A college student presents to the student clinic with complaints of a cold, an increasingly “tight chest” and wheezing for three days. The student does not smoke, does not have any chronic illnesses and has no history of asthma, pneumonia, allergies or recent exposures to infectious illnesses. He has a brother with asthma, however, and a couple of his friends smoke. (Second-hand smoke triggers a cough and makes his chest feel tighter.) Could this be a new or undiagnosed case of asthma, and if so, which elements of this case point to a possible diagnosis of asthma?

An estimated 20 million Americans have been diagnosed with asthma.¹ Current asthma prevalence is higher among females (8.9%) than males (6.5%).² In relation to ethnic groups, asthma prevalence is highest among blacks (10.2%), followed by whites (7.6%), and Hispanics (6.8%) including Puerto Ricans (14.1%) and Mexican-Americans (5.8%).²

In 2007, the National Heart, Lung, and Blood Institute released the Expert Panel Report-3: Guidelines for the Diagnosis and Treatment of Asthma.¹ The ERP-3 guidelines, the third revision of the national asthma guidelines, have been an important practice guideline for clinicians and a valuable resource for patients with asthma and their families. The guidelines emphasize the importance of evaluating the degree of impairment due to asthma symptoms, the risk of exacerbation, the risk of decline in pulmonary function, and adverse reactions to drug treatment. The guidelines also highlight the importance of the accurate assessment of the severity of disease and the control of symptoms through careful monitoring and timely adjustment of therapy. The newest guidelines provide a simplified severity classification system, modifications to the stepwise treatment guidelines, and a renewed recommendation for patient education; reinforce the importance of a clinician-patient partnership; and recommend environmental control measures if indicated. Given the high prevalence of asthma in adults, all healthcare practitioners must to be up-to-date on the current guidelines for the diagnosis and treatment of this chronic illness. This module will summarize the key guideline changes with a focus on adults. However, the guidelines also include critical information about asthma in children.

Asthma is marked by variable and recurring symptoms, airflow obstruction, bronchial hyperresponsiveness and underlying inflammation.¹ Inflammation of the airways and airway hyperresponsiveness are the hallmark pathophysiological features of asthma, resulting in the typical symptoms: cough, wheezing, chest tightness and breathlessness. The goal of asthma pharmacotherapy is to relieve or minimize symptoms by targeting the underlying pathophysiological processes.¹

The mechanism of airflow obstruction in asthma has three components: bronchoconstriction, airway hyperresponsiveness and airway edema.1 When presented with a stimulus (such as an allergen or infection), the smooth muscle that wraps around the bronchi contracts, resulting in a narrowed air passageway. The bronchi, also referred to as airways, become hyperresponsive, meaning that they exhibit an exaggerated response to a stimulus. When disease becomes more persistent and inflammation has occurred, the airway becomes swollen and contributes to an overproduction of mucus, which may result in the formation of mucus plugs. The combination of airway edema and excess mucus further contributes to a narrowing of the air passages. Over time, a “remodeling” of the airways can occur. Remodeling changes may include fibrinous changes, injury to epithelial cells, mucus hypersecretion, the growth of new blood vessels and hypertrophy of smooth muscle. In some cases, the changes associated with airway remodeling result in nonreversible airway obstruction.

The Diagnosis

Clinicians must consider both subjective and objective data when making a diagnosis of asthma. The following subjective data are important indicators of a possible asthma diagnosis:¹

• Wheezing, described as a high-pitched whistling sound during breathing. However, the absence of wheezing does not rule out asthma.
• A history of any of the following symptoms:
  • Cough, particularly if it worsens at night
  • Recurrent symptoms of wheezing, difficulty breathing, or chest tightness
• Symptoms occur or worsen with:
  • Exercise
  • Viral infection
  • Exposure to inhalant allergens
  • Airway irritant exposures
  • Changes in weather
  • Strong emotions (such as laughing or hard crying)
  • Stress
  • Menstrual cycles
• Symptoms that occur or worsen at night, prompting the person to awaken

While the above symptoms are associated with asthma, clinicians also consider the patient history, physical examination and spirometry. In the detailed medical history, the clinician should ask about the symptoms listed above; family history (particularly for a history of asthma, respiratory disease, allergies, eczema or nasal polyps); and personal/social history (including smoking history or secondhand exposures, home setting, education, and occupation). In addition, a history of past exacerbations and treatment should be elicited. The clinician should also explore the patient’s and family’s perception of asthma and the influence it has on the patient’s life, as these elements may have a strong impact on the success of the treatment plan.

