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
- Personal or family history of atopy (e.g. asthma, eczema, allergic rhinitis, allergic conjunctivitis)
- Respiratory infections in infancy
- Pre- and postnatal exposure to tobacco smoke
- Prematurity
- Low birth weight
- Obesity
Presentation
- Shortness of breath over hours-days
- Tachypnoea
- Increased use of reliever inhalers
- Auscultation may show:
- Diffuse expiratory wheezing – focal wheezing suggests a foreign body
- Reduced air entry
- Silent chest – life-threatening as it suggests severe bronchoconstriction and very little air entry
Assessment of Severity
British Thoracic Society (BTS)/Scottish Intercollegiate Guidelines Network (SIGN) guideline
A category is met if any of the following apply:
- Moderate asthma:
- Oxygen saturations (SpO2) on room air ≥92%
- No clinical features of severe asthma
- Acute severe asthma:
- SpO2 <92%
- Too breathless to talk
- Heart rate:
- >125 /min if >5 years
- >140 /min if 1-5 years
- Respiratory rate:
- >30 /min if >5 years
- >40 /min if 1-5 years
- Use of accessory neck muscles
- Life-threatening asthma
- SpO2 <92% and any of:
- Silent chest
- Poor respiratory effort
- Agitation
- Confusion
- Cyanosis
- SpO2 <92% and any of:
Management
All patients
- Any child with severe or life-threatening asthma should immediately be referred to hospital.
- Oral prednisolone should be given for 3-5 days in all children with an asthma exacerbation
Mild-moderate acute asthma
- 1st-line: 1 puff of a short-acting beta-2 agonist (SABA) via a spacer every 30-60 seconds up to 10 puffs
- If symptoms are not relieved, continue SABA and refer to hospital
Moderate-severe acute asthma
- Oxygen if SpO2 <94% or working hard to breathe
- SABA
- Nebulisers with SABA or a short-acting muscarinic antagonist (ipratropium)
- Oral prednisolone or IV hydrocortisone if unable to retain oral medication (e.g. vomiting)
- If control is not attained by this point, seek senior help and consider transferral to a paediatric intensive care unit (PICU):
- IV magnesium sulphate may be considered
- IV salbutamol may be considered
- IV aminophylline may be considered
- Intensive care admission, intubation, and ventilation
Follow Up
- Acute asthma should always be followed up with:
- A careful history to identify any triggers
- Checking inhaler technique and current treatment
- A written asthma action plan aimed to prevent relapse, optimise treatment, and prevent seeking help
- The patient’s GP should be notified within 24 hours of discharge and the patient should be seen within 2 working days.
- Patients with a near-fatal asthma attack should be followed up by a specialist indefinitely.