Asthma In Children

Asthma is a chronic inflammatory airway disease characterized by variable respiratory symptoms and variable expiratory airflow limitation. Airway inflammation, bronchial hyperresponsiveness and reversible bronchoconstriction produce recurrent wheeze, cough and breathlessness.

Diagnosis is more difficult below 5 years because recurrent viral wheezing is common and reliable spirometry may not be possible. Recurrent wheeze, interval symptoms, nocturnal symptoms, exercise induced symptoms, atopy and a family history of asthma increase diagnostic probability.

Typical features include:

• Recurrent wheeze
• Cough, particularly nocturnal or early morning
• Breathlessness
• Exercise induced symptoms
• Prolonged expiration
• Variable symptoms triggered by viral infections, allergens, smoke or cold air

Severe exacerbation is suggested by:

• Inability to speak or feed normally
• Marked accessory muscle use
• Central cyanosis
• SpO₂ below 90%
• Altered consciousness
• Exhaustion
• Markedly reduced air entry
• Silent chest

A silent chest is a preterminal sign of critically restricted airflow.

Asthma is a clinical diagnosis supported by evidence of variable airflow obstruction.

In children able to perform reliable spirometry, assess expiratory airflow limitation and bronchodilator reversibility.

In preschool children, diagnosis depends more heavily on recurrent symptom pattern, interval symptoms, atopic features, response to treatment and exclusion of alternative causes.

Important alternatives include:

• Bronchiolitis
• Foreign body aspiration
• Chronic aspiration
• Tuberculosis
• Bronchiectasis
• Congenital airway disease
• Cardiac disease

Acute exacerbation

Give inhaled salbutamol promptly.

For children 5 years and younger:

Salbutamol 4 puffs of 100 micrograms via pMDI and spacer, increasing to 6 puffs in severe exacerbation, or 2.5 mg nebulised.

For moderate or severe exacerbation, repeat approximately every 20 minutes for 3 doses, then reassess.

Give oxygen in significant hypoxaemia, targeting approximately SpO₂ ≥94% during acute treatment, with adjustment for altitude where relevant.

For moderate or severe exacerbation:

Prednisolone 1 to 2 mg/kg PO once daily for 3 to 5 days

Maximum:

• 20 mg/day if younger than 2 years

• 30 mg/day at age 2 to 5 years

Alternative:

Dexamethasone 0.3 to 0.6 mg/kg PO, maximum 12 mg, using a short course regimen.

For moderate to severe exacerbation add:

Ipratropium bromide 250 micrograms nebulised every 20 minutes for 3 doses, or 4 puffs of 20 micrograms via pMDI and spacer.

In severe exacerbation with inadequate response, consider:

Magnesium sulfate 40 to 50 mg/kg IV over 10 to 20 minutes, maximum 2 g, particularly in children aged 2 years or older.

Escalate urgently for worsening hypoxaemia, exhaustion, silent chest, reduced consciousness or rising carbon dioxide.

For recurrent asthma, inhaled corticosteroid containing therapy is the foundation of long term control. Before escalating treatment, check diagnosis, adherence, inhaler technique, spacer use, environmental smoke exposure and comorbid allergic disease.