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Chronic Asthma in Children

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Overview

Asthma is a chronic respiratory condition associated with airway inflammation and hyperresponsiveness leading to bronchoconstriction and wheezing. An acute asthma exacerbation describes the onset of severe asthma symptoms which may be life-threatening.

Epidemiology

  • The incidence of asthma is higher in children
  • During childhood, the prevalence of asthma is higher in boys than in girls
  • During adolescence, the prevalence of asthma is around the same in boys and girls
  • In adulthood, the prevalence of asthma is higher in girls than in boys

Risk Factors

Presentation

Patients present with wheezing, cough, breathlessness, or chest tightness:

  • May be diurnal – worse at night or early morning
  • May be triggered – examples are exercise, viral infection, cold air, allergens, emotions and laughter
  • Auscultation shows expiratory wheezing
    • Focal wheezing suggests an inhaled foreign body or tumour

Diagnosis

Overview

For children aged 5-16 years:

  • Spirometry with bronchodilator reversibility (BDR) testing:
    • Spirometry – FEV1/FVC ratio <70% suggests an obstructive picture
    • BDR – an improvement in FEV1 of 12% or more is positive
  • If normal or BDR negative: request fractional exhaled nitric oxide (FeNO) testing:
    • FeNO level ≥35 ppb is positive

For children <5 years:

  • Diagnose clinically

Differential Diagnoses

Bronchiolitis

  • Infants <2 years old present with 1-3 days of fever and coryza followed by:
    • Persistent cough
    • Either tachypnoea, chest recessions, or both
    • Wheeze, crackles, or both

Viral-induced wheeze

  • Wheezing is only triggered by viral infections
  • There may be no history of atopy

Inhaled foreign body

  • Symptoms such as cough present more suddenly
  • Auscultation shows focal wheezing

Management

Children aged 5-16 years old

The management of asthma in children aged 5-16 years old is similar to that of adults:

  • Step 1: newly-diagnosed asthma: short-acting beta agonist (SABA, e.g. salbutamol)
  • Step 2: If symptoms occur ≥3 days a week or night-time waking or symptoms not controlled with SABA alone: SABA + paediatric low-dose inhaled corticosteroid (ICS)
  • Step 3: SABA + paediatric low-dose ICS + leukotriene receptor antagonist (LTRA)
  • Step 4: SABA + paediatric low-dose ICS + long-acting beta-agonist (LABA) + stop LTRA if it is not working at this point
  • Step 5: SABA + change ICS or LABA to maintenance and reliever therapy (MART) that includes paediatric low-dose ICS
  • Step 6: SABA + MART that includes paediatric moderate-dose ICS or paediatric moderate-dose ICS + separate LABA
  • Step 7: SABA + one of:
    • High-dose paediatric ICS either as a fixed-dose regime or as a MART
    • Trial adding theophylline
    • Seeking help from an asthma specialist

Children <5 years old

  • Step 1: newly-diagnosed asthma: SABA
  • Step 2: If symptoms occur ≥3 days a week or night-time waking or symptoms not controlled with SABA alone: SABA + 8-week trial of paediatric moderate-dose ICS
    • After 8 weeks, stop paediatric moderate-dose ICS and monitor:
      • If symptoms did not resolve – alternative diagnosis likely
      • If symptoms resolved and recurred within 4 weeks of stopping ICS, restart ICS but use low-dose instead
      • If symptoms resolved and recurred beyond 4 weeks after stopping ICS, repeat 8-week trial of paediatric moderate-dose ICS
  • Step 3: SABA + paediatric low-dose ICS + LTRA
  • Step 4: stop LTRA and refer to paediatric asthma specialist

Monitoring

  • Asthma control is monitored at every review. If control is suboptimal:
    • Confirm if the patient is adhering to treatment
    • Review the patient’s inhaler technique
    • Review if treatment needs changing
    • Ask about occupational asthma and/or other triggers

Complications

  • Death
  • Airway remodelling
  • Impaired quality of life

Prognosis

  • Male children are more likely to outgrow asthma during adolescence
  • The earlier the onset of asthma, the better the prognosis. Most children presenting <2 years of age become asymptomatic by 6-11 years

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