Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU
Asthma is the most common chronic respiratory disease, affecting up to 10% of adults and 30% of children (90% of patients with asthma have allergic rhinitis, 30% of patients with allergic rhinitis have asthma).
Key points
Preschool wheeze should be divided into:
- “episodic viral” wheeze (EVW) - triggered by URIs
- “multiple trigger” wheeze (MTW) - triggered by URIs but also exercise, smoke and allergen exposure
These 2 phenotypes can change within an individual over time.
Wheeze Phenotypes in Preschool Children (click to enlarge the image):
Lower respiratory tract illnesses with wheeze are common, occurring in 30% of all preschool children (defined as aged between 1 and 5 years).
No treatment prevents progression of preschool wheeze to school age asthma, so treatment is driven solely by current symptoms
In all but the most severe cases, episodic symptoms should be treated with episodic treatment.
If trials of prophylactic treatment are contemplated, they should be discontinued at the end of a strictly defined time period because many respiratory symptoms remit spontaneously in preschool children.
Oral steroids (prednisolone) are not indicated in preschool children with attacks of wheeze who are well enough to remain at home and in many children, especially those with episodic viral wheeze, who are admitted to hospital.
What is wheeze?
The term wheeze is often used imprecisely. Some languages do not even have a word for wheeze. Wheeze is a high pitched whistling sounds associated with increased work of breathing. Studies have shown that physicians auscultating the chest accurately identify wheeze; parents and nurses were much less reliable.
Here is what wheezing sounds like (click to play the embedded video):
How common is wheeze in preschool children?
Preschool wheeze is very common: 26% of infants have at least one episode of wheeze by the age of 18 months.
Early aeroallergen sensitization is predictive of ongoing symptoms and loss of lung function at school age.
Is this wheeze asthma?
This question is commonly asked by parents. What most parents actually want to know is whether their child will go on with symptoms and the need for treatment into school age and beyond. Severe preschool wheeze which is multiple trigger wheeze is associated with more airflow obstruction and airway pathology (eosinophilic inflammation and remodeling) similar to childhood and adult asthma.
Does preschool wheeze lead to asthma?
Several clinical predictive indices for future risk of asthma have been developed based on:
- atopic manifestations
- indirect evidence of airway inflammation, such as peripheral blood eosinophil count
- severity of preschool wheeze
All predictive indices have a high negative predictive value and a poor positive predictive value (typically positive predictive values 44-54, negative 81-88).
Children who have only episodic viral wheeze (EVW) have no increased risk of atopy or respiratory symptoms in the long term once they reach the age of 14.
Modified Asthma Predictive Index (mAPI) (click to enlarge the image). A positive mAPI greatly increased future asthma probability (eg, 30% pretest probability to 90% posttest probability) http://buff.ly/ZJfMgQ
Can we prevent preschool wheeze progressing to school age asthma?
No. Early use of inhaled corticosteroids does not affect progression of disease. There are no disease modifying drug treatments. Treatment should solely be focused on current symptoms.
What are the treatment strategies for children with preschool wheeze?
- ensure that the home environment is optimal - not exposure to tobacco smoke; parental smoking “not in front of the children” does not protect them from harm
- no drug strategies reduce future risk of asthma
- if inhaled drugs are prescribed, repeated education of the parents in the correct use of spacers is essential. If inhaled drugs in particular do not seem to be working, check that they are being properly administered rather than escalate treatment
How to treat episodic viral wheeze?
Intermittent symptoms should be treated with intermittent therapy (and in practice this is likely to be what parents do anyway).
As needed use: A trial of montelukast in preschool children with troublesome viral induced wheeze is worth attempting (evidence is mixed). Start treatment at the first sign of a viral cold and discontinuing it when the child is clearly better, rather than for a fixed period of days.
How to prevent wheezing?
Regular nebulized budesonide does not prevent viral exacerbations of wheeze. No evidence to support the use of inhaled corticosteroids in children with episodic viral wheeze.
I would be unwise to go above a fluticasone dose of 150 µg twice a day, given the number and duration of viral colds in normal preschool children and the risk of side effects including growth suppression and adrenal failure with higher doses.
No evidence to support the use of regular inhaled corticosteroids in preschool children who do not wheeze between viral colds.
However, in those children with severe episodic wheeze who require repeated admission to hospital or have prolonged disruptive symptoms managed at home, a trial of prophylactic inhaled corticosteroids can be given for 6-8 weeks.
How should we treat multiple trigger wheeze (MTW)?
Step 1: Trial of inhaled corticosteroids or montelukast for a defined period, 4-8 weeks)
Step 2: Stop treatment.
Step 3: Restart treatment if symptoms recur; then reduce treatment to the lowest level that controls symptoms.
Algorithm for the diagnosis and management of early childhood asthma, JACI, 2012:
What about asthma action/treatment plans?
Treatment plans outline self management actions to be taken depending on the severity of symptoms and peak flow measurements and are widely recommended. Many physicians may recommend asthma action plans, but there is no evidence of efficacy in school age children.
Asthma Action Plans
- Asthma Action Plan, adapted by Dr. Dimov (PDF)
- Asthma Action Plan, with added common medications, not branded for a specific physician (PDF)
- NIH generic Asthma Action Plan (PDF)
What is the role of nebulized therapy?
There is no role for nebulised therapy to deliver bronchodilator apart from in children too sick to use inhalers. For all other purposes, the evidence is clear that metered dose inhalers (MDIs) and spacers are at least as good as nebulizer, or better.
Nebulizers should not be used in preschool wheeze; inhaled drugs delivered by metered dose inhaler (MDI) and spacer are at least as efficacious.
If inhaled drugs in particular do not seem to be working, check that they are being properly administered rather than escalating treatment (videos demonstrating the correct technique are available from AllergyGoAway.com).
How to Use a Metered Dose Inhaler (MDI) (albuterol, Xopenex, Flovent, Symbicort, Dulera, Alvesco, Qvar). The three videos below show three techniques: with a spacer and without spacer. The videos are by the CDC.
Although several predictive indices for future asthma risk have been proposed, negative predictive value is excellent but positive predictive value is poor.
References
Managing wheeze in preschool children. BMJ 2014;348:g15. (Published 4 February 2014)
http://www.bmj.com/content/348/bmj.g15
Published: 02-05-2014
Updated: 02-07-2014
