Chronic inflammatory airway disease with variable, reversible airflow obstruction and bronchial hyperresponsiveness.
⚠ Red flags
- Silent chest, cyanosis, exhaustion — life-threatening attack
- SpO₂ <92%, PEFR <33% predicted, RR >25, HR >110
- Inability to complete sentences
- Rising or normalising CO₂ in a tiring patient
Diagnostic criteria
Clinical
- Wheeze, breathlessness, chest tightness, cough — variable, often nocturnal
- Symptoms triggered by exercise, allergens, cold air, viral infection
Investigations
- Spirometry: FEV1/FVC <0.7 with ≥12% and ≥200 mL reversibility post-bronchodilator
- Peak flow variability >20% across 2 weeks
- FeNO ≥25 ppb (eosinophilic asthma)
Scoring tools
- Asthma Control Test (ACT)
- Asthma Control Questionnaire (ACQ)
Investigations
Essential
- Spirometry with bronchodilator reversibility
- Peak flow diary (2-week)
Optional
- FeNO
- Allergy testing (skin prick, specific IgE)
- FBC (eosinophils) for biologic eligibility
- CXR if atypical features or first severe exacerbation
Management
Acute
- Salbutamol nebulised 5 mg back-to-back; ipratropium 0.5 mg if severe
- O₂ to keep SpO₂ 94–98%
- Prednisolone 40 mg PO (or hydrocortisone 100 mg IV) for 5 days
- Magnesium sulphate 1.2–2 g IV over 20 min if life-threatening
- Escalate to ICU if exhaustion, silent chest, or rising CO₂
Long-term
- GINA-stepped care; assess control and adherence at every visit
- Step-down once stable for ≥3 months
- Annual asthma review with personalised action plan
Non-pharmacological
- Inhaler technique check and education
- Trigger avoidance (allergens, smoking, occupational exposure)
- Smoking cessation; weight loss if obese
- Vaccinations: annual flu, pneumococcal
Pharmacological
| Drug | Dose | Notes |
|---|---|---|
| ICS/formoterol (MART) | Budesonide-formoterol 200/6 μg 1–2 puffs PRN and BD | GINA-preferred Step 1–4. Both reliever and maintenance. |
| ICS | Beclometasone 200 μg BD | Step up if not controlled; double dose for severe persistent. |
| LABA add-on | Salmeterol 50 μg BD (combined ICS/LABA inhaler) | Never as monotherapy. |
| LAMA add-on | Tiotropium 2.5 μg 2 puffs once daily | Step 4–5 add-on. |
| Anti-IL5/IgE biologic | Mepolizumab / omalizumab per specialist | Severe eosinophilic or allergic asthma after specialist assessment. |
Monitoring
- Asthma Control Test at every review
- Peak flow diary if poor control or recent exacerbation
- Inhaler technique check at every encounter
- Annual review; spirometry every 2–3 years
Referral criteria
- Diagnostic uncertainty
- Severe asthma (Step 4–5) requiring specialist care
- Frequent exacerbations or oral steroid dependence
- Suspected occupational asthma
Complications
- Status asthmaticus and respiratory failure
- Pneumothorax / pneumomediastinum from severe attack
- Steroid-related side effects with chronic OCS
- Airway remodelling and irreversible obstruction
Special populations
- Pregnancy
- Continue usual asthma therapy — uncontrolled asthma is the bigger risk. ICS, LABA, prednisolone all considered acceptable.
- Renal impairment
- No major dose adjustment for inhaled therapy. Caution with magnesium in severe AKI.
- Hepatic impairment
- Most inhaled drugs safe; theophylline clearance reduced.
- Elderly
- Differentiate from COPD; check inhaler technique often. Watch ICS-related candidiasis and osteoporosis.
- Paediatric
- Use age-appropriate spacer; review every 3–6 months. Avoid high-dose ICS without specialist input.