Diagnosis and management of asthma
PRIMARY CARE OR HOSPITAL MANAGEMENT OF ACUTE ASTHMA EXACERBATIONS Assessment of exacerbation severity
Conduct a brief history and examination concurrently with the initiation of therapy (Box 6-8, Box 6-9). The presence of any of the features of a severe exacerbation listed in Box 6-9 are an indication of the need for urgent treatment and immediate transfer to hospital (Evidence D). Oxygen saturation from pulse oximetry of <92% on presentation (before oxygen or bronchodilator treatment) is associated with high morbidity and likely need for hospitalization; saturation of 92–95% is also associated with higher risk.357 Agitation, drowsiness and confusion are features of cerebral hypoxemia.
A quiet chest on auscultation indicates minimal ventilation, insufficient to produce a wheeze.
Several clinical scoring systems such as PRAM (Preschool Respiratory Assessment Measure) and PASS (Pediatric Asthma Severity Score) have been developed for assessing the severity of acute asthma exacerbations in children.480
Box 6-9. Initial assessment of acute asthma exacerbations in children 5 years and younger
Symptoms Mild Severe*
Altered consciousness No Agitated, confused or drowsy
Oximetry on presentation (SaO2)** >95% <92%
Speech† Sentences Words
Pulse rate <100 beats/minute >200 beats/minute (0–3 years)
>180 beats/minute (4–5 years)
Central cyanosis Absent Likely to be present
Wheeze intensity Variable Chest may be quiet
*Any of these features indicates a severe asthma exacerbation. **Oximetry before treatment with oxygen or bronchodilator.
† The normal developmental capability of the child must be taken into account.
Indications for immediate transfer to hospital
Children with features of a severe exacerbation that fail to resolve within 1–2 hours despite repeated dosing with inhaled SABA, with or without OCS, must be referred to hospital for observation and further treatment (Evidence D). Other indications are respiratory arrest or impending arrest; lack of supervision in the home or doctor’s office; and recurrence of signs of a severe exacerbation within 48 hours (particularly if treatment with OCS has already been given). In addition, early medical attention should be sought for children less than 2 years of age as the risk of dehydration and respiratory fatigue is increased (Box 6-10).
Emergency treatment and initial pharmacotherapy Oxygen
Treat hypoxemia urgently with oxygen by face mask to achieve and maintain percutaneous oxygen saturation 94–98%
(Evidence A). To avoid hypoxemia during changes in treatment, children who are acutely distressed should be treated immediately with oxygen and SABA (2.5 mg of salbutamol or equivalent diluted in 3 mL of sterile normal saline) delivered by an oxygen-driven nebulizer (if available). This treatment should not be delayed, and may be given before the full assessment is completed.
Box 6-10. Indications for immediate transfer to hospital for children 5 years and younger
Immediate transfer to hospital is indicated if a child ≤5 years with asthma has ANY of the following:
• At initial or subsequent assessment o Child is unable to speak or drink o Cyanosis
o Subcostal retraction
o Oxygen saturation <92% when breathing room air o Silent chest on auscultation
• Lack of response to initial bronchodilator treatment
o Lack of response to 6 puffs of inhaled SABA (2 separate puffs, repeated 3 times) over 1–2 hours o Persisting tachypnea* despite three administrations of inhaled SABA, even if the child shows other clinical
signs of improvement
• Social environment that impairs delivery of acute treatment, or parent/carer unable to manage acute asthma at home
*Normal respiratory rates: <60 breaths/minute in children 0–2 months; <50 breaths/minute in children 2–12 months;
<40 breaths/minute in children 1–5 years.
Bronchodilator therapy
The initial dose of SABA may be given by a pMDI with spacer and mask or mouthpiece or an air-driven nebulizer; or, if oxygen saturation is low, by an oxygen-driven nebulizer (as described above). For most children, pMDI plus spacer is favored as it is more efficient than a nebulizer for bronchodilator delivery470,481 (Evidence A). The initial dose of SABA is two puffs of salbutamol (100 mcg per puff) or equivalent, except in acute, severe asthma when six puffs should be given.
When a nebulizer is used, a dose of 2.5 mg salbutamol solution is recommended. The frequency of dosing depends on the response observed over 1–2 hours (see below).
For children with moderate-severe exacerbations and a poor response to initial SABA, ipratropium bromide may be added, as 2 puffs of 80mcg (or 250mcg by nebulizer) every 20 minutes for 1 hour only.380
Magnesium sulfate
The role of magnesium sulfate is not yet established for children 5 years and younger, because there are few studies in this age group. Nebulized isotonic magnesium sulfate may be considered as an adjuvant to standard treatment with nebulized salbutamol and ipratropium in the first hour of treatment for children ≥2 years old with acute severe asthma (e.g. oxygen saturation <92%, Box 6-9, p.115), particularly those with symptoms lasting <6 hours.482 Intravenous magnesium sulfate in a single dose of 40-50 mg/kg (maximum 2 g) by slow infusion (20–60 minutes) has also been used.
Assessment of response and additional bronchodilator treatment
Children with a severe asthma exacerbation must be observed for at least 1 hour after initiation of treatment, at which time further treatment can be planned.
• If symptoms persist after initial bronchodilator: a further 2–6 puffs of salbutamol (depending on severity) may be given 20 minutes after the first dose and repeated at 20-minute intervals for an hour. Failure to respond at 1 hour, or earlier deterioration, should prompt urgent admission to hospital and a short-course of oral corticosteroids (Evidence D).
• If symptoms have improved by 1 hour but recur within 3–4 hours: the child may be given more frequent doses of bronchodilator (2–3 puffs each hour), and oral corticosteroids should be given. The child may need to remain in the emergency room, or, if at home, should be observed by the family/carer and have ready access to emergency care. Children who fail to respond to 10 puffs of inhaled SABA within a 3–4 hour period should be referred to hospital (Evidence D).
• If symptoms resolve rapidly after initial bronchodilator and do not recur for 1–2 hours: no further treatment may be required. Further SABA may be given every 3–4 hours (up to a total of 10 puffs/24 hours) and, if symptoms persist beyond 1 day, other treatments including inhaled or oral corticosteroids are indicated (Evidence D), as outlined below.
Box 6-11.Initial management of asthma exacerbations in children 5 years and younger
Therapy Dose and administration
Supplemental oxygen 24% delivered by face mask (usually 1 L/minute) to maintain oxygen saturation 94–98%
Short-acting beta2 -agonist (SABA)
2–6 puffs of salbutamol by spacer, or 2.5 mg of salbutamol by nebulizer, every 20 minutes for first hour*, then reassess severity. If symptoms persist or recur, give an additional 2–3 puffs per hour. Admit to hospital if >10 puffs required in 3–4 hours.
Systemic corticosteroids
Give initial dose of oral prednisolone (1–2 mg/kg up to a maximum 20 mg for children <2 years old; 30 mg for children 2–5 years)
OR, intravenous methylprednisolone 1 mg/kg 6-hourly on day 1 Additional options in the first hour of treatment
Ipratropium bromide For children with moderate-severe exacerbations, 2 puffs of ipratropium bromide 80mcg (or 250mcg by nebulizer) every 20 minutes for 1 hour only
Magnesium sulfate Consider nebulized isotonic magnesium sulfate (150mg) 3 doses in the first hour of treatment for children aged ≥2 years with severe exacerbation (Box 6-9, p.115)
*If inhalation is not possible an intravenous bolus of terbutaline 2 mcg/kg may be given over 5 minutes, followed by continuous infusion of 5 mcg/kg/hour483 (Evidence C). The child should be closely monitored, and the dose should be adjusted according to clinical improvement and side-effects. See below for additional and ongoing treatment, including controller therapy.
Additional treatment
When treatment in addition to SABA is required for an exacerbation, the options available for children in this age group include ICS; a short course of oral corticosteroid; and/or LTRA (see p.113). However, the clinical benefit of these interventions – particularly on endpoints such as hospitalizations and longer-term outcomes – has not been impressive.
Maintain current controller treatment (if prescribed)
Children who have been prescribed maintenance therapy with ICS, LTRA or both should continue to take the prescribed dose during and after an exacerbation (Evidence D).
Inhaled corticosteroids
For children not previously on ICS, an initial dose of ICS twice the low daily dose indicated in Box 6-6 (p.110) may be given and continued for a few weeks or months (Evidence D). Some studies have used high dose ICS (1600 mcg/day, preferably divided into four doses over the day and given for 5–10 days) as this may reduce the need for
OCS.342,458,459,484,485
However, the potential for side-effects with high dose ICS should be taken into account, especially if used repeatedly, and the child should be monitored closely. For those children already on ICS, doubling the dose was not effective in a small study in older children,340 and there are no studies in children 5 years and younger; this approach should be reserved mainly for individual cases, and should always involve regular follow up (Evidence D).
Oral corticosteroids
For children with severe exacerbations, a dose of OCS equivalent to prednisolone 1–2 mg/kg/day, with a maximum of 20 mg/day for children under 2 years of age and 30 mg/day for children aged 2–5 years, is currently recommended (Evidence A),486 although several studies have failed to show any benefits when given earlier (e.g. by parents) during periods of worsening wheeze (Evidence D).473-476,487,488
A 3–5 day course is sufficient in most children and can be stopped abruptly (Evidence D).
Regardless of whether the intervention is corticosteroids or LTRA, the severity of symptoms must be carefully monitored. The sooner therapy is started in relation to the onset of symptoms, the more likely it is that the impending exacerbation may be clinically attenuated or prevented.
Discharge and follow up after an exacerbation
Before discharge, the condition of the child should be stable (e.g. he/she should be out of bed and able to eat and drink without problems).
Children who have recently had an asthma exacerbation are at risk of further episodes and require follow up. The purpose is to ensure complete recovery, to establish the cause of the exacerbation, and, when necessary, to establish appropriate maintenance treatment and adherence (Evidence D).
Prior to discharge from the emergency department or hospital, family/carers should receive the following advice and information (all are Evidence D).
• Instruction on recognition of signs of recurrence and worsening of asthma. The factors that precipitated the exacerbation should be identified, and strategies for future avoidance of these factors implemented.
• A written, individualized action plan, including details of accessible emergency services.
• Careful review of inhaler technique.
• Further treatment advice explaining that:
o SABAs should be used on an as-needed basis, but the daily requirement should be recorded to ensure it is being decreased over time to pre-exacerbation levels
o ICS has been initiated where appropriate (at twice the low initial dose in Box 6-6 (p.110) for the first month after discharge, then adjusted as needed) or continued, for those previously prescribed controller medication.
• A supply of SABA and, where applicable, the remainder of the course of oral corticosteroid, ICS or LTRA.
• A follow-up appointment within 2–7 days and another within 1–2 months, depending on the clinical, social and practical context of the exacerbation.
SECTION 2. CHILDREN 5 YEARS AND YOUNGER