What is a pleural hemorrage?

Pleural hemorrhage is the accumulation of blood in the pleural space, the potential between the visceral pleura covering the lungs and the parietal pleura lining the chest cavity.[1] This space normally contains a small amount of fluid which allows the lungs to expand and contract smoothly during respiration.

Most often, pleural hemorrhages are caused by chest trauma, malignancy (lung cancer), or iatrogenic causes such as central venous catheterization or thoracentesis. Rarely, pleural hemorrhages can occur spontaneously, as can happen in hemophilia or anticoagulation.

In many cases, clinical signs of pleural hemorrhage are nonspecific and can be subtle, making diagnosis challenging.[1] Signs and symptoms may include dyspnea, pleuritic chest pain (which worsens with inspiration and coughing), and decreased breath sounds. Patients with massive pleural hemorrhages can present with hemodynamic instability and signs of hypovolemic shock. Physical examination findings may include dullness to percussion over the affected hemithorax and egophony.

Ultrasound is the initial imaging modality of choice to detect pleural effusion, and it can also help differentiate transudative from exudative pleural effusions based on their appearance. Chest radiography is also useful in diagnosing pleural effusions, but may be less sensitive than ultrasound in detecting small effusions. However, it is more useful for assessing the underlying cause of the effusion, such as heart failure, pneumonia, or malignancy.

The underlying cause of the pleural effusion should be identified to guide further diagnostic work-up and management. Diagnostic thoracentesis should generally be performed to analyze the pleural fluid. Thoracoscopy may be necessary for both diagnostic purposes and to facilitate drainage of the effusion in patients with malignant pleural effusions.

Pleural hemorrhage must be differentiated from pleural effusion, another cause of fluid in the pleural space. Pleural effusions are most often caused by conditions that alter the balance of hydrostatic and oncotic forces across the pleural membrane or by inflammation or infection of the pleural space.[2]