Haemoptysis is a common clinical emergency and usually indicates the presence of respiratory, cardiovascular or other systemic disease, which may be a sign of some serious illness and should be taken seriously. It is important to note that the amount of haemoptysis does not always correspond to the severity of the disease.
Sudden haemoptysis is more common in patients with tuberculosis, bronchiectasis or mitral stenosis. Although the disease itself may not be fatal, haemoptysis can lead to a large amount of blood or blood clots blocking the airway and causing asphyxia, which can be life-threatening.