Asthma

Asthma is a chronic inflammatory airway disease marked by reversible bronchoconstriction, airway hyperreactivity, and episodic symptoms like wheeze, cough, and chest tightness.

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Definition

Asthma is a chronic respiratory condition characterised by:

• Variable airflow limitation

• Bronchial hyperresponsiveness

• Reversible airway obstruction

💡 Symptoms often worsen at night or early morning and may fluctuate based on triggers.

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Pathophysiology

Asthma involves persistent eosinophilic airway inflammation, which triggers:

• Bronchoconstriction (early phase)

• Oedema, mucus secretion (late phase)

• Long-term airway remodelling if not treated early

💡 Inflammation is present even when patients are asymptomatic.

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Risk Factors & Triggers

Type	Examples
Genetic	Atopy, family history, eczema
Environmental	Dust mites, pet dander, tobacco smoke
Occupational	Isocyanates, flour, wood dust
Other	Viral infections, cold air, exercise, NSAIDs, beta-blockers

Asthma is commonly part of the atopic triad: asthma, eczema, and allergic rhinitis.

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Clinical Features

• Polyphonic expiratory wheeze

• Cough (esp. nocturnal or early morning)

• Chest tightness

• Breathlessness

• Symptom variability

• Relief with bronchodilators

🚨 Fixed symptoms with no reversibility → consider differential (e.g. COPD, bronchiectasis)

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Diagnosis

Test	Purpose
FeNO	Marker of eosinophilic inflammation
Spirometry	↓ FEV1/FVC ratio (<70%)
Bronchodilator Response	Reversibility (≥12% + 200 mL ↑ FEV1)
PEF Monitoring	≥20% variability over 2 weeks
Peak Flow Diary	Useful for ongoing monitoring

💡 Diagnosis can often be made based on clinical probability + 1–2 objective positive tests.

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Pharmacological Management

Step	Treatment
1	Reliever inhaler (SABA) as needed
2	Add low-dose inhaled corticosteroid (ICS)
3	Add long-acting β2-agonist (LABA) as combo inhaler
4	Increase ICS dose or add LTRA
5	Specialist referral ± LAMA, biologics, or theophylline

💡 Use combination inhalers (ICS + LABA) to improve adherence and reduce exacerbations.

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Non-Drug Measures

• Smoking cessation

• Weight loss if overweight

• Flu & pneumococcal vaccination

• Avoid known allergens or triggers

• Personalised Asthma Action Plan

• Inhaler technique check at every review

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Acute Exacerbation – Red Flags

Severity	Key Features
Moderate	PEFR ≥50–75% predicted, no severe features
Severe	PEFR 33–50%, RR ≥25, HR ≥110, speech limited
Life-threatening	PEFR <33%, SpO₂ <92%, silent chest, confusion

🚨 Normal or rising pCO₂ = late sign of respiratory failure

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Complications

• Respiratory failure

• Pneumothorax

• Status asthmaticus

• Irreversible airway remodelling

• Recurrent hospital admissions

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Fries Tips

• Asthma = variable + reversible + eosinophilic

• Confirm with spirometry + FeNO + bronchodilator response

• SABA overuse (>3/year) = 🚨 poor control

• Review inhaler technique at every visit

• Ask: “Do you wake at night coughing or breathless?”

• Acute attack = O₂ + bronchodilator + steroid ± ipratropium ± magnesium

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🔓 Want full treatment doses, diagrams & discharge checklist?

This is just the high-yield overview. The full Medifries asthma chapter includes:

• Step-by-step acute management algorithms

• Inhaler dose ranges, brands, and device selection tips

• Discharge protocol table with timings and follow-up

• Red flag escalation criteria