Makindo Medical Notes

💨 Definition: Obstructive lung diseases are characterised by airflow limitation — especially during expiration — due to narrowed, inflamed, or obstructed airways. The hallmark feature is a reduced expiratory flow rate and an FEV₁/FVC ratio < 70%. These disorders impair gas exchange, increase work of breathing, and cause air trapping and hyperinflation. 🫁⚙️

🌈 Common Types

• 🚬 Chronic Obstructive Pulmonary Disease (COPD): Progressive, largely irreversible airflow limitation due to chronic bronchitis and/or emphysema. Most commonly caused by smoking.
• 🌬️ Emphysema: Destruction of alveolar walls → loss of elastic recoil → air trapping and hyperinflation. Classic "pink puffer" phenotype.
• 💦 Chronic Bronchitis: Productive cough for ≥3 months in 2 consecutive years due to mucus gland hypertrophy. Classic "blue bloater" phenotype.
• 🌪️ Asthma: Reversible airway obstruction due to bronchial hyperresponsiveness; often allergic or atopic. Episodic wheeze, cough, and chest tightness.
• 🦠 Bronchiectasis: Irreversible bronchial dilation secondary to chronic infection/inflammation (e.g. post-TB, cystic fibrosis, immunodeficiency).

🩺 Clinical Features

• 😮‍💨 Dyspnoea: Shortness of breath — progressive in COPD and emphysema, episodic in asthma.
• 🤧 Cough: Productive in chronic bronchitis and bronchiectasis; dry in asthma or early COPD.
• 🎵 Wheezing: High-pitched expiratory sound from turbulent flow — hallmark of asthma.
• 🫀 Chest Tightness: Common in acute asthma or COPD exacerbations.
• 🌡️ Fatigue, weight loss, and cyanosis: Signs of chronic hypoxia or advanced disease.

🔬 Diagnosis & Investigations

• 📉 Pulmonary Function Tests (PFTs): ↓ FEV₁, normal/↓ FVC → FEV₁/FVC < 0.70 confirms obstruction. Assess reversibility after bronchodilator.
• 💨 Bronchodilator Reversibility Test: ≥12% and ≥200 mL improvement in FEV₁ suggests asthma.
• 🩻 Chest X-ray / CT: Hyperinflation, flattened diaphragm (emphysema); peribronchial thickening (bronchitis); dilated airways (bronchiectasis).
• 🩸 Arterial Blood Gas (ABG): Detects hypoxia, hypercapnia, or respiratory acidosis in severe disease.
• 📏 Peak Expiratory Flow (PEF): Useful for asthma monitoring and diurnal variability assessment.
• 🧬 Special Tests: α₁-antitrypsin levels (early-onset emphysema); sweat chloride test (cystic fibrosis); immunoglobulins (hypogammaglobulinaemia).

📚 Key Disorders and Findings

🧭 Management Principles

• 🚭 Smoking cessation – cornerstone for COPD prevention.
• 💊 Bronchodilators (β₂-agonists, antimuscarinics) and inhaled corticosteroids to reduce inflammation and improve airflow.
• 💉 Vaccinations: Annual influenza and pneumococcal vaccines to reduce exacerbations.
• 🏃‍♀️ Pulmonary rehabilitation: Exercise, breathing retraining, and education to improve quality of life.
• 💧 Hydration and airway clearance techniques in bronchiectasis.
• 🩸 Oxygen therapy: For chronic hypoxaemia (PaO₂ ≤ 7.3 kPa or SaO₂ ≤ 88%).
• 🫀 Monitor for complications: Cor pulmonale, respiratory failure, or pneumothorax.

💡 Teaching Tip: Obstructive = air can’t get out 🌀 (narrowed airways). Restrictive = air can’t get in 🚫 (stiff lungs). Always confirm obstruction with spirometry and assess reversibility with bronchodilators. Early recognition and smoking cessation remain the most powerful interventions. 🌿🫁