What is Hemoptysis
Hemoptysis is the expectoration of blood from the lung alveoli or airways of the lower respiratory tract. 1
Definition and Clinical Significance
Hemoptysis must be distinguished from pseudohemoptysis, which originates from nasopharyngeal or gastrointestinal sources rather than the lower respiratory tract. 2
The condition represents a clinical symptom with a wide differential diagnosis ranging from benign, self-limited causes to life-threatening emergencies. 3
Blood originates primarily from bronchial arteries in most cases of hemoptysis. 2
Classification by Severity
Massive (Life-Threatening) Hemoptysis
Massive hemoptysis is defined as hemoptysis placing the patient at high risk for asphyxiation or exsanguination, with volume thresholds varying from >100 mL to >300-400 mL of expectorated blood in 24 hours. 1, 4
The rate of bleeding is more important than the absolute volume for determining morbidity and mortality risk. 1, 4
Fatal massive hemoptysis results more commonly from asphyxiation rather than exsanguination, as retained blood in the lungs compromises gas exchange. 1
Massive hemoptysis carries mortality rates of 50-100%, particularly in patients with underlying lung cancer. 4, 3
Nonmassive Hemoptysis
Mild hemoptysis (<30 mL/24 hours) comprises more than 90% of cases and is self-limited with good prognosis. 4, 2
Moderate to severe hemoptysis ranges from 30-300 mL in 24 hours. 4
Common Causes (Geographic and Setting-Dependent)
In Outpatient Primary Care Settings
- Acute respiratory tract infections are the most common cause. 1
- Chronic obstructive pulmonary disease (COPD) is a frequent etiology. 1
- Malignancy accounts for a significant proportion of cases. 1
- Bronchiectasis is commonly identified. 1
In Tertiary Referral Centers (North America/Europe)
- Bronchiectasis is the leading cause. 1
- Respiratory infections remain common. 1
- Lung carcinomas are frequently identified. 1
In Developing Countries
- Tuberculosis and its sequelae remain the most prevalent cause of hemoptysis globally. 1
Additional Important Causes
- Sarcoidosis and autoimmune diseases causing pulmonary capillaritis or cavitation. 1
- Coagulopathies. 1
- Vascular causes including pulmonary arteriovenous malformations, pulmonary pseudoaneurysms, and pulmonary artery aneurysms. 1
- Pulmonary embolism is an uncommon cause of hemoptysis. 1
Cryptogenic Hemoptysis
Approximately 20% of patients have no identifiable cause despite extensive investigation with CT and bronchoscopy, termed "cryptogenic hemoptysis." 1
Some studies report rates as high as 50%, though this is likely inflated due to incomplete diagnostic workup. 1
Critical Clinical Pitfalls
Difficulty in clinically quantifying hemoptysis exists due to discordance between expectorated blood and blood retained within the lungs. 1
Concomitant hypotension serves as an independent factor in determining massive hemoptysis severity. 1
Two or more opacified lung quadrants on frontal chest radiograph correlate with increased risk of mortality. 1, 4
The amount of blood loss resulting in death varies based on coexisting cardiopulmonary comorbidities. 1