Asthma Management
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Direct answer
Asthma is variable respiratory symptoms plus variable expiratory airflow limitation, confirmed by an improvement in FEV1 of at least 12 per cent and 200 mL after a bronchodilator, or peak-flow variability. Current guideline-recommended management puts every patient on inhaled corticosteroid-containing therapy — the preferred reliever is a low-dose ICS-formoterol combination, and sole short-acting beta-agonist reliever therapy is no longer advised. Acute severe asthma is treated with oxygen, nebulised salbutamol with ipratropium, systemic corticosteroids and, if the response is poor, intravenous magnesium sulphate.
What you must remember
- Diagnosis: bronchodilator reversibility on spirometry (FEV1 rise of 12 per cent and 200 mL or more); if baseline function is normal, use peak-flow variability or bronchial provocation (20 per cent FEV1 fall with methacholine); FeNO and eosinophilia support type-2 inflammation.
- Reliever: as-needed low-dose ICS-formoterol is preferred; a SABA-only regimen increases exacerbation risk, so any SABA use must be paired with ICS.
- Controller: low-dose ICS is the foundation; step up with a higher ICS dose, ICS-LABA, or add-on tiotropium for persistent symptoms.
- Severe asthma despite high-dose ICS-LABA: add-on biologics — omalizumab (anti-IgE), mepolizumab or benralizumab (anti-IL-5 pathway), dupilumab (anti-IL-4 receptor alpha) — chosen by phenotype.
- Acute severe: peak flow 33 to 50 per cent of predicted, cannot complete sentences, respiratory rate 25 or more, heart rate 110 or more; life-threatening markers are peak flow below 33 per cent, SpO2 below 92 per cent, silent chest, cyanosis, exhaustion, arrhythmia and a normal or rising PaCO2.
- Acute management: oxygen targeting SpO2 93 to 95 per cent, nebulised salbutamol every 20 minutes in the first hour with ipratropium 0.5 mg, prednisolone 40 to 50 mg for at least five days, and magnesium sulphate 1.2 to 2 g over 20 minutes if response is poor; call critical care for drowsiness or rising PaCO2.
- Control triggers and comorbidities — allergens, tobacco, rhinitis, obesity, GERD, beta-blockers and NSAIDs — check inhaler technique and give a written action plan with annual influenza vaccination.
The first hour of an acute severe attack
A 24-year-old with known asthma reaches the emergency department unable to finish sentences, respiratory rate 30, heart rate 118, peak flow 40 per cent of predicted and SpO2 of 94 per cent. That combination sits in the acute severe band — sick, but not yet life-threatening — and the response follows a fixed order. Sit her upright and give oxygen titrated to 93 to 95 per cent, because over-oxygenation can worsen hypercapnia. Drive nebulised salbutamol with oxygen every 20 minutes through the first hour and add ipratropium 0.5 mg to the early doses. Prednisolone 40 to 50 mg orally goes in early because steroids take hours to act, not minutes. Reassess after 15 to 30 minutes: Drowsiness or a rising PaCO2 means ventilation is imminent — the intensivist makes that call, but spotting it in the stem is what earns the mark.
How the exam frames asthma
Two traps recur year after year. The reliever question is the first: the traditional answer "SABA alone for mild asthma" is now wrong under the ICS-formoterol strategy, so the option offering as-needed low-dose ICS-formoterol beats salbutamol-only even when the stem says "mild, intermittent". The second is grading: a silent chest, SpO2 of 90 per cent, or a comfortably normal PaCO2 in a distressed patient moves the label from acute severe to life-threatening. Asthma versus COPD remains the standard differential, and stems in which poor inhaler technique, rhinitis or GERD explains poor control test whether you search for a cause before stepping up therapy.
Frequently asked questions
What spirometric criterion confirms asthma?
An FEV1 rise of at least 12 per cent and 200 mL after an inhaled bronchodilator, or equivalent peak-flow variability on serial monitoring.
What is the preferred reliever in current asthma management?
As-needed low-dose ICS-formoterol, which treats bronchoconstriction and inflammation together; SABA-only reliever therapy is no longer recommended.
Which features mark an attack as life-threatening?
Peak flow below 33 per cent of predicted, SpO2 below 92 per cent, silent chest, cyanosis, exhaustion, arrhythmia and a normal or rising PaCO2.
When and how is magnesium sulphate given?
As a single intravenous infusion of 1.2 to 2 g over 20 minutes when the response to nebulised bronchodilators and steroids is poor.
Which biologics are used for severe asthma?
Omalizumab binds IgE; mepolizumab and benralizumab target the IL-5 pathway; dupilumab blocks the IL-4 receptor alpha chain.
Why must a SABA-only regimen be abandoned?
Frequent SABA use without ICS leaves inflammation unchecked and increases exacerbations and deaths.