What are the causes of hemoptysis (coughing up blood)?

From the Guidelines

Hemoptysis is most commonly caused by acute respiratory tract infections, chronic obstructive pulmonary disease, malignancy, and bronchiectasis, as well as tuberculosis and its sequelae in developing countries, and other causes such as sarcoidosis, autoimmune disease, coagulopathies, and vascular causes like pulmonary arteriovenous malformations 1. The causes of hemoptysis can be categorized into several groups, including:

• Infections: acute respiratory tract infections, tuberculosis, and pneumonia
• Chronic conditions: chronic obstructive pulmonary disease, bronchiectasis, and lung cancer
• Vascular causes: pulmonary arteriovenous malformations, pulmonary pseudoaneurysms, and pulmonary artery aneurysms
• Other causes: sarcoidosis, autoimmune disease, coagulopathies, and sequelae from respiratory infections It is essential to note that the most common causes of hemoptysis vary based on the level of medical care facility and geographic location of the patient, with tuberculosis being a prevalent cause in developing countries 1. The evaluation of hemoptysis should focus on identifying the underlying cause through history, physical examination, imaging studies, and sometimes bronchoscopy, with treatment directed at the specific etiology while managing any significant bleeding. In some cases, the cause of hemoptysis may remain unknown despite extensive investigation, which is termed "cryptogenic hemoptysis" and accounts for approximately 20% of patients initially presenting with hemoptysis 1.

From the Research

Causes of Hemoptysis

• Hemoptysis can be caused by various conditions, ranging from benign to malignant 2
• The most common causes of hemoptysis are:
  • Acute respiratory infections
  • Cancer
  • Bronchiectasis
  • Chronic obstructive pulmonary disease (COPD) 3
• Other causes of hemoptysis include:
  • Chronic bronchitis
  • Lung cancer
  • Vascular malformation
  • Diffuse alveolar hemorrhage
  • Tracheostomy bleed 4, 5
• In some cases, no cause of hemoptysis is identified, which can occur in 20% to 50% of cases 3

Mechanisms of Hemoptysis

• The expectorated blood usually originates from the bronchial arteries 5, 3
• The bronchial arteries are responsible for hemoptysis in 90% of cases 6
• Understanding of pulmonary vascular anatomy is of paramount importance to manage life-threatening hemoptysis 4

Classification of Hemoptysis

• Hemoptysis can be classified according to severity, with mild hemoptysis comprising more than 90% of cases and having a good prognosis, whereas massive hemoptysis has a high mortality rate 3
• Life-threatening hemoptysis is any amount of hemoptysis that causes significant hemodynamic decompensation or respiratory distress which may lead to death if left untreated 4