A pleural effusion, often described as fluid around the lungs, occurs when excess fluid builds up in the pleural space surrounding the lungs.
A pleural effusion develops in the pleural space, the small area between the two thin layers of tissue (the pleura) that surround the lungs. Normally, this space contains only a small amount of fluid that helps the lungs move smoothly during breathing. When too much fluid accumulates, it can place pressure on the lungs and make it more difficult for them to fully expand.
Pleural effusions can develop for many different reasons, including infections, heart conditions, cancer, inflammation, or underlying lung disease. Some people experience few symptoms, while others develop shortness of breath, chest discomfort, or other breathing-related symptoms. Pleural effusions can affect people of all ages and may occur as a result of many different medical conditions.
Thoracic surgeons at WashU Medicine
Lung surgeons and interventional pulmonologists at WashU Medicine see patients with pleural space diseases at Barnes-Jewish Hospital, one of the top hospitals in the nation for lung disease care, as well as convenient locations across the region.
What Is a pleural effusion?
A pleural effusion occurs when excess fluid collects in the pleural space, the area between the lungs and the chest wall. Because the pleural space normally contains only a small amount of lubricating fluid, additional fluid can build pressure around the lungs and affect normal breathing.
Pleural effusions vary in size and severity. Small pleural effusions may cause few or no symptoms and may be discovered incidentally during imaging studies. Larger pleural effusions can place more pressure on the lungs and may lead to increasing symptoms.
Doctors often classify pleural effusions based on the type of fluid and the underlying cause. Common categories include:
- Transudative pleural effusions: Often caused by conditions that affect fluid balance in the body, such as heart failure
- Exudative pleural effusions: Often associated with inflammation, infection, cancer, or lung disease
- Malignant pleural effusions: Fluid buildup related to cancer affecting the pleura or surrounding structures
Identifying the cause of a pleural effusion helps guide treatment decisions.
What are the symptoms of pleural effusion?
Symptoms of a pleural effusion can vary depending on how much fluid has accumulated and the underlying cause. Some people have no symptoms, while others develop breathing difficulties as fluid increases around the lungs.
Common symptoms of pleural effusion may include:
- Shortness of breath
- Chest pain or chest pressure
- Cough
- Difficulty taking deep breaths
- Fatigue
- Fever in some cases
Symptoms may gradually worsen as more fluid collects around the lungs.
What causes pleural effusion?
A pleural effusion can develop for many reasons. In some cases, excess fluid results from conditions elsewhere in the body. In others, inflammation, infection, or disease directly affects the lungs or pleura.
Common causes and risk factors include:
- Heart failure
- Pneumonia or lung infections
- Cancer
- Inflammatory conditions
- Pulmonary embolism
- Liver disease
- Kidney disease
- Certain underlying lung disorders
Determining the cause of the fluid buildup is an important part of diagnosis and treatment planning.
How Is pleural effusion diagnosed?
Diagnosing a pleural effusion usually begins with a review of symptoms, medical history, and a physical examination. Because fluid around the lungs can occur for many reasons, identifying the underlying cause is an important part of evaluation.
Tests used to diagnose pleural effusion may include:
- Chest X-ray: Can help identify fluid buildup around the lungs
- CT scan: Provides more detailed images of the lungs and pleura
- Ultrasound: Often used to detect fluid and help guide procedures
- Laboratory testing: Blood tests may help evaluate possible causes
- Thoracentesis: A procedure used to remove and analyze pleural fluid
The results of these tests help determine both the amount of fluid present and the cause of the pleural effusion.
How Is pleural effusion treated?
Treatment for pleural effusion depends on the amount of fluid present, the underlying cause, and the severity of symptoms.
Treatment options may include:
- Observation and monitoring: Small pleural effusions may only require follow-up and monitoring
- Treating the underlying condition: Addressing infections, heart conditions, or other causes may help reduce fluid buildup
- Thoracentesis: Removing fluid can help relieve symptoms and assist with diagnosis
- Chest tube drainage: Larger fluid collections may require ongoing drainage
- Pleural procedures or surgery: Some patients with recurrent or complex pleural effusions may require additional treatment
The goal of treatment is to improve breathing, relieve symptoms, and prevent fluid from returning whenever possible.
What are the potential risks and complications of pleural effusion?
The risks and complications of pleural effusion vary depending on the cause, amount of fluid, and overall health of the patient. Some pleural effusions resolve with treatment, while others may become more serious if left untreated.
Potential complications of pleural effusion may include:
- Progressive shortness of breath
- Increasing pressure on the lungs
- Infection involving pleural fluid
- Recurrent fluid buildup
- Reduced lung expansion and function
- Complications related to the underlying disease causing the effusion
Because fluid around the lungs can occur for many reasons, medical evaluation is important for determining the cause and developing an appropriate treatment plan.
Early diagnosis and treatment can often improve symptoms and help reduce complications.
