From the Guidelines
The most common causes of an exudative pleural effusion are malignancy, pneumonia, tuberculosis, and pulmonary embolism, as these conditions lead to increased vascular permeability or lymphatic obstruction, resulting in the accumulation of protein-rich fluid in the pleural space 1.
Causes of Exudative Pleural Effusion
- Malignancy: direct pleural involvement by tumors like lung cancer, breast cancer, or lymphoma, with breast carcinoma being the second most common cause of malignant pleural effusion 1
- Pneumonia: parapneumonic effusions develop as inflammatory responses to adjacent lung infections, with empyema representing infected effusions requiring drainage
- Tuberculosis: tuberculous pleuritis causes exudates through hypersensitivity reactions to mycobacterial proteins
- Pulmonary embolism: leads to effusions through increased capillary permeability from inflammatory mediators
Other Causes
- Autoimmune diseases (rheumatoid arthritis, lupus)
- Pancreatitis
- Esophageal rupture
- Post-cardiac injury syndrome
Diagnosis and Treatment
Diagnosis typically requires thoracentesis with fluid analysis, including protein, LDH, glucose, cell count, cytology, and microbiological studies to determine the underlying cause and guide appropriate treatment 1. The management of malignant pleural effusions should aim to relieve dyspnea in a minimally invasive manner, with a focus on patient-centered outcomes 1.
From the Research
Causes of Exudative Pleural Effusion
The most common causes of exudative pleural effusion include:
- Malignancy, with lung and breast cancer being the most common types 2, 3, 4, 5, 6
- Pneumonia, with approximately 40% of patients developing a pleural effusion 5
- Pulmonary embolization 5
Malignant Pleural Effusion
Malignant pleural effusion is a common cause of exudative pleural effusion, accounting for up to 50% of exudates in some clinical series 6. The most common types of cancer associated with malignant pleural effusion are:
- Lung cancer, with adenocarcinoma being the most common type 4
- Breast cancer 2, 5, 6
- Lymphomas and leukemias 5
Diagnosis and Treatment
Diagnosis of malignant pleural effusion is typically made through pleural fluid cytology, with immunohistochemical tests used to differentiate between benign and malignant effusions 5, 6. Treatment options include: