many potential causes

half of all children will wheeze before schooll age

continuous, musical sound due to intrathoracic obstruction

contributing factors:

  • small phsyical size of respiratory system

  • developing immune system

  • Environmental

    • exposure to tobacco

      • both before and after birth

    • damp homes

    • dust mites

    • pets

    • food allergies

    • air pollution

    • infections

Inhaled foreign body

  • acute onset wheeze

  • dry cough

  • decreased lung sounds

  • symptoms begin after episode of choking or severe coughing

    • not always observed

    • children may not volunteer information

  • if delayed:

    • dyspnoea

    • wet cough with sputum production

  • serious complications:

    • pneumonia

    • pneumothorax

    • subglottic oedema

    • more likely if diagnosis ≥24hrs post inhilation

  • long term complications:

    • recurrent pneumonia

    • lung abscesses

    • bronchiectasis

      • more common longer diagnosis delayed

Bronchiolitis

  • acute infection fo lower respiratory tract

  • most common in winter

  • usually caused by RSV

  • tachypnoea, cough, hyperinflation

  • fine inspiratory crackles are likely

  • short tight cough

  • airway secretions play a signifiant role in obstruction

  • fever present

    • high-grade fever may indicate another diagnosis

      • pneumonia

      • wheeze rare with bacterial pneumonia

  • most common cuase of wheeze aged 1-6mo

  • by 10mo incidence much lower

  • rare after 1yr

Episodic viral wheeze

  • non-atopic wheeze

  • associated iwth viral URTI

  • do not usually display respiratory symptoms between episdoes

  • rhinovirus, corona viras, human metapnumovirus, parainfluenze virus, adenovirus

  • symptoms:

    • acute wheeze

    • dyspnoea

    • usualy with cough

  • shortly after viral urti

  • unlikely to have chest crackels

  • bronchiolitis = single episode

    • compared to recurrent infections

  • common 10mo - 3yo

  • usually have fewer episodes over time

  • most children without concurrent atopy will grow out of their symptoms

  • some -> go on to have confirmed asthma

Atopic wheeze

  • aka multiple trigger wheeze

  • recurrent/persistent wheeze

  • associated atopic features

  • multiple exacerbating factors

    • cold iar

    • night time

    • exercise

    • allergen exposure

  • symptoms occur without viral illness

    • more severe exacerbations with viral illness

    • bilateral, widespread wheeze and/or rhonchi

      • most prominent on exhalation

    • cough,

    • dyspnoea

    • prolonged expiration

    • increased RR

    • chest tightness

child with recurrent wheeze with sings of atopy/eczema, + skin-prick tests, family hsitory of asthma/atopy can be considered to have atopic wheeze

  • unusual in child \<2yo

  • dominant orm of wheeze after 3yo

  • almost all children with atopic wheeze go on to be diagnosed with asthma

Transient infant wheeze

  • epidemiological term for self-limiting wheeze

  • aged up to 3yo

  • used in literature to describe group who grow out of wheeze

  • cliniclaly unable to differentiate between wheeze

Assessment

  • history

    • define wheeze

    • nautre/duration

      • constant/intermittent

    • other respiratory symptoms

    • exacerbating factors/triggers

    • previous episodes

    • smoking

    • eczema/atopy - personal & family

  • examination

    • gneeral assessment

    • concurrent upper resp tract signs

    • hyperinflation/respiratory distress

  • investigation

    • CXR

      • symptoms since birth

      • unusually severe wheeze

      • doens’t repsond to treatment

      • unusual clincial features

    • PEFR, Spiro,

      • not used under age of 5

      • not consistent

Management

Lifestyle interventions

  • smoking cessation

  • adress exacerbating factors

    • damp housing

    • heating

  • infection preventing strategies

    • immunisation

    • influenza vaccine

    • hand wahsing

    • good hygiene practise

  • Allergen avoidance

Treating acute episode of wheeze

Bronchodilators

  • bronchiolitis

    • not generally treated with bronchodilators

      • provide minimal benefit

  • episodic viral wheeze/atopic wheeze \<5yo

    • trialed on bronchodilators

  • SABA 100mcg prn (up to 800mcg/day)

  • spacer + mask

  • LABA not recommended as few strong studies

  • Theophylline not recommended

Oral corticosteroids

  • if require hospitalisation

    • recommended

    • given while awaiting transfer

  • if not hospitalisaiont

    • not clear

    • clincial judgement

    • evidence of efficacy limited

      • conflicting

      • most studies focus on older children

  • back-pocket corticosteroids not recommended

    • not shown to prevent exacerbations or hosptial admisison in this group

  • prednisolone 1-2mg/kg /day for 3d

  • adverse effects:

    • appetitie

    • mood

    • behaviour changes

    • > 3mo

      • reduced growth

      • changes to skin

      • muscle weakness

      • Cushing’s syndrome

      • bone wewakening

      • increase risk of DM

Prevention between episodes

Inhaled corticosteroids

  • atopic wheeze

    • consider ICS

  • episodeic viral wheeze

    • ICS less effective

    • not recommended

  • symptom control only

  • no effect of long-term natural history of condition

  • doens’t reduce likelihood that child will develpop persistent wheeze or progress to asthma over time

  • repsonese less thatn that seen in older children

  • ICS \< 5yo = fluticasone 50-100mcg bd via spacer for up to 3 mo

  • ICS should be stopped (after tapering) rather than just reduced once interval symptoms resolve

  • adverse effects;

    • reducedd height (may persist) - 1cm

    • Adrenal suppression

Montelukast

  • leukotriene receptor antagonist

  • apporpirate treatment for symptom and exacearbation control inc children with wheeze of any type

    • “off label”

  • continuous use of montelukast appears to moderately decrease episodes of wheeze and

  • intermittent use

    • when first signs of URTI may help control sypmtoms and reduce # of visiits to GP

  • used alone or alongside ICS

    • to avoid having to increase dose of ICS

  • chewable tablet

  • 2-5yo = 4mg od

  • ideal duration unknown

  • 12mo continuous treatment appears to be effective in preventing exacerbation and controlling interval symptoms

  • short-term dosing - 7d cycles also effective

  • no clinically relevant adverse effects have been reported in children taking montelukast

  • special authrity

    • \<5yo

    • intermittent severe wheezing

    • at least 3 episodes of acute wheeze in previous 12 mo severe enough to seek medical attention