A 17-year-old girl is brought to the emergency department due to hemoptysis and severe respiratory distress. The patient has been on several oral antibiotics for pneumonia over the past week and has required numerous similar treatments in the past. She has been coughing up blood for the past day, which has become progressively worse. Temperature is 37.0 C (98.6 F), blood pressure is 90/60 mm Hg, pulse is 120/min, and respirations are 42/min. Pulmonary examination reveals diffusely reduced air flow, rales, and intercostal retractions. Copious red blood is produced while coughing during the examination and progresses rapidly. Despite aggressive management, the patient ultimately expires. An autopsy is performed and a gross lung specimen is shown in the image below:
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Which of the following is the most likely etiology of this patient's hemoptysis?
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This patient's fatal, massive hemoptysis is suggestive of hemorrhage from the bronchial arteries. A common underlying cause of massive hemoptysis is bronchiectasis, as indicated by this patient's autopsy showing thick, widened airways and mucus plugging. Bronchiectasis is often associated with cystic fibrosis and immunodeficiency disorders, which causes chronic and recurrent airway inflammation and infection. This stimulates neovascularization and bronchial artery hypertrophy. The dilated, fragile, and tortuous vessels are in close proximity to the bronchioles and prone to rupture with increased airway pressure, such as during coughing (eg, acute pulmonary exacerbation).
Normally, blood supply to the lungs consists of the pulmonary circulation and the bronchial circulation. Pulmonary arteries deliver deoxygenated blood from the right ventricle to the lung parenchyma (ie, respiratory bronchioles to alveoli) to be oxygenated and returned to the heart; bronchial arteries arise from the aorta and supply the endobronchial tree (ie, bronchi to terminal bronchioles) with oxygenated blood. Although bleeding from the low-pressure pulmonary circulation is more common, hemorrhage from the high-pressure, systemic bronchial circulation is usually responsible for massive, life-threatening hemoptysis.
(Choices B and C) Hemoptysis due to hypertrophied pulmonary arteries or diffuse alveolar hemorrhage (ie, alveolar capillary vasculitis) involves bleeding from the pulmonary circulation, which is a low-pressure system that is unlikely to result in life-threatening hemoptysis. In addition, bronchiectasis is not associated with either condition.
(Choice D) A fistula between the tracheobronchial tree and aorta is usually fatal and can occur with chronic vascular or airway inflammation, typically due to an implanted medical device or stent. A fistula is an uncommon cause of hemoptysis that would not cause dilated bronchial walls on pathology.
(Choice E) Carcinoid tumors are highly vascular endobronchial tumors that commonly present with hemoptysis. However, autopsy would show a discrete mass (not bronchiectasis).
Educational objective:
Massive, life-threatening hemoptysis is typically due to hemorrhage from the high-pressure bronchial circulation. Bronchiectasis is a common etiology because chronic airway inflammation causes hypertrophied bronchial arteries that are prone to rupture with coughing.