What condition causes bloody sputum?

Bloody sputum primarily indicates hemoptysis, which is the medical term for the coughing up of blood from the respiratory tract. This condition can result from various underlying issues affecting the lungs and bronchi, including infections, lung cancer, chronic bronchitis, and other pulmonary diseases. When blood is present in the sputum, it can vary in amount, color, and consistency, giving important clues about the underlying cause.

While pulmonary embolism can sometimes cause hemoptysis, it is more commonly associated with acute chest pain and shortness of breath rather than exclusively presenting as bloody sputum. Pneumothorax typically would lead to sharp chest pain and respiratory distress, but not specifically bloody sputum. Heart failure may lead to respiratory issues, but the sputum would more likely be frothy and pink due to pulmonary edema, not simply bloody. Thus, hemoptysis is the most precise term for the presence of blood in sputum, making it the correct choice in this context.