Understanding Pleural Effusions

Annakay Newell, Danielle Haak, Christianlly Cena
  • Author
    Annakay Newell

    Annakay Newell has taught in the biological and environmental science fields for over ten years. She has a PhD in plant pathology from the University of Georgia, a MSc in plant pathology from the University of Arkansas and a BSc in Biology from the University of Arkansas Pine Bluff.

  • Instructor
    Danielle Haak

    Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

  • Expert Contributor
    Christianlly Cena

    Christianlly has taught college Physics, Natural science, Earth science, and facilitated laboratory courses. He has a master's degree in Physics and is currently pursuing his doctorate degree.

Define and understand pleural effusion. Explore pleural effusion signs and symptoms as well as potential pleural effusion complications. Discover types of pleural effusions and treatments for them. Updated: 11/02/2021

Pleural Effusion Definition

The pleura are layers of serous membrane that line the thorax and cover the lungs. The pleural cavity, also called the chest of the thoracic cavity, is the space above the diaphragm enclosed by the spine, ribs, and sternum (breastbone). The pleura allows the lungs to expand and contract during breathing properly. An effusion is the outpouring of fluid or the occurrence of too much fluid. The pleural cavity generally holds a few milliliters of pleural fluid in an average human. A pleural effusion is the abnormal accumulation of fluid between the layers of the pleura, which points to an imbalance in the production and elimination of pleural fluid. A pleural effusion can have many causes, such as congestive heart failure and pneumonia, and can be life-threatening if not properly managed. Pleural effusions are diagnosed approximately 1.5 million times in the United States annually.

About Pleural Effusions

Our bodies require just the right balance of fluids to function properly - imagine how painful it would be if our organs were dry and rubbing against one another as we move. Ouch! However, sometimes imbalances develop, causing there to be too much or too little lubrication, and this is when problems occur.

The lungs and the inside of the chest wall are lined by a membrane called the pleura. Naturally, a small cavity forms in between the chest wall and the lungs called the pleural space. There is usually a small amount of fluid in the pleural space to allow the lungs to move as we breathe, but a pleural effusion occurs when too much fluid accumulates here. This can hinder movement and place extra pressure on the surrounding organs. A pleural effusion may also be referred to as an effusion or a pulmonary effusion.

Chest x-ray of a pleural effusion. Arrow A shows fluid layering in the right pleural cavity, and B is the normal width of the lung in the cavity.

Chest x-ray of a pleural effusion

Pleural Effusion Causes & Diagnosis

The most common causes of pleural effusions are congestive heart failure, cancer, bacterial pneumonia, and pulmonary embolism. There are, however, many illnesses that can cause a pleural effusion to manifest, such as:

  • Liver disease such as Cirrhosis
  • Kidney disease
  • Cancer
  • Tuberculosis
  • Heart surgery
  • Inflammatory disease
  • Infections
  • Certain medications
  • Radiation therapy
  • Chemotherapy
  • Abdominal surgery
  • Hypoalbuminemia
  • Trauma

Some rare diseases are associated with pleural effusions, such as rheumatoid arthritis, Langerhans-cell granulomatosis, systemic lupus erythematosus, Wegener disease, Meigs syndrome, Chylothorax, and Ovarian hyperstimulation syndrome.

Pleural effusion is usually suspected upon physical examination of a patient. Breath sounds during a physical exam, along with patient history, can usually serve as a guide to further testing. A chest x-ray is usually obtained if a pleural effusion is suspected to confirm whether it is uni or bilateral. A chest ultrasound and computerized tomography (CT) are also used to diagnose or distinguish various aspects of pleural effusions. A diagnostic puncture to obtain fluid of a pleural effusion is often used to do cytological, microbiological, and biochemical analyses.

Risk factors for pleural effusion include smoking, drinking alcohol, underlying disease, or a history of contact with asbestos.

Pleural Effusion Signs and Symptoms

Pleural effusion symptoms can vary widely across individuals. Some people have no symptoms, while others may experience shortness of breath or labored breathing (Dyspnea), difficulty breathing when not erect (Orthopnea), and coughing (usually dry and nonproductive). Symptoms are also correlated with the amount of fluid buildup. For example, individuals with a large amount of buildup may find it harder to breathe than those with a smaller amount. Inflammation of the lung can also occur, resulting in chest pain. Fever and weight loss are also seen in some cases. Pleural effusion signs include a collection of fluid in the abdomen (ascites), yellowish nails, unilateral lower extremity swelling or lymphedema, and pericardial friction rub.

Pleural Effusion Complications

The complications of pleural effusion can be life-threatening depending on what caused it, patient history, and how quickly it was diagnosed and treated. Some of these complications are:

  • Sepsis: when the chemicals released to fight infection causes inflammation throughout the entire body
  • Pneumothorax: lung collapse
  • Empyema: pus within the pleural space
  • Lung scarring
  • Permanent decrease in lung function

Types of Pleural Effusions

Pleural effusions are characterized as exudative or transudative based on their cause and the type of fluid built up in the pleural cavity.

Transudative or Uncomplicated Pleural Effusion

Transudative pleural effusion is caused by systemic conditions resulting in fluid leakage into the pleural space. This can be caused by an increase in blood pressure or low blood protein. This type of pleural effusion is most common in people with heart failure. It is often called uncomplicated pleural effusion because it is easier to treat and generally has fewer complications than exudative pleural effusions.

Exudative or Complicated Pleural Effusion

Exudative pleural effusion is caused by inflammatory conditions or local cellular damage. It can be related to the leakage of bacteria across blood vessels and is usually associated with lymph vessels, tumors, inflammation, infection, or lung injury. It is usually harder to treat and can present more complications than transudative pleural effusions and therefore is often referred to as complicated pleural effusion. Exudative pleural effusion can cause permanent lung damage.

Unilateral and Bilateral Pleural Effusions

Pleural effusions are classified as unilateral or bilateral based on the presence of fluid in one or both lungs. Unilateral pleural effusions occur in one lung and bilateral pleural effusions occur in both.

Pleural Effusion Treatments

Pleural effusions are usually treated by treating their cause. For example, if it is caused by congestive heart failure, a treatment regimen with diuretics is traditionally prescribed. Physicians typically do this because treating the root cause can decrease the likelihood that the fluid buildup will return.

Pleural Effusion Medication & Pleurodesis

  • Steroids or Non-steroidal anti-inflammatory drugs: these drugs usually relieve fever and pain and reduce swelling
  • Diuretics: help to rid the body of salt and water and is used when the cause is heart failure
  • Antibiotics: used to treat bacterial infections
  • Bronchodilators: help to widen the airways and allow more oxygen flow

Pleurodesis is a medical procedure that removes the space between the lung and chest wall by suctioning the fluid from the chest through a tiny incision and using talc powder to attach them. This procedure usually prevents the recurrence of fluid buildup. Medication can also be delivered into the pleural cavity through the pleurodesis procedure. This treatment is most common in cases where there is an infection.

Diagram showing where pleural effusions form
pleural effusion

Types and Causes of Pleural Effusions

You might not think there's much to know about pleural effusions, but there are two types of categorization doctors might use classify them. The first is an effusion that is transudative or exudative. A transudative effusion is one where the fluid in the pleural space is similar in composition to the normal fluid found there. This type of effusion can be caused by congestive heart failure. An exudative effusion is one where the fluid in the pleural space has excess proteins, blood or indicates there is an infection or inflammation. This type can be caused by conditions like lung cancer or pneumonia.

Pleural effusions can also be classified as uncomplicated or complicated. An uncomplicated effusion is one where the analysis of fluid shows no indication of infection or inflammation, whereas a complicated effusion is one where the fluids show signs of inflammation or infection. This is problematic because the fluid can eventually harden in the pleural space, threatening the lung's ability to function. Complicated effusions need to be drained before permanent lung damage occurs while uncomplicated effusions are unlikely to cause permanent lung damage.

In general, effusions may be caused by congestive heart failure, kidney failure, kidney disease, low albumin levels in the blood, infection, cancer, a pulmonary embolism, cirrhosis of the liver, an injury or trauma, pneumonia, or an autoimmune disease.

Symptoms of Pleural Effusions

Sometimes there aren't any symptoms associated with a pleural effusion, especially if it's small. However, as you can imagine, if the effusion is large, this can cause serious problems. Who wants excess fluids sitting in their chest where all the important stuff is located? When symptoms are present, they can include chest pain, difficult or painful breathing (especially deep breathing), coughing, fever, chills, loss of appetite, and hiccups.

If not treated, pleural effusions can lead to collapsed lungs, scarring, a buildup of pus in the pleural space, blood infections, or extra air in the chest cavity.

Treatment Options

Pleural effusions are typically diagnosed through a physical exam and some type of imaging scan (like an X-ray, CT scan, etc.). Small pleural effusions may go away on their own, but larger ones may need some type of action. If an underlying cause is to blame, treating it may cure the effusion.

A thoracentesis is a procedure where a small tube is inserted into the pleural effusion to manually drain the excess fluid away. However, these are one-time procedures and the tube is removed afterwards. For more serious or chronic cases, a chest tube may be inserted. Again, a tube is inserted to drain the fluid, but it stays put for a longer period of time. For very long-term treatment, a pleural drain may be inserted. This tube stays in place allowing long-term draining.

A thoracentesis procedure is used to manually drain a pleural effusion.
thoracentesis procedure

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Additional Info

About Pleural Effusions

Our bodies require just the right balance of fluids to function properly - imagine how painful it would be if our organs were dry and rubbing against one another as we move. Ouch! However, sometimes imbalances develop, causing there to be too much or too little lubrication, and this is when problems occur.

The lungs and the inside of the chest wall are lined by a membrane called the pleura. Naturally, a small cavity forms in between the chest wall and the lungs called the pleural space. There is usually a small amount of fluid in the pleural space to allow the lungs to move as we breathe, but a pleural effusion occurs when too much fluid accumulates here. This can hinder movement and place extra pressure on the surrounding organs. A pleural effusion may also be referