Massive Pleural Effusions

Definition and Radiographic Characteristics

Massive pleural effusions are defined as pleural effusions that occupy the entire hemithorax, according to the European Respiratory Society 1, 2
While only approximately 10% of patients with malignant pleural effusions present with massive effusions, malignancy is the most common cause of massive pleural effusions, as reported by the American Thoracic Society 3
The size of pleural effusions correlates with the degree of reduction in breath sounds on physical examination, as noted by clinical guidelines 4

Hepatic hydrothorax can also present with sizeable effusions, as indicated by the European Respiratory Society 5
Massive pleural effusions are associated with significantly worse survival outcomes in patients with malignant pleural disease, according to the European Respiratory Society 1, 2
The pathogenesis of dyspnea in massive pleural effusions involves decreased chest wall compliance, contralateral shifting of the mediastinum, decreased ipsilateral lung volume, and reflex stimulation from the lungs and chest wall, as explained by the American Thoracic Society 3

Chest CT with contrast is recommended for evaluation of massive effusions, particularly to assess for underlying malignancy, as suggested by the National Comprehensive Cancer Network 6