Acute exacerbation of asthma

Acute exacerbations of asthma are characterized by episodes of progressive increase in shortness of breath, cough, wheezing or chest tightness. Severe exacerbations are potentially life-threatening, and treatment requires close supervision and often ICU admission. It usually occurs due to exposure to factors like exercise, air pollution, allergens, or infections.

Clinical features

Patients present with dyspnoea, accessory breathing muscles, chest tightness. They can usually not complete sentences in one breath. They usually have wheezing on auscultation, but the chest can also be silent on auscultation, in which case the situation is life threatening.

ABG shows hypocapnia with normoxaemia or hypoxaemia.

Management

Most cases can be treated with supplemental oxygen, bronchodilators, and systemic glucocorticoids. Magnesium sulphate can be given IV as a smooth muscle relaxant, but the evidence is not strong. Admission to the ICU is indicated if:

• If conservative therapy doesn’t work
• PaO2 < 60 mmHg
• History of near-fatal asthma
• Peak expiratory flow rate < 30%

In the ICU, bronchodilators can be repeated as IV. NIV may be attempted, but invasive ventilation has better evidence and is therefore more used. It’s important to look for and treat the underlying problem.