Asthma continues to be one of the most common reasons for emergency department visits and a leading cause of hospitalization. Acute management involves severity-based treatment of bronchoconstriction and underlying airway inflammation. Optimal treatment has been defined and standardized through randomized controlled trials, systematic reviews, and consensus guidelines. Implementation of clinical practice guidelines may improve clinical, quality, and safety outcomes. Asthma morbidity is disproportionately high in poor, urban, and minority children. Children treated in emergency departments commonly have persistent chronic severity, significant morbidity, and infrequent follow-up and primary asthma care, and prescription of inhaled corticosteroids is appropriate.
Key points
- •
Acute asthma management involves prompt recognition of severity and treatment using short-acting β-agonists (SABAs), anticholinergics, and systemic corticosteroids (SCSs).
- •
Children with severe exacerbations should receive high-dose SABAs mixed with ipratropium bromide as well as SCSs.
- •
Children with less-severe exacerbations may benefit from SCSs based on chronic asthma severity reflecting significant airway inflammation.
- •
Patients not improving after multiple high-dose SABA treatments should receive adjunctive therapy, such as intravenous (IV) magnesium.
- •
Many children treated for asthma in the emergency department (ED) have significant morbidity and infrequent primary asthma care; prescription of inhaled corticosteroids (ICSs) is appropriate.
Introduction
Management of acute asthma exacerbations has evolved over recent decades, with an expanding body of research driving advances in therapeutics. Asthma is a heterogeneous chronic inflammatory condition with variable phenotype, influenced by genetic and environmental determinants. Although differences in response to therapy may occur, standard treatment has been defined in the National Asthma Education and Prevention Program (NAEPP) guidelines and involves inhaled bronchodilators and SCSs. Prompt recognition of severity and initiation of therapy are important goals.
Despite advances in chronic and acute care, asthma remains a major public health issue. It is important to appreciate its epidemiology, including the significant disease burden and health disparities according to race and socioeconomic status. There are aspects of chronic care beyond the ED visit, including prescription of controller therapy and access to primary asthma care, that are also important considerations.
This article discusses current recommendations and evidence for acute asthma management.
Introduction
Management of acute asthma exacerbations has evolved over recent decades, with an expanding body of research driving advances in therapeutics. Asthma is a heterogeneous chronic inflammatory condition with variable phenotype, influenced by genetic and environmental determinants. Although differences in response to therapy may occur, standard treatment has been defined in the National Asthma Education and Prevention Program (NAEPP) guidelines and involves inhaled bronchodilators and SCSs. Prompt recognition of severity and initiation of therapy are important goals.
Despite advances in chronic and acute care, asthma remains a major public health issue. It is important to appreciate its epidemiology, including the significant disease burden and health disparities according to race and socioeconomic status. There are aspects of chronic care beyond the ED visit, including prescription of controller therapy and access to primary asthma care, that are also important considerations.
This article discusses current recommendations and evidence for acute asthma management.
Epidemiology
According to recent United States statistics, lifetime prevalence of asthma is estimated at 13% of all children, with 6.7 million experiencing active disease. More than 3.5 million children have greater than or equal to 1 exacerbation per year, resulting in approximately 600,000 ED visits. Children younger than 4 years have the highest rates of ED visits, ambulatory visits, and hospitalizations.
Asthma is uncommonly diagnosed before 12 months of age, and some clinicians hesitate to diagnose asthma in children younger than 24 months, when the diagnosis relies on history and symptoms and overlaps with transient viral bronchiolitis. A diagnosis of asthma is appropriate, however, if a child has compatible history of recurrent episodes of cough, respiratory distress, and wheezing, suggesting the characteristic features of airway obstruction, bronchial hyper-responsiveness, and airway inflammation.
Asthma disproportionately affects minority children, those in urban areas, and those of lower socioeconomic status. Puerto Rican children in the United States have the highest prevalence, at 19.2%. Black children have the highest rates of both ED visits and death, however. Moreover, with regard to preventative care, minority children have fewer ambulatory visits compared with white children and lower rates of controller medication use.
Differential diagnosis
Asthma is characterized clinically by a pattern of periodic episodes of cough, wheeze, respiratory distress, and reversible bronchospasm. Although wheezing is the most obvious symptom, asthma may also present as cough without significant wheeze. Asking a family about typical symptoms for a child can provide clarification. Pulmonary function testing can identify airway obstruction in children able to complete it (usually children older than 5 years), although often a clinical diagnosis is made.
