What are the potential causes of hemoptysis in an adult patient?

Causes of Hemoptysis in Adults

Bronchiectasis is the leading cause of hemoptysis in most tertiary referral centers, followed by chronic bronchitis, lung cancer, and respiratory tract infections. 1

Most Common Etiologies

Primary Causes by Frequency

• Bronchiectasis accounts for the majority of cases (26% in prospective studies), particularly in patients with chronic inflammatory conditions, cystic fibrosis, or prior tuberculosis 1, 2
• Chronic bronchitis represents 23% of cases and is more common in smokers 2
• Acute bronchitis causes up to 63% of mild hemoptysis cases, especially those with normal chest radiographs 3, 1
• Lung cancer is the second most common cause in patients with hemoptysis and normal chest radiographs, presenting with hemoptysis in >65% of cases, particularly with centrally-located tumors 1, 4
• Active tuberculosis remains a major cause globally and should be considered in endemic areas or high-risk populations 1, 5
• Nontuberculous mycobacterium accounts for 24% of cases in some series 1

Infectious Causes

• Bacterial pneumonia is particularly common in immunocompromised patients, including those with chronic kidney disease on hemodialysis 1
• Fungal infections, particularly aspergillomas in pre-existing cavities from tuberculosis, cause both acute and recurrent bleeding with high recurrence rates of 55% 1

Malignant Causes

Cancer-Related Hemoptysis

• Bronchogenic carcinoma presents with hemoptysis in 7-10% of patients at initial presentation, with mechanisms including neovascularization, tumor exfoliation exposing blood vessels, tumor necrosis, and airway-vascular fistula formation 3
• Lung cancer should be strongly suspected in patients with occupational carcinogen exposure, smoking history, or age >40 years, even with small amounts of blood-streaked sputum 1, 4
• Metastatic disease to the lungs can cause hemoptysis, though less commonly than primary lung cancer 1

Vascular Causes

Arterial and Venous Abnormalities

• Pulmonary arteriovenous malformations can cause significant bleeding and require embolization 1
• Pulmonary artery aneurysms and pseudoaneurysms are potential sources, particularly in patients with chronic inflammatory disease 1
• Mitral stenosis causes hemoptysis through chronic pulmonary venous hypertension, presenting with classic radiographic findings of elevated left main bronchus and parahilar interstitial infiltrates 1

Systemic and Immune-Mediated Causes

Autoimmune and Inflammatory Conditions

• Immune-complex mediated diseases such as HCV-associated glomerulonephritis can cause pulmonary-renal syndromes with hemoptysis 1
• Autoimmune diseases resulting in capillaritis or cavitation can cause pulmonary-renal syndromes 5
• Sarcoidosis with advanced pulmonary disease causes hemoptysis that typically requires palliative treatment, as these patients are often not surgical candidates 1, 5
• Coagulopathies are additional causes to consider 5

Cryptogenic Hemoptysis

Idiopathic Cases

• No identifiable cause is found in 20-34% of cases despite complete evaluation with CT and bronchoscopy, though these patients often respond well to bronchial artery embolization with 97% remaining free of hemoptysis at 20 months 1, 6
• Cryptogenic hemoptysis has been reported as high as 50%, though this upper range is likely inflated because of incomplete investigation 5

Population-Specific Considerations

Risk Factor Stratification

• Nonsmokers with moderate/severe bleeding or history of tuberculosis are significantly more likely to have bronchiectasis (OR 8.25 for moderate/severe bleeding; OR 16.5 for TB history) 2
• Smokers with hemoptysis are at increased risk for lung cancer and require extensive evaluation with chest CT and bronchoscopy, particularly those with abnormal chest X-rays (OR 5.4 for lung cancer) 2
• Chronic kidney disease patients on hemodialysis have higher rates of respiratory tract infections due to immunocompromised state 1
• Postpartum women should be evaluated for mitral stenosis, as pregnancy increases cardiac output and can precipitate pulmonary hypertension with hemoptysis 1

Geographic Variations

Regional Differences

• The most common causes vary by geographic location and clinical setting, with tuberculosis and its sequelae remaining the leading cause in developing countries, while bronchiectasis, respiratory infections, and lung carcinomas are most common in tertiary referral centers in North America and Europe 5

Uncommon Causes

Rare Etiologies

• Pulmonary embolus is an uncommon cause of hemoptysis, with only single studies reporting it as a primary cause 5