Life-threatening hemoptysis is defined as > 8 mL per kg every 24 hours. Massive bleeding can cause hypoxemia by obstructing the airway or filling the alveoli.
Common causes of hemoptysis:
(1) pulmonary infection (tuberculosis, pneumonia, etc)
(2) foreign body aspiration
(3) tracheostomy-related
Causes of massive hemorrhage:
(1) congenital heart disease
(2) an aberrant or anomalous artery (vascular malformation)
Other conditions to consider:
(1) cystic fibrosis
(2) factitious, usually from bite injury of the oral mucosa in a child with psychiatric problems
(3) esophagitis
(4) pulmonary hemosiderosis
(5) bronchial or lung tumor (bronchial carcinoid, bronchial adenoma, mediastinal teratoma, metastasis, primary lung carcinoma)
In almost 20% of patients the cause of the bleeding was not identified during the workup.
