Asthma



Asthma


Karen J. Tietze



Approximately 25.7 million people in the United States have asthma, with a prevalence of 9.5% and 7.7% in children 0 to 17 years and adults 18+ years, respectively (Moorman et al., 2012). Asthma is more common in persons below 100% of the federal poverty rate and in persons living in the northeast United States (Moorman et al., 2012). Asthma prevalence is greater in blacks than in whites (11.2% vs. 7.7%), in boys than in girls (11.1% vs. 7.8%), and in women than in men (9.7% vs. 5.7%) (Moorman et al., 2012). In 2009, asthma accounted for 10.6 million office visits, 2.1 million emergency department visits, and 479,300 hospitalizations (Moorman et al., 2012). The cost of asthma in the United States is approximately $56 billion per year (Centers for Disease Control and Prevention [CDC], 2013b). The noneconomic costs of asthma are high. Nine persons with asthma die from asthma every day and nearly one in three adults and one in two children miss 1 day or more of work or school for asthma-related reasons (CDC, 2013b).

The current National Asthma Education and Prevention Program (NAEPP) guidelines for the diagnosis and management of asthma were released in 2007 (NAEPP, 2007). The guidelines, originally developed in 1997 by an expert panel commissioned by the NAEPP Coordinating Committee of the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH), were updated in 2002 and 2007. The 1993 Global Initiative for Asthma (GINA) Global Strategy for Asthma Management and Prevention report, an international collaboration of the NHLBI and the World Health Organization, is updated annually (GINA, 2014).


CAUSES

Asthma is a heterogeneous chronic inflammatory medical condition of unknown etiology. The hygiene hypothesis theorizes that a lack of exposure to a variety of microbiological agents at a young age creates a predominant T helper cell type-2 (Th2) lymphocyte immune response that is associated with allergy (Brown et al., 2013). Some genetic associations have been identified. For example, although there is no single “asthma gene,” more than 100 single nucleotide polymorphisms (SNPs) of the gene that encodes the ADAM metallopeptidase domain 33 gene (ADAM33) have been identified. Smooth muscle, fibroblasts, and myofibroblasts express ADAM-related proteins with a variety of signaling, adhesion, and fusion functions that influence the epithelial-mesenchymal unit (EMTU). Additionally, more than 25 polymorphic genes expressed in the EMTU have been identified.

Common asthma phenotypes include allergic asthma, nonallergic asthma, late-onset asthma, asthma with fixed airflow limitation, and asthma with obesity. Symptom triggers include upper respiratory tract viral infections, allergens, exercise, changes in the weather, laughter, exposure to inhaled irritants (e.g., smoke, vehicle exhaust fumes, strong smells), gastroesophageal reflux disease (GERD), aspirin (in individuals sensitive to aspirin), stress, and exposure to sulfites. Hormonal changes during a woman’s menstrual cycle or during pregnancy may trigger or worsen asthma symptoms.




DIAGNOSTIC CRITERIA

The diagnosis of asthma is based on the presence of symptoms consistent with asthma and the presence of variable airflow limitation. Typical asthma symptoms include wheeze, shortness of breath, cough, and chest tightness. These symptoms are not exclusive to asthma; persons with a variety of upper and lower respiratory tract (e.g., inhaled foreign body, vocal cord dysfunction, bronchopulmonary dysplasia, cystic fibrosis, chronic obstructive pulmonary disease) and cardiovascular (e.g., pulmonary emboli, heart failure) medical conditions have the same symptoms. Asthma symptoms and symptom severity are variable. Persons with asthma may be symptom free for short or prolonged periods of time. Symptom intensity varies from mild to severe; symptoms typically worsen at night or early morning, often waking the patient.








TABLE 25.1 Asthma Severity—Chronic Disease Classification (Age 12 Years and Older)


























































Intermittent


Mild Persistent


Moderate Persistent


Severe Persistent


Severity Components


Step 1


Step 2


Step 3 and Step 4


Step 5 and Step 6


Symptoms


2 or fewer days per week


More than 2 days per week but not daily


Daily


Throughout the day


Nighttime awakenings


2 or fewer nights per month


3 to 4 nights per month


More than 1 night per week but not nightly


Often 7 nights per week


Short-acting beta2-adrenergic agonist use for symptom control


2 or fewer days per week


More than 2 days per week but not more than one time per day


Daily


Several times per day


Interference with normal activity


None


Minor limitation


Some limitation


Extremely limited


Exacerbations requiring systemic corticosteroids


0-1 per year


2 or more per year


2 or more per year


2 or more per year


Lung function


Normal FEV1/FVC:


8-19 y: 85%


20-39 y: 75%


40-59 y: 75%


60-80 y: 70%


Normal FEV1 between exacerbations


FEV1 ≥ 80% predicted


FEV1/FVC normal


FEV1 ≥ 80% predicted


FEV1/FVC normal


FEV1 > 60% but < 80% predicted


FEV1/FVC reduced 5%


FEV1 < 60% predicted


FEV1/FVC reduced > 5%


Severity is determined by the most severe category for any feature.


FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf


The physical examination is nonspecific and may be normal. Wheezing may be absent or range from soft end-expiratory wheezing to loud inspiratory and expiratory wheezing; the chest may be silent during a severe exacerbation. Nasal polyps or signs of allergic rhinitis or other atopic medical conditions such as eczema may be present. Persons with a severe asthma exacerbation may present with hunched shoulders, a preference for sitting upright, cyanosis, use of accessory respiratory muscles (abdominal, sternocleidomastoid), elevated or decreased blood pressure, tachycardia or bradycardia, tachypnea or bradypnea, an inability to speak in full sentences, and anxiety.

Spirometry measures lung volumes during a forced maximal exhalation. Airflow limitation is assessed using the forced expiratory volume in the first second (FEV1), the total volume of exhaled air (forced vital capacity, FVC), and the FEV1/FVC ratio. Airflow obstruction is present when the FEV1/FVC is less than 0.70. Bronchoprovocation testing with methacholine or histamine may be performed in patients with suspected asthma who have normal baseline airflow. The current NAEPP guidelines categorize asthma severity in children older than 4 years of age and adults according to nonspirometric and spirometric criteria (Tables 25.1 and 25.2). Children 0 to 4 years of age are
classified according to nonspirometric criteria (Table 25.3). A reduced peak expiratory flow (PEF) is consistent with airway obstruction but is not diagnostic of asthma. PEF is commonly used for self-monitoring and assessment of airway obstruction reversibility following inhalation of a short-acting bronchodilator. Spirometry is performed at baseline (prior to starting treatment), after 3 to 6 months of treatment, then repeated annually or more frequently if indicated.








TABLE 25.2 Asthma Severity—Chronic Disease Classification (Children 5-11 Years of Age)



















































Severity Components


Intermittent


Mild Persistent


Moderate Persistent


Severe Persistent


Symptoms


2 or fewer days per week


More than 2 days per week but not daily


Daily


Throughout the day


Nighttime awakenings


2 or fewer nights per month


3 to 4 nights per month


More than 1 night per week but not nightly


Often 7 times per week


Short-acting beta2-adrenergic agonist use for symptom control


2 or fewer days per week


More than 2 days per week but not daily


Daily


Several times per day


Interference with normal activity


None


Minor limitation


Some limitation


Extremely limited


Exacerbations requiring systemic corticosteroids


0 to 1 per year


2 or more per year


2 or more per year


2 or more per year


Lung function


Normal FEV1 between exacerbations


FEV1 ≥ 80% predicted


FEV1/FVC > 85%


FEV1 ≥ 80% predicted


FEV1/FVC > 80%


FEV1 60%-80% predicted


FEV1/FVC = 75-80%


FEV1 < 60% predicted


FEV1/FVC < 75%


Severity is determined by the most severe category for any feature.


FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf









TABLE 25.3 Asthma Severity—Chronic Disease Classification (Children 0 to 4 Years of Age)











































Severity Components


Intermittent


Mild Persistent


Moderate Persistent


Severe Persistent


Symptoms


2 or fewer days per week


More than 2 days per week but not daily


Daily


Throughout the day


Nighttime awakenings


0


1 to 2 nights per month


3-4 nights per month


More than 1 night per week


Short-acting beta2-adrenergic agonist use for symptom control


2 or fewer days per week


More than 2 days per week but not daily


Daily


Several times per day


Interference with normal activity


None


Minor limitation


Some limitation


Extremely limited


Exacerbations requiring systemic corticosteroids


0 to 1 per year


≥2 in 6 mo or ≥4 wheezing episodes per 1 y lasting >1 day AND risk factors for persistent asthma


Severity is determined by the most severe category for any feature.


FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf


Airflow obstruction reversibility, an important parameter for the diagnosis of asthma, is documented by comparing baseline FEV1 to postbronchodilator FEV1 10 to 15 minutes following the administration of 2 to 4 puffs of a short-acting
beta-adrenergic drug. The NAEPP guidelines define airflow obstruction reversibility as an increase in FEV1 of at least 12% and an absolute increase in FEV1 of at least 200 mL (NAEPP, 2007).








TABLE 25.4 Asthma Control Assessment





















































Well Controlled


Not Well Controlled


Very Poorly Controlled


Symptoms


2 or fewer days per week


More than 2 days per week


Throughout the day


Nighttime awakenings


2 or fewer nights per month


1 to 3 nights per week


4 or more nights per week


Interference with normal activities


None


Some limitations


Extremely limited


Short-acting beta2-adrenergic agonist use for symptom control


2 or fewer days per week


More than 2 days per week


Several times per day


FEV1 or PEF


>80% predicted or personal best


60%-80% predicted or personal best


<60% predicted or personal best


Validated questionnaire


ATAQTM 0


ACTTM ≥ 20


ATAQTM 1-2


ACTTM 16-19


ATAQTM 3-4


ACTTM ≤ 15


Exacerbations


0 to 1 per year


≥2 per year


≥2 per year


Recommended action*




  • Maintain current step



  • Regular follow-up every 1-6 mo



  • Consider stepping down if well controlled for at least 3 mo




  • Step up one step



  • Reevaluate in 2-6 weeks




  • Consider short-course oral CS



  • Step up 1-2 steps



  • Reevaluate in 2 weeks


* If medication-related side effects, consider alternate treatment options.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf



INITIATING DRUG THERAPY

Drug therapy is initiated according to the age-specific NAEPP chronic disease recommendations (Tables 25.4, 25.5, 25.6). All persons with asthma, regardless of the severity of asthma, require a short-acting beta2-adrenergic agonist (SABA) bronchodilator for quick relief of acute symptoms. Long-term control medication is added according to the severity of disease. The GINA guidelines recommend reassessing 1 to 3 months after starting treatment and then every 3 to 12 months (GINA, 2015).








TABLE 25.5 Stepwise Approach for Managing Asthma (Children12 Y of Age and Adults)

























Step 1 Intermittent


Step 2 Mild Persistent


Step 3 Moderate Persistent


Step 4 Moderate Persistent


Step 5 Severe Persistent


Step 6 Severe Persistent


Preferred: SABA PRN


Preferred:


Low-dose ICS


Alternative:


Cromolyn, LTRA, or theophylline


Preferred:


Low-dose ICS + LABA


OR


Medium-dose ICS


Alternative:


Low-dose ICS + either LTRA, theophylline, or zileuton


Preferred:


Medium-dose ICS + LABA


Alternative:


Medium-dose ICS + either LTRA, theophylline, or zileuton


Preferred:


High-dose ICS + LABA


AND


Consider omalizumab for patients who have allergies


Preferred:


High-dose ICS + LABA + oral CS


AND


Consider omalizumab for patients who have allergies


Patient education and environmental control at each step


Quick-relief medication for all patients


SABA, inhaled short-acting beta2 agonist; ICS, inhaled corticosteroid; LABA, inhaled long-acting beta2 agonist; CS, corticosteroid.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf


Treatment can be stepped down to a less intensive regimen if asthma symptoms have been well controlled for 3 months. Stepping down treatment is done systematically with close monitoring of asthma control. Oral corticosteroids are reduced
and then discontinued first. The dose of inhaled corticosteroid (ICS) may then be reduced by 50%. Further reductions in therapy can be made by reducing the dose of the ICS/long-acting bronchodilator regimen to once daily. The long-term control regimen may be stopped if the person with asthma has been free of symptoms for 6 to 12 months and has no risk factors for exacerbations (GINA, 2015).








TABLE 25.6 Stepwise Approach for Managing Asthma (Children 5-11 y of Age)

























Step 1 Intermittent


Step 2 Mild Persistent


Step 3 Moderate Persistent


Step 4 Moderate Persistent


Step 5 Severe Persistent


Step 6 Severe Persistent


Preferred:SABA PRN


Preferred:


Low-dose ICS


Alternative:


Cromolyn, LTRA, or theophylline


Preferred:


EITHER:


Low-dose ICS + either LABA, LTRA, or theophylline


OR


Medium-dose ICS


Preferred:


Medium-dose ICS + LABA


Alternative:


Medium-dose ICS + either LTRA or theophylline


Preferred:


High-dose ICS + LABA


Alternative:


High-dose ICS + either LTRA or theophylline


Preferred:


High-dose ICS + LABA + oral systemic CS


Alternative:


High-dose ICS + either LTRA or theophylline + oral systemic corticosteroid


Patient education and environmental control at each step


Quick-relief medication for all patients


SABA, inhaled short-acting beta2 agonist; ICS, inhaled corticosteroid; LABA, inhaled long-acting beta2 agonist; CS, corticosteroid.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf


Treatment is stepped up if persons with asthma are not well controlled despite 2 to 3 months of treatment with long-term control medication. Medication adherence, inhaler drug delivery technique, environmental exposures, and concurrent medications must be assessed and any issues addressed before stepping up to a more intensive medication regimen. Alternate treatment should be stopped and the preferred treatment regimen tried before stepping up therapy.








TABLE 25.7 Stepwise Approach for Managing Asthma (Children 0-4 Years of Age)

























Step 1 Intermittent


Step 2 Mild Persistent


Step 3 Moderate Persistent


Step 4 Moderate Persistent


Step 5 Severe Persistent


Step 6 Severe Persistent


Preferred: SABA PRN


Preferred:


Low-dose ICS


Alternative:


Cromolyn or montelukast


Preferred:


Medium-dose ICS


Preferred:


Medium-dose ICS + either LABA or montelukast


Preferred:


High-dose ICS + either LABA or montelukast


Preferred:


High-dose ICS + either LABA or montelukast


AND


Oral systemic CS


Patient education and environmental control at each step


Quick-relief medication for all patients


SABA, inhaled short-acting beta2 agonist; ICS, inhaled corticosteroid; LABA, inhaled long-acting beta2 agonist; CS, corticosteroid.


From National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health. 2007 Expert Panel Report III: Guidelines for the diagnosis and management of asthma. Bethesda, MD: U.S. Department of Health and Human Services. Originally published July 2007. Revised 2002, August 2007. NIH Publication No. 07-4051. Retrieved from www.nhlbi.nih.gov/files/docs/guidelines/asthgdln.pdf

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Nov 11, 2018 | Posted by in PHARMACY | Comments Off on Asthma
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