- Chronic lung diseases such as bronchiectasis, chronic bronchitis, and bronchiectasis lead to persistent airway inflammation and damage to bronchial blood vessels, making them predisposing factors for haemoptysis.
- These diseases cause increased bronchial arterial pressure and friability, resulting in recurrent bleeding episodes.
- In contrast, conditions like pulmonary embolism and tuberculosis cause haemoptysis as acute events rather than a predisposing state.
- Similarly, mitral stenosis may lead to pulmonary hypertension but is less directly associated with chronic airway bleeding.
- Therefore, chronic lung disease is a key predisposing factor due to ongoing airway vascular damage.

Reference: Davidson’s Principles and Practice of Medicine, 24th Edition, Chapter: Diseases of the Respiratory System, Page 786.