What causes pleural effusion
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Causes of Pleural Effusion
Pleural effusion, the accumulation of excess fluid in the pleural cavity, is a common medical condition with a variety of underlying causes. Understanding these causes is crucial for accurate diagnosis and effective treatment.
Common Causes of Pleural Effusion
Congestive Heart Failure and Cirrhosis
Congestive heart failure (CHF) is one of the leading causes of pleural effusion. In CHF, the heart's inability to pump blood effectively leads to fluid accumulation in the lungs, which can overflow into the pleural space1 2. Similarly, cirrhosis with ascites can cause pleural effusion due to the movement of fluid from the peritoneal cavity into the pleural cavity through diaphragmatic pores2.
Infections: Pneumonia and Tuberculosis
Infections are another significant cause of pleural effusion. Pneumonia can lead to pleural effusion in approximately 40% of cases, and if not properly managed, it can progress to empyema, a collection of pus in the pleural space2. Tuberculosis (TB) is also a frequent cause, especially in high-burden settings. TB-related pleural effusion results from a direct infection of the pleural space and an associated immune response6 7.
Malignancies
Malignant pleural effusions are commonly associated with cancers such as lung cancer, breast cancer, and lymphomas. These effusions occur due to the infiltration of cancer cells into the pleural space, leading to fluid accumulation1 2 4. The diagnosis is often confirmed through pleural fluid cytology and immunohistochemical tests2.
Pulmonary Embolism
Pulmonary embolism (PE) can cause pleural effusion by increasing pressure in the pulmonary arteries, leading to fluid leakage into the pleural space. This condition is often associated with exudative effusions, which are characterized by high protein and lactate dehydrogenase (LDH) levels in the pleural fluid1 2.
Rare and Unusual Causes
Black Pleural Effusion
Black pleural effusion is an extremely rare condition that can result from infections (e.g., Aspergillus niger), malignancies (e.g., malignant melanoma), hemorrhage, or the presence of charcoal-containing substances in the pleural space3.
Hydronephrosis
Hydronephrosis, a condition characterized by the swelling of a kidney due to urine buildup, can also lead to pleural effusion. This occurs when the lymphatic drainage from the kidneys is overwhelmed, causing fluid to accumulate in the pleural space5.
Diagnostic Approaches
Transudative vs. Exudative Effusions
Differentiating between transudative and exudative pleural effusions is essential for diagnosis. Transudative effusions are typically caused by systemic factors such as CHF and cirrhosis, while exudative effusions result from local factors like infections and malignancies. This distinction is made by measuring the protein and LDH levels in the pleural fluid2.
Advanced Diagnostic Techniques
Recent advances in metabolomics have identified potential biomarkers for distinguishing between different causes of pleural effusion. For instance, the tryptophan/kynurenine ratio has shown promise in differentiating tuberculous pleural effusion from malignant pleural effusion6.
Conclusion
Pleural effusion can arise from a multitude of causes, including congestive heart failure, infections, malignancies, and rare conditions like black pleural effusion and hydronephrosis. Accurate diagnosis, often involving the differentiation between transudative and exudative effusions, is crucial for effective treatment. Advances in diagnostic techniques continue to improve our ability to identify the underlying causes and tailor appropriate therapies.
Sources and full results
Most relevant research papers on this topic
Pleural Effusion in Adults-Etiology, Diagnosis, and Treatment.
Proper treatment of pleural effusion depends on thorough differential diagnosis, with a wide range of therapeutic options available.
Systematic Review
Highly CitedPleural Diseases
Pleural effusions are common and can be differentiated between transudative and exudative causes by measuring pleural fluid protein and lactic dehydrogenase levels.
Highly CitedBlack pleural effusion.
Black pleural effusions can be classified into four major categories based on the underlying pathophysiological conditions: infection, malignant melanoma, hemorrhage, and other causes.
Systematic ReviewPleural effusion: laboratory tests in 300 cases.
Pleural effusion is most commonly caused by cancer, tuberculosis, and bacterial infection, with cancer diagnosis being established through cytological examination of pleural fluid and tuberculosis diagnosis through culture of pleural fluid.
Observational StudyHighly CitedHydronephrosis as a cause of pleural effusion.
Certain abdominal and retroperitoneal diseases have been associated with pleural effusion without direct extension of the disease into the chest. Among these are ovarian and pelvic tumors (12), pancreatitis and carcinoma of the pancreas (6, 9, 13), cirrhosis of the liver (8, 9), subphrenic abscess (2), and retroperitoneal lymphoma (15). Overburdening of the lymphatic drainage from these organs or interruption of pleural drainage is the usual explanation for this relationship and is probably the main pathologic process. Pleural effusion has also been noted with chronic hereditary lymphedema (7), again implicating the lymphatic system. Experimental work has shown that the pleural cavity receives lymph from below the diaphragm in both health and disease (3, 12, 13). Recently, we have encountered two patients who presented with right-sided pleural effusion and were subsequently found to have hydronephrosis. When the lesions obstructing the outflow of urine were relieved, the pleural effusion abated. This led ...
Case ReportHighly CitedIntegrated semi-targeted metabolomics analysis reveals distinct metabolic dysregulation in pleural effusion caused by tuberculosis and malignancy.
The ratio of tryptophan/kynurenine can effectively distinguish pleural effusion caused by tuberculosis from malignancy, with a sensitivity of 92.7% and specificity of 86.1%.
Observational StudyTuberculous pleural effusions: advances and controversies.
Tuberculous pleural effusions are often diagnosed using induced sputum, but early pleural drainage may be beneficial in selected cases.
Highly CitedThe modern diagnosis and management of pleural effusions
Pleural effusions can be effectively managed in community and secondary care, with ambulatory management becoming increasingly common.
Systematic Review
Rigorous JournalUnilateral Pleural Effusions with More Than One Apparent Etiology. A Prospective Observational Study.
38 (30%) of study subjects had multiple causes for their unilateral pleural effusion, which may help determine optimal treatment and improve patients' symptoms.
Observational StudyInvestigation of a unilateral pleural effusion in adults: British Thoracic Society pleural disease guideline 2010
This guideline aims to establish a diagnosis swiftly while minimising unnecessary invasive investigations and facilitating treatment, avoiding repeated therapeutic aspirations when possible.
Rigorous JournalHighly Cited