Pleural Effusion Overview

A serous membrane covering the lung parenchyma, chest wall, diaphragm, and mediastinum.

The pleural membrane covering the lung surface.

The pleural membrane covering the chest wall, diaphragm, and mediastinum.

The potential space between the visceral and parietal pleurae, containing a thin layer of fluid.

An accumulation of >10 mL of fluid in the pleural space.

A pleural effusion composed mainly of blood.

A collection of chyle (lymphatic fluid) within the pleural space.

Pleural effusions caused by systemic influences on fluid formation or resorption.

Pleural effusions caused by local influences on fluid formation or resorption.

Common causes of fluid buildup in the chest that are due to systemic issues, like heart failure, liver disease, or kidney problems.

X-ray imaging of the chest can detect pleural effusions, but sensitivity depends on the size and location of the fluid. A PA chest x-ray can detect effusions larger than 200mL, while a lateral chest x-ray is more sensitive and can detect as little as 50mL of fluid.

Pleural effusions appear on a chest x-ray as basal opacities obscuring the hemidiaphragm, with a concave upper border.

Ultrasound of the chest is more sensitive than a chest x-ray for detecting and localizing pleural fluid. It can differentiate between pleural fluid and masses or thickening.

CT scans with contrast can help distinguish between benign and malignant pleural disease. Features like nodular thickening, mediastinal involvement, and pleural thickening greater than 1cm strongly suggest malignancy.

Thoracentesis, or pleural fluid aspiration, can be both diagnostic and therapeutic, depending on the amount of fluid removed.

After a thoracentesis, the pleural fluid should be analyzed for different components to help identify the cause of the effusion.

Pleural fluid analysis includes measuring glucose, protein, LDH (lactate dehydrogenase), and performing a cell count to look for malignant cells.

Pleural effusions can be classified as transudates or exudates, which helps narrow down the possible causes.

A pleural effusion is considered an exudate if the pleural fluid protein level is greater than or equal to 30g/L in patients with normal serum protein.

Light's criteria are used to classify pleural effusions as exudates or transudates when borderline cases (protein levels between 25-35g/L) or abnormal serum protein levels are present.

A type of pleural effusion associated with pneumonia, where the pleural fluid is infected.

A severe form of parapneumonic effusion where the pleural space fills with pus.

Initial, sterile pleural effusion that can evolve into a complicated parapneumonic effusion or empyema.

A pleural effusion occurring without preceding pneumonia.

A condition where C-reactive protein (CRP) levels do not significantly decrease within the first 3 days of pneumonia treatment.

A protein/serum protein ratio greater than 0.5 in pleural fluid is a sign of inflammation.

A lactate dehydrogenase (LDH)/serum LDH ratio greater than 0.6 in pleural fluid indicates inflammation.

A pleural fluid LDH level exceeding two-thirds of the upper limit of normal serum LDH suggests inflammation.

A procedure to obtain a sample of pleural tissue for diagnosis of infections and other conditions.

A procedure to obtain a pleural tissue biopsy using imaging guidance or a minimally invasive surgical technique.

A technique that uses sound waves to visualize structures in the chest. It is more sensitive than a chest X-ray at detecting and locating pleural fluid.

A procedure where fluid is removed from the pleural space using a needle. It can be used for both diagnosis and treatment.

A radiographic technique that uses X-rays to create images of the internal structures of the chest. It can detect effusions but sensitivity depends on the size and location of the fluid.

A technique where a portion of pleural tissue is removed to help diagnose the cause of pleural effusion.

A specialized imaging technique using computed tomography that can distinguish between benign and malignant pleural disease, and identify important details about the effusion.

The fluid-filled space between the two layers of the pleura, normally containing a small amount of fluid.

An excess accumulation of fluid in the pleural space, exceeding 10 mL.

Pleural effusions caused by systemic influences like heart failure or kidney disease, affecting fluid formation or reabsorption.

Pleural effusions caused by local influences, like infections or cancer, affecting fluid formation or reabsorption.

A pleural effusion composed mainly of blood, often caused by trauma or internal bleeding.

A pleural effusion containing chyle, a milky fluid from the lymphatic system, often caused by lymphatic duct blockage.

Reduced chest expansion, reduced tactile vocal fremitus, a dull percussion note, and quiet breath sounds are some of the characteristic clinical signs.

A procedure to remove fluid from the pleural space using a needle, helping diagnose and treat the effusion.

Analyzing the fluid obtained from a thoracentesis to identify the cause of the effusion by examining its composition.

These criteria help classify pleural effusions as exudates or transudates based on protein content, LDH levels, and the ratio of fluid to serum protein.

Factors that increase the risk of developing empyema, including diabetes, alcohol abuse, gastro-oesophageal reflux, and intravenous drug abuse.