Respiratory Disorders at a Glance
| Disorder | Aetiology (Cause) | Core Pathology | Hallmark Symptoms | Lung Volume Changes | Reversible? |
|---|---|---|---|---|---|
| Asthma | Allergens, exercise, infection → airway inflammation, bronchospasm | Reversible narrowing of bronchi/bronchioles; mucus hypersecretion | Wheezing, breathlessness, expiratory difficulty | ↑RV (air trapping), ↓FEV1 | Yes (bronchodilators) |
| Emphysema | Chronic smoking (most common) → protease-mediated alveolar wall destruction | Irreversible loss of alveolar walls and elastic tissue | Progressive dyspnoea, barrel chest, reduced exercise tolerance | ↑RV, ↑TLC, ↑FRC, ↓VC, ↓FEV1 | No |
| Silicosis | Chronic inhalation of silica (SiO2) dust — mining, stone cutting, sandblasting | Macrophage-mediated lung fibrosis; thickened alveolar walls | Progressive dyspnoea, reduced lung compliance, cough | ↓TLC, ↓VC (restrictive) | No |
| Asbestosis | Long-term inhalation of asbestos fibres — construction, shipbuilding | Lung fibrosis + pleural plaques | Progressive dyspnoea, dry cough | ↓TLC, ↓VC (restrictive) | No |
Key Distinctions for NEET
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Asthma vs Emphysema: Asthma is reversible (airway narrowing); emphysema is irreversible (structural alveolar destruction). Barrel chest is emphysema, not asthma.
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Silicosis vs Asbestosis: Both cause fibrosis. Asbestosis additionally carries a high risk of mesothelioma (pleural cancer) and lung cancer. Different causative agents: silica vs asbestos fibres.
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Obstructive vs Restrictive pattern: Asthma and emphysema = obstructive (↑RV, ↓FEV1/FVC). Fibrotic diseases = restrictive (↓TLC, ↓VC, preserved FEV1/FVC ratio).