Acute exacerbations of asthma in children can be triggered by exposure to allergens such as dust, pollution, animal hair or smoke, causing a type 1 (IgE-mediated) hypersensitivity reaction. This leads to bronchoconstriction and bronchial oedema.

Rapid deterioration in Sx

In addition, a normal pCO2 in an acute asthma attack indicates exhaustion and should, therefore, be classified as life-threatening.

PC:

• Progressively worsening shortness of breath
• Use of accessory muscles
• Fast respiratory rate (tachypnoea)
• Symmetrical expiratory wheeze on auscultation
• The chest can sound “tight” on auscultation with reduced air entry

Investigations

• To confirm the diagnosis: Peak expiratory flow rate which imporves with bronchodilator Tx
• BTS recommend ABG for patients with O2 sats<92
  • Initially patients will have a respiratory alkalosis as tachypnoea causes a drop in CO2. A normal pCO2 or hypoxia is a concerning sign as it means they are tiring and indicates life threatening asthma. A respiratory acidosis due to high CO2 is a very bad sign in asthma.
  • serial ABGs -At baseline then every hour
• CXR not routinely recommended unless:
  • life-threatening asthma
  • suspected PTX
  • failure to respond to Tx

Management

Admission

• all patients with life-threatening should be admitted in hospital