Hemoptysis

Hemoptysis is the expectoration of blood from the lower respiratory tract—the tracheobronchial tree or pulmonary parenchyma. It is a symptom, not a diagnosis. Acute bronchitis, COPD, bronchiectasis, pulmonary tuberculosis, and primary lung cancer are common causes in adults; pulmonary embolism, pneumonia, trauma, and medication-related bleeding are other possibilities. The immediate danger is not determined by colour alone or by the amount lost from the circulation. Blood can obstruct the airway, impair ventilation, and reduce oxygen exchange before it causes major blood loss. Bleeding is often supplied by bronchial arteries, which carry systemic-pressure blood, so a pulmonary bleed can become brisk and difficult to control. Respiratory compromise can deteriorate rapidly, making timely assessment and intervention critical. Use “massive” or “life-threatening” hemoptysis for bleeding greater than 200 mL in 24 hours, at least 100 mL per hour, or any amount that causes airway obstruction, hypoxia, or hemodynamic instability. Volume estimates are often imprecise. A patient who is becoming hypoxic or unable to clear blood is high priority even if the measured volume is below a numerical threshold.