Considering the symptoms common for asthma are nonspecific, an appropriate differential diagnoses list should be considered ( Box 1 ). A diagnosis of asthma during the first episode of wheezing can be challenging, and clinical presentation overlaps with bronchiolitis in young children.
Upper respiratory tract infection with wheezing
Bronchiolitis
Pneumonia
Pneumothorax
Congenital cardiac abnormality with heart failure
Congenital pulmonary abnormality
Foreign body
Cystic fibrosis
α 1 -Antitrypsin deficiency
Gastroesophageal reflux disease
Tracheoesophageal fistula
Allergic reaction/anaphylaxis
Vocal cord dysfunction
Toxic exposure
Severity assessment
Rapid determination of severity is important to direct appropriate therapy. Severity is a spectrum—mild, moderate, severe, and impending respiratory failure Table 1 .
| Mild | Moderate | Severe | Respiratory Arrest Imminent | |
|---|---|---|---|---|
| Key examination elements (pediatric asthma severity score) | ||||
| Wheezing | None or mild (0) None or end of expiration only | Moderate (1) Throughout expiration | Severe (2) Inspiratory/expiratory or absent due to poor air exchange | Diminished due to poor air exchange |
| Work of breathing | None or mild (0) Normal or minimal retractions | Moderate (1) Intercostal retractions | Severe (2) Suprasternal retractions, abdominal breathing | Tiring, inability to maintain work of breathing |
| Prolonged expiration | None or mild (0) Normal or minimally prolonged | Moderate (1) | Severe (2) | Severely prolonged |
| Other examination elements | ||||
| Breath Sounds/aeration | Normal | Decreased at bases | Widespread decrease | Absent/minimal |
| Symptoms | ||||
| Breathlessness | With activity or agitation | While at rest For infants: soft or shorter cry, difficulty feeding, prefers sitting | While at rest For infants: stops feeding, sits upright | |
| Talks in | Sentences | Phrases | Words | |
| Alertness | Alert | May be agitated | Agitated | Drowsy, confused |
| Measurements | ||||
| Pulse oximetry | >94% | Variable | Variable | Variable |
| PEF (% of predicted by height) | ≥70% | 40%–69% | <40% | |
Clinical scores using predominantly subjective measures, such as the pediatric asthma severity score (see Table 1 ), modified pulmonary index, and pulmonary score, have been shown valid and reliable. The NAEPP guidelines recommend objectively measuring airway obstruction using spirometry or peak expiratory flow rate (PEFR), although this may be impossible in young or severely ill children. In assessing severity and formulating treatment plans, patient history and response to medications already used for that exacerbation should be considered.
Initial standard therapy
The main goals of acute asthma treatment are 2-fold—to rapidly reverse bronchospasm and to treat underlying airway inflammation. Severity-based treatment should be initiated as soon as possible.
Short-acting β-Agonist
Albuterol or levalbuterol
Inhaled SABAs cause bronchodilation of airway smooth muscle through activation of β 2 -adrenergic receptors ( Table 2 ). Albuterol is the most commonly used SABA, a racemic mixture of 2 enantiomers—(R)-albuterol (binds β 2 -receptor and causes bronchodilation plus adverse effects of tachycardia and tremor) and (S)-albuterol (thought to have detrimental effect on airway function). Levalbuterol is a purified form of the (R)-enantiomer, marketed as an alternative with fewer adverse effects than racemic albuterol. Studies comparing racemic albuterol and levalbuterol have not consistently reported superiority over racemic albuterol, however, in improved pulmonary function or clinical outcomes, raising questions about cost effectiveness. The updated NAEPP guidelines list levalbuterol as an option for SABA treatment at half the dose of (racemic) albuterol.
