Which of the following is listed as an extrapulmonary cause of hemoptysis?

• A. Thrombocytopenia
• B. Pulmonary infection
• C. Bronchiectasis
• D. Pulmonary infarction

Answer: (A)

A key idea is that hemoptysis can come from problems inside the lungs or from systemic issues outside the lungs. Thrombocytopenia is a systemic bleeding disorder that lowers platelet counts, so the body’s ability to form a hemostatic plug is impaired. This causes mucosal bleeding throughout the airway, including the bronchial passages, which can manifest as coughing up blood. Since the problem originates outside the lung tissue itself, this is considered extrapulmonary.

By contrast, the other conditions—pulmonary infection, bronchiectasis, and pulmonary infarction—are processes that occur within the lung. They cause hemoptysis through local inflammation, erosion of airways, necrosis, or vascular injury in lung tissue. So they are intrapulmonary causes.