The physical examination focuses on upper airways (including the nose, sinuses, oropharynx); the chest/lungs; and the skin (to look for signs of eczema, which often coexists with asthma).¹ On auscultation, wheezes may be present depending upon the degree of obstruction at the time of the examination. In cases of severe airway obstruction, breath sounds may be very distant or absent because of severely compromised airflow.¹

Given that asthma is a disorder of airflow obstruction, spirometric measurements that document expiratory airflow limitation help in establishing the diagnosis. Two spirometric values that provide information about respiratory airflow are the forced vital capacity (FVC) and the forced expiratory volume, one second (FEV-1). During spirometry, patients first inhale to their maximal volume. At the moment of maximal inhalation volume, patients forcibly exhale as much air as they can as quickly as they can into the spirometer mouthpiece. The total amount of air expelled is the FVC. When airways are functioning normally, the patient can generally expel 80% of the FVC in one second.³ When expiratory airflow is reduced, such as in asthma, the rate of expiratory flow is reduced. Airflow obstruction is spirometrically evident if the FEV-1 value generated is less than 80% of the predicted value, which is based on established nomograms that take into consideration age, sex and height.⁴ In addition, the ratio of the FEV-1 to the FVC (called the FEV-1/FVC ratio) is reduced when expiratory airflow is impaired. For adults aged 20 to 39, the normal FEV-1/FVC ratio is 80%. It falls to 75% for the 40- to 59-year-old and to 70% for the 60- to 80-year-old.¹ Both the FEV-1 and the FEV-1/FVC ratio are used to classify the severity of asthma.¹

If airway obstruction has been established by a lower than predicted FEV-1 value, the next step is to determine whether the obstruction is at least partially reversible. To do this, the patient inhales a short-acting beta agonist (SABA) bronchodilator (such as albuterol [Proventil]) and repeats the spirometry. If the FEV-1 value improves (increases) after the SABA inhalation by at least 12% or 200 ml, the airway obstruction is considered reversible and therefore consistent with asthma. Because spirometry is effort-dependent, it is usually not possible to perform on children younger than 5.1 In addition, obstruction is evident if the ratio of the FEV-1 to the FVC is less than 70%.¹

Severity Classifications

New guidelines have revised the asthma severity classification system. There are two major categories, intermittent and persistent. The persistent classification has three subcategories: mild, moderate and severe. The severity classifications take into account indicators of impairment: the frequency of symptoms, nocturnal awakenings, SABA use, interference with normal activities, objective lung function measures (spirometry) and the frequency of exacerbations. In brief, intermittent severity is characterized by symptoms two days per week or less, nighttime awakenings two times per month or less, SABA use for symptoms two times per week or less, no interference with normal activities, normal spirometry between exacerbations, and zero to one exacerbation per year. In contrast, the severe persistent patient experiences symptoms throughout the day, has nighttime awakenings seven days per week, uses the SABA several times per day, experiences a severe limitation in daily activities, has a spirometry that shows significant obstruction (FEV-1 less than 60% predicted or personal best and/or the FEV-1/FVC ratio reduced 5% or more), and has two or more exacerbations per year.1 A complete description of the guidelines classification schema is available at http://www.nhlbi.nih.gov/guidelines/asthma/asthsumm.htm.

Asthma Control Classifications

New with this revision, the guidelines also classify asthma control and make recommendations for treatment for each level of control. Asthma is classified as “well-controlled,” “not well-controlled” or “very poorly controlled” using a schema involving reducing impairment and risk. Impairment is determined by frequency of symptoms, nocturnal awakenings, interference with normal activities, SABA use, spirometry and the patient’s responses on a quality-of-life questionnaire, such as the Asthma Therapy Assessment Questionnaire.^1,4 Risk is assessed by the frequency of exacerbations, decline in lung function, and treatment-related adverse effects.¹ In terms of impairment, well-controlled patients have symptoms two or fewer days per week, experience nocturnal awakenings two times or less per month, use SABA two times or less per week, do not have any interference with normal activities, have normal lung function (FEV-1 more than 80% of predicted value), and score favorably on the quality-of-life questionnaire. In terms of risk, the patient who is well controlled has one or no exacerbations per year. In contrast, impairment of a very poorly controlled patient is characterized by symptoms throughout the day, nighttime awakenings four or more times per week, extreme limitations in daily activities, the use of SABA several times per day, impaired spirometry (FEV-1 less than 60% of predicted or personal best), and a low score on quality-of-life questionnaires. In terms of risk, a poorly controlled patient has two or more exacerbations per year.¹ A complete description of the schema for assessing asthma control, including a description for the not well-controlled patient, is at http://www.nhlbi.nih.gov/guidelines/asthma/asthsumm.htm.

Step by Step

The main goals of asthma treatment are to reduce impairment and minimize risks through the following mechanisms:¹

• Reduce impairment:
  • Prevent chronic and troublesome symptoms, such as cough and breathlessness during the day or night or after exercise/exertion.
  • Use an inhaled short-acting bronchodilator for quick relief of symptoms two days or less per week.
  • Maintain normal or near-normal pulmonary function.
  • Maintain normal activities including exercise and attendance at work or school.
  • Meet the patient and family expectations for care.
• Reduce risk:
  • Prevent recurrent exacerbations and minimize emergency care visits or hospitalizations.
  • Prevent loss of lung function.
  • Provide optimal pharmacotherapy while eliminating or minimizing adverse effects.

