What are the causes of pleural effusion?

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Last updated: June 16, 2025View editorial policy

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From the Guidelines

Pleural effusion is caused by various conditions that disrupt the balance of fluid production and absorption in the pleural space, with the most common causes including heart failure, malignancies, pneumonia, pulmonary embolism, and tuberculosis, as reported in the most recent study by 1. The causes of pleural effusion can be categorized into transudative and exudative effusions, with transudative effusions usually reflecting a systemic etiology and exudative effusions resulting from a process localized to the pleura, as noted in 1. Some key points to consider when evaluating pleural effusion include:

  • The most frequent causes of pleural effusion are heart failure, malignancy, pneumonia, tuberculosis, post-surgery, pericardial diseases, and cirrhosis, as stated in 1.
  • A careful history and physical examination of the patient remains the most important first step when evaluating someone with an undiagnosed pleural effusion, as emphasized in 1.
  • Thoracic ultrasound (TUS) is a valuable diagnostic tool and should be performed on every patient at their initial presentation and again whenever a pleural procedure is being performed, as recommended in 1.
  • Diagnosis typically requires thoracentesis to analyze the fluid and determine the underlying cause, which guides appropriate treatment, as mentioned in 1. It is essential to consider the patient's symptoms, general health, and functional status when deciding on the best course of treatment, as discussed in 1 and 1. In terms of treatment, options may include therapeutic thoracentesis, chest tube drainage, and chemical pleurodesis or thoracoscopy with talc poudrage, as described in 1 and 1. The choice of treatment depends on the underlying cause of the pleural effusion, the patient's overall health, and the presence of any contraindications to certain procedures, as noted in 1 and 1. Overall, the management of pleural effusion requires a comprehensive approach that takes into account the underlying cause, the patient's symptoms and overall health, and the potential risks and benefits of different treatment options, as emphasized in 1 and 1.

From the Research

Causes of Pleural Effusion

The causes of pleural effusion can be varied and are often categorized into transudates and exudates. Some of the most common causes include:

  • Congestive heart failure 2, 3, 4, 5, 6
  • Cirrhosis 2, 3
  • Pneumonia 2, 3, 4, 6
  • Malignancy 2, 3, 4
  • Tuberculosis 2, 3
  • Lupus erythematosus 2
  • Rheumatoid disease 2
  • Chylothorax 2
  • Pulmonary embolism 3, 4
  • Kidney failure 3

Transudative and Exudative Effusions

Transudative effusions are often caused by congestive heart failure, cirrhosis, and kidney failure, while exudative effusions are commonly caused by malignancy, pneumonia, and pulmonary embolism 3, 4. The differentiation between transudates and exudates is crucial for further diagnostic work-up and treatment.

Diagnostic Approach

A diagnostic approach to pleural effusion involves determining whether the patient has a transudate or an exudate, and then guiding the evaluation based on the patient's history and physical examination 3. Diagnostic thoracentesis is often required to differentiate between transudates and exudates, and to guide further treatment. Point-of-care ultrasound and chest radiography are also useful tools in evaluating the pleural space and guiding thoracentesis 3, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pleural effusions.

The Medical clinics of North America, 2011

Research

Pleural Effusion: Diagnostic Approach in Adults.

American family physician, 2023

Research

Pleural Effusion in Adults-Etiology, Diagnosis, and Treatment.

Deutsches Arzteblatt international, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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