| Mild | Moderate | Severe | ||
|---|---|---|---|---|
| Albuterol | ||||
| Delivery device | MDI with valved holding chamber | MDI with valved holding chamber or nebulizer | Nebulizer | |
| Frequency | Intermittent treatment every 20 min up to 3 doses in 60 min | Intermittent or continuous treatment | ||
| Dosing | Weight (kg) | MDI | Nebulizer (intermittent) | Nebulizer (continuous) |
| <5 | 2 Puffs | 1.25 mg | 5 mg/h | |
| 5–10 | 4 Puffs | 2.5 mg | 10 mg/h | |
| 10–20 | 6 Puffs | 3.75 mg | 15 mg/h | |
| >20 | 8 Puffs | 5 mg | 20 mg/h | |
| Ipratropium bromide | (Mix with albuterol) | |||
| Comment | Not proved effective | Likely effective when added to β-agonist | Effective, particularly multiple doses | |
| Delivery device | Weight (kg) | Nebulizer | ||
| Dosing | ||||
| <10 | 250 μg × 3 doses | |||
| >10 | 500 μg × 2 doses | |||
| Systemic corticosteroids | ||||
| Comment | Consider if incomplete response to initial therapy | Administer as early as possible for maximal benefit | ||
| Route | Oral | Oral route as effective as parenteral | ||
| Dose | Prednisone or prednisolone 2 mg/kg (max 60 mg) | Prednisone or prednisolone or methylprednisolone 2 mg/kg (max 60 mg) | ||
Delivery device
Albuterol can be administered using metered dose inhalers (MDIs) that have either valved holding chambers (spacer) or nebulizers; use of each requires proper technique. Although there are potential differences in lung deposition between devices, in general, studies of clinical outcomes have found equivalency or favor MDI with spacer due to shorter ED length of stay (LOS) and less tachycardia. Although nebulizers have traditionally been the preferred devices, MDI with spacer may be considered an option for children with mild and moderate exacerbations (see Table 2 ).
Data on MDI with spacer use for severe asthma are limited. Patients with severe exacerbations have significant lower airway obstruction, which limits drug deposition in the lung, and higher overall doses using nebulizer are often necessary.
Continuous nebulized SABA treatment
Continuous nebulized albuterol treatment is recommended for patients with severe exacerbations or poor response to intermittent or back-to-back dosing (see Table 2 ). A systematic review found that continuous albuterol was associated with greater PEFR improvement and lower hospitalization rate, most pronounced for those with moderate or severe exacerbations. In that review, continuous albuterol was not associated with more adverse effects (palpitations, tremors, nausea and vomiting, and potassium level when tested). Continuous nebulized levalbuterol has not been found superior to continuous albuterol.
Ipratropium Bromide
Ipratropium bromide causes bronchodilation by blocking muscarinic cholinergic receptors (see Table 2 ). It is associated with lower admission rate for children with severe exacerbations and may reduce ED LOS. Multidose protocols are associated with greater forced expiratory volume in the first second of expiration improvement and lower hospitalization rates compared with single-dose protocols.
Corticosteroids
Corticosteroids block formation of potent inflammatory mediators and reduce airway inflammation. SCSs are proved effective for moderate and severe exacerbations and should be administered as early as possible for maximum benefit (see Table 2 ). One systematic review found the reduction in hospitalization rate was most significant after 2 hours, which may be an important consideration when assessing response to therapy. Another review found that SCSs reduced relapse visits, a major ED quality outcome. Adverse events were similar between study groups in these reviews. Patients with mild exacerbations should receive SCSs if they have incomplete response to inhaled SABA.
For many ED patients, the potential benefits of SCSs outweigh the potential harms, including patients who have recently completed an SCS course but have recurrence of symptoms. Although SCS courses have been reported to be associated with alteration in bone metabolism and bone mineral density, they were not associated with increased fracture rates. Patients requiring more than 1 course of SCS in 6 months should be prescribed ICSs.
Route, dosing, duration
Oral administration of SCSs is the preferred route because of similar bioavailability compared with the parenteral route and less pain (see Table 2 ). Patients with severe exacerbations or significant vomiting may require parenteral administration. Intramuscular (IM) dexamethasone is an option. Studies report similar outcomes with IM dexamethasone compared with oral prednisone. The current recommended dose of oral prednisone or prednisolone is 1 mg to 2 mg per kg (maximum 60 mg) per day for 3 to 10 days (NAEPP). In a recent study, a 3-day course of prednisone had similar outcomes compared with a 5-day course.
One or 2 days of oral dexamethasone is reported to have similar ED relapse rates and less vomiting compared with multiple days of prednisolone and may be considered an option, although current studies are limited due to differences in protocols and variable dexamethasone and prednisolone dosing.
Inhaled corticosteroid
ICSs are beneficial for long-term asthma control, and administration during acute exacerbations may also be effective but research has some limitations. Systematic reviews have found single-dose ICS protocols similar to SCSs for some outcomes, whereas multidose protocols were associated with greater early (within 60 minutes) PEFR improvement and reduction in hospitalization rate, although these studies had significant heterogeneity. At this point, results of studies do not support replacing SCSs with ICSs in ED management of acute exacerbations.
Studies have also not found ICSs superior to SCSs for immediate post-ED outcomes. Considering the beneficial effects in chronic asthma, however, initiation or continuation of ICSs along with a short course of OCS at time of discharge should be considered.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