Medications

Asthma medications are broadly classified into two categories: long-term control medications and quick-relief medications. Quick-relief medications include SABA, anti-cholinergic agents, and systemic corticosteroids. Long-term medications include long-acting beta2-agonist bronchodilators (LABA), mast cell stabilizers (such as cromolyn sodium [Intal] and nedocromil [Tilade]), immunomodulators, leukotriene modifiers, methylxanthines (such as theophylline [Theodur]), and corticosteroids, including both systemic and inhaled forms. For an overview of long-term controller and quick-relief asthma medications, see the sidebars “Usual Doses for Long-Term Control Medications Ages 12 Through Adult” and “Usual Doses for Quick-Relief Medications Ages 12 Through Adult.”

Inhaled asthma medications are delivered in a variety of devices. These include metered dose inhalers (MDIs), breath-actuated inhalers, dry powder inhalers (DPIs), nebulizer machines and spacer devices. See the sidebar “Aerosol Delivery Devices” for more information. Healthcare practitioners should be familiar with the use of these devices and be prepared to instruct the patient on their use and care.

Environmental Control

The guidelines emphasize the importance of identifying and managing triggers, especially environmental triggers, such as dust mites, aeroallergens and pet dander. While these may not be triggers for all people with asthma, many patients benefit from environmental measures to control them. For example, removing curtains and carpets from the bedroom of a person who is allergic to dust mites may reduce exposures. More information about environmental control measures and patient education handouts can be found at www.nhlbi.nih.gov/guidelines/asthma/asthsumm.htm.

When asthma is first diagnosed or is not responding to treatment as expected, the clinician should consider comorbidities that may be triggering or contributing to asthma. Examples include gastroesophageal reflux, allergic rhinitis, obstructive sleep apnea, obesity, stress, depression and allergic bronchopulmonary aspergillosis. In many cases, when these comorbidities are recognized and properly managed, asthma can be better controlled.

A Partnership

Since their inception, the guidelines have emphasized the importance of patient education, established through a close clinician-patient partnership for care. Education should include the basic facts about asthma with an emphasis on the role of inflammation, the role of medications and the difference between long-term controllers and quick-relief medications, the proper use of medications and devices, self-monitoring of symptoms or peak flow values, the use of an action plan in response to symptom or peak flow changes, and situations in which to seek medical care. When applicable, environmental control measures should also be taught and reinforced at each follow-up visit. 

The Peak Expiratory Flow Meter

Many asthma patients use a peak expiratory flow meter to monitor their symptoms. A PEFM is a portable device that measures airflow at its maximal rate during peak expiration and that can be used for office assessment if a spirometer is not available. The predicted peak expiratory flow rate, or PEFR, varies depending on a patient’s age, sex, and height; any value 80% or better than the predicted value is considered normal. The PEFR measurement reflects airway function and provides objective evidence of the degree of airway obstruction at that moment. A lower-than-predicted value indicates airway obstruction and when considered with other factors, such as symptoms, can be useful to both the patient and clinician in guiding self-care. The meter is easy to use; patients learn how to measure peak flow in a few minutes.

The Action Plan

The guidelines emphasize self-management, which is possible by establishing symptom-based or peak flow value-based action plans.¹ A written plan is particularly important for patients with moderate to severe asthma.¹ If the plan is based on symptom changes, such as wheezing or nighttime awakenings due to chest symptoms, the patient receives instructions for managing, such as starting oral steroids or calling his or her provider. If the action plan is based on peak flow values, the written plan incorporates personalized PEFR parameters that include instructions for medication or for other actions to take. In general, if the PEFR is at least 80% of the predicted or personal best values for the patient, no changes in treatment are needed. If it is below 80% of predicted value, changes in the treatment plan are warranted. The guidelines contain patient action plan handouts to use in patient education.

Asthma is a complex disorder of the airways that results in cough, breathlessness, chest tightness, and in some cases, excess sputum. Major pathophysiological features of asthma are hyperresponsiveness, bronchospasm, airway edema and airway inflammation. The diagnosis of asthma includes a thorough history and an appropriately focused physical exam plus objective measures, such as spirometry. Once asthma has been identified, its severity must be established to determine therapies to achieve optimal function. The current asthma treatment guidelines emphasize the importance of reducing the impairment and risks associated with the disease. Asthma medications target the underlying pathophysiology of the disorder and include medications used for quick relief as well as to control the disease over the long term. Patient education and a clinician-patient partnership are keys to successful asthma management.

Gannett Education guarantees this educational activity is free from bias.