- Review etiology and epidemiology of pediatric asthma
- Consider important history and physical exam findings in childhood asthma
- List treatment options both for chronic management and acute exacerbations
Asthma is a chronic inflammatory disease of the airways, characterized by recurrent episodes of airflow obstruction resulting from edema, bronchospasm, and increased mucus production. The degree of reversibility of airflow obstruction with bronchodilators can vary.
Patients who have asthma may experience a range of respiratory symptoms, such as wheezing, shortness of breath, cough, and chest tightness. There is a wide range in the frequency and severity of the symptoms, but uncontrolled asthma and acute exacerbations can lead to respiratory failure and death.
The exact etiology of asthma remains unclear and appears to be multifactorial. Both genetic and environmental factors seem to contribute. Positive family history is a risk factor for asthma but is neither necessary nor sufficient for the development of the disease. Multiple environmental exposures, both prenatal and during childhood, are associated with the development of asthma. 
Currently, asthma prevalence in the United States is 7.8 % (1) down from 8.4% in 2010. National surveillance data shows that prevalence varies by age, gender, race, ethnicity, geographic location, and socioeconomic status. See Table 1.
Table 1: Factors affecting Asthma Prevalence
Age Children >. Adults
Gender Overall Females> males but varied by age
(children: boys > girls and in adults: women > men)
Race African American > Caucasian
Ethnicity Hispanic > Non-Hispanic
Geographic Location Northeastern US > South or Western US
Socioeconomic status Low SES > High SES
Source: Moorman, JE et al. 2012
In a more recent pediatric study, Akinbami et al. examined trends in asthma prevalence in U.S. children ages 0 to 17 years and noted a plateau after 2009 followed in 2013 by an overall decline in pediatric asthma prevalence. However, subgroups with increasing prevalence were identified, notably in 10-17-year-olds, those living in the southern U.S. and among the poor.
Classic symptoms of asthma include cough, wheezing, chest tightness, and shortness of breath. Symptoms are often episodic and can become triggered by numerous factors, including upper respiratory tract infections, exercise, exposure to allergens, and airway irritants such as tobacco smoke. They may also be worse at night.
The physical examination should focus on three main areas, which will help to develop your differential diagnosis and identify comorbid conditions. These are the general state of nutrition and body habitus, signs of allergic disease, and signs of airway dysfunction. The physical examination may be completely normal. Features such as digital clubbing, barrel chest, localized wheezing, eczema will suggest other diagnoses or comorbid conditions.
Making the Diagnosis of Asthma
A diagnosis of asthma should be considered when any of the following key indicators are present:
History that includes recurrent episodes of cough, wheezing, difficulty breathing or chest tightness
Symptom triggers may include: Upper respiratory tract infections, exercise, exposure to furry animals, dust, mold, tobacco smoke, aerosols among others
Symptoms may disrupt sleep
In children over five years of age and adults, pre and post-bronchodilator spirometry can help confirm the diagnosis. Spirometry is a non-invasive, objective test that can be performed in the office setting and is recommended in the EPR 3 guideline as to the preferred lung function test to assign asthma severity.
The baseline spirometry provides the following information FVC (forced vital capacity), FEV1 (forced expiratory volume at 1 sec.), FEV1/FVC, and F25 to 75 (the difference between the forced expiratory volume at 25% and 75%). Assessment of the bronchodilator response begins with the baseline spirometry followed by the administration of a short-acting bronchodilator (most commonly, albuterol 2 to 4 puffs in adults and older children). According to the ATS/ERS guidelines, reversibility is significant when there is an over 12% improvement from baseline or an increase of greater than 200 ml in FEV1. In patients who do not demonstrate a significant bronchodilator response and in whom you continue to have a clinical suspicion of asthma, a 2 to 3 week trial of an oral corticosteroid may be a consideration.
STEP Therapy for Asthma
The following discussion will highlight the step therapy proposed by EPR-3.
The preferred treatment option for intermittent asthma, as well as for quick relief of asthma symptoms and the prevention of exercise-induced bronchoconstriction is a short-acting beta-2 agonist. This is referred to as STEP 1. Albuterol and levalbuterol are examples of short-acting bronchodilators. They have a quick onset of action, within 5 to 15 minutes, and a duration of action of 4 to 6 hours. Their administration is most often by nebulizer or inhaler.
STEPS 2-6 refer to options for persistent asthma. In each of these steps, inhaled corticosteroids are a component of the preferred treatment regimen.
The preferred treatment for step 2 is a low-dose inhaled corticosteroid (ICS). Montelukast can be an alternative. Montelukast is a leukotriene receptor antagonist available in 4 mg granules, or 4 mg and 5 mg chewable tablets, as well as in a 10 mg tablet formulation. Single evening dosing prescribing is by age and FDA approved for asthma control from 12 months of age.
The preferred option for step 3 is a medium dose ICS in the 0 to 4-year-old children. In the 5 to 11 year age group, the preferred option is either a medium-dose ICS or a combination ICS + long-acting beta-agonist (LABA) or leukotriene receptor antagonist (LTRA). For those ages 12 years through adulthood, the preferred choice is a low dose of ICS + LABA or medium-dose ICS. There was a black-box warning on LABAs due to concerns about increasing deaths in patients taking LABAs; however, according to more recent studies, LABAs demonstrated safety when combined with inhaled corticosteroids. LABA monotherapy is indeed associated with an increase in asthma-related mortality and serious adverse events.
Step 4 in the 0 to 4-year-old age range is a medium dose ICS + either a LABA or montelukast. In ages, 5 to 11 years and 12 and above, a medium dose ICS + LABA is the preferred option.
Step 5 for 0-4 years is high dose ICS + either LABA or montelukast; in 5-11 years and 12 and above, a high dose ICS + LABA. EPR-3 also recommends consideration of omalizumab for ages 12 and above. Since the publication of these guidelines, Omalizumab has received FDA approval for ages 6 years and above. Omalizumab is a monoclonal antibody indicated for moderate to severe persistent asthma with objective evidence of perennial aeroallergen sensitivity and inadequate control with ICS.
Step 6 for ages 0-4 years is a high dose ICS + either LABA or montelukast or oral corticosteroids; for ages 5-11 years – high dose ICS + LABA + oral systemic corticosteroid; and for ages 12 and up, high dose ICS + LABA + oral corticosteroid are preferred. Omalizumab may be a consideration for appropriate patients with allergy.
Theophylline is a medication that may be an alternative medication in Steps 2 through 6. However, its use requires caution due to its narrow therapeutic range and potential side effects, including diuresis, tremors, and headaches.
Asthma action plans are recommended for all patients with asthma. These are individualized to and developed in partnership with each patient. They include detailed directions on how to manage asthma with instructions for when the patient is well, beginning to feel symptoms, and in an acute exacerbation that necessitates medical evaluation.
EPR 3 provides guidance for referrals to an asthma specialist. While their recommendations are based on step therapy in different age groups, e.g. step 3 for ages 0 to 4 years and step 4 for those 5 years and older with the flexibility to request a consultation for step 2 in 0 to 4 years and step 3 in ages 5 and older, I find the following listing very helpful. Referrals to an asthma specialist should merit consideration whenever the diagnosis is in question, for specialized testing (e.g., PFTs, allergen skin testing, etc.) or specialized treatment is needed (e.g., allergy shots, anti-IgE medication, etc.), when asthma symptoms are not well controlled and when additional education is necessary.
Management of Acute Exacerbations
Initial management of a child who presents to the emergency department with an acute asthma exacerbation includes bronchodilators and steroids.
2.5 - 5 mg of nebulized albuterol should be given as initial management and can be re-dosed every 20 minutes. If the child is 5 years or older, 5 mg is the recommended dose. If a child is experiencing significant respiratory distress and is declining between doses, it may be re-dosed more frequently, or continuous nebulization of albuterol may be required.
Dosing of 250 to 500 mcg of ipratropium should be co-administered with albuterol for three doses in moderate to severe exacerbations.
Oral and IV steroids have been demonstrated to have equivalent potency in treating acute asthma exacerbations. Patients should be given prednisolone PO or methylprednisolone IV 1 to 2 mg/kg/day or dexamethasone 0.6 mg/kg PO or IV depending on their level of respiratory distress and ability to swallow. Dexamethasone has been shown non-inferior to a short course of prednisone or prednisolone for an acute exacerbation.
Supplemental oxygen can be applied to maintain oxygen saturation above 90 to 92%, and heliox can be considered to aid in delivering oxygen to lower airways. If patients have been treated with all of the above and still are experiencing respiratory distress, non-invasive positive pressure ventilation should be started as it may alleviate muscle fatigue and assist in maximizing inspiration.
Patients who are not improving with nebulized treatments or are becoming more somnolent warrant escalation of care.
Older children with asthma should be warned against smoking and exposure to environments that trigger attacks.
All children with asthma should have an asthma action plan updated at every office visit and revisited at any emergent or unscheduled visit. 
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