle. Steroid inhalers and peak flow meters help control and monitor asthma. You can help yourself by discussing these with your doctor and learning how and when to use them.

Other things you can do to help yourself include the following:

  • Monitor and track when your asthma attacks occur, their severity and any side effects you have from medications.
  • Avoid substances that trigger your asthma.
  • Develop an action plan with your doctor for managing your condition.
  • Exercise - can help strengthen your heart and lungs so they won't have to work so hard
  • Use your air conditioner - helps reduce your exposure to airborne pollen
  • Reduce pet dander - if removing the pet from the home is not an option, you can reduce pet dander by using mattress and pillow covers, thoroughly vacuuming and cleaning carpet, avoiding pets with fur or feathers. Having pets regularly bathed or groomed also may reduce the amount of dander in your surroundings.
  • Clean regularly to minimize collection of dust
  • Decontaminate your home - encase mattresses, pillows, and box springs in dustproof covers

What is on the horizon?

With understanding comes innovation. There is continuous research underway to develop new ways to effectively treat asthma. New knowledge about asthma has led to research into new drug treatments and new uses for existing medications. These include:

  • Drug manufacturers already have realized that some people, such as children and older individuals, may not have the coordination necessary to squeeze an inhaler-type product while inhaling properly. Additional automatic delivery systems like the breath-actuated Maxair Autohaler have been introduced to make inhaled medications easier to use and provide consistent dosage.

  • Intravenous Immunoglobulin (IVIG) is being studied for treating severe asthma. IVIG may reduce the need for high doses of steroids, which can decrease side effects.

  • Several studies are investigating the effect that statins have on lung function and chronic asthma. Statins are a common class of drugs used to treat high cholesterol. However, it has been found that statins also have anti-inflammatory properties, which might make them beneficial in asthma, a disease marked by inflammation of the airways.

References

Asthma. Mayo Clinic. Diseases and Conditions. Available at URL: http://www.mayoclinic.com/health/asthma/DS00021. Accessed January 2008.

Global strategy for Asthma Mnaagement and Prevention. NIH Publication No 02-3659 Issued January, 1995 (updated 2002) Management Segment (Chapter 7): Updated 2007 from the 2006 document. The GINA reports.www.ginasthma.org. Accessed January 2008.

National Heart, Lung, and Blood Institute. Asthma: National Asthma Education and Prevention Program Expert Panel Report Guidelines for the Diagnosis and Management or Asthma - Update on Selected Topics 2002. pub no. 02.5075. June 2002.

Trends in Asthma Morbidity and Mortality 2001. Available at http://www.lungusa.org/data/asthma/asthmach_1.html. Accessed January 2008.

Barnes, P. Pathophysiology of asthma. British Journal of Clinical Pharmacology 1996;42:3-10

Busse, W, Calhoun, W, Sedgwick, J. Mechanism of airway inflammation in asthma. American Review of Respiratory Disease 1993;147(6 Pt 2):S20-24

Dolen, W. Asthma as an inflammatory disease: Implications for management (Clinical Review). The Journal of the American Board of Family Practice 1996; 9(3):182-190

Ellis, S. Managing asthma. The Express 1997;13(3):1-5

Holgate, S. Acute and chronic inflammatory mechanisms in asthma. British Journal of Clinical Practice Symposium Suppl 1995;81:11-13

Horwitz, R, Busse, W. Inflammation and asthma. Clinics In Chest Medicine 1995; 16(4): 583-599

Motheral BR, Roe CM. "Asthma: Where Have All the Guidelines Gone?", presented at the 1997 Express Scripts Outcomes Conference

National Heart Lung and Blood Institute. Expert Panel Report 2: Guidelines for the Diagnosis and Management of Asthma National Institutes of Health pub.no.97-4051. April 1997

Asthma. November 1997; http://www.njc.org/;National Jewish Medical and Research Center

Smith, D.H., Malone, D.C., Lawson, K.A., Okamot, L.J., Battista, C., Saunders, W.B. A national estimate of the economic costs of asthma. American Journal of Respiratory Critical Care Medicine 1997;156:787-793

USPDI Drug Information for the Health Care Professional. 1998;1(18)603-608

Health Care Costs and Financing: Costs associated with asthma have increased substantially since the mid-1980s. Available at http://www.ahcpr.gov/research/aug01/801RA13.htm#head2. Accessed April 2006.

Consumer Information on Why the U.S. is Eliminating the Use of Ozone-Depleting Substances Including Chlorofluorocarbons. FDA website. Available at http://www.fda.gov/cder/mdi/consumer.htm. Accessed January 2008.

Trial to Evaluate the Effect of Statins on Asthma Control in Patients with Chronic Asthma. www.clinicaltrials.gov. Accessed January 2008.

Asthma Health Condition Last Updated: March 2008

Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It is not intended to diagnose a health condition, but it can be used as a guide to help you decide if you should seek professional treatment or to help you learn more about your condition once it has been diagnosed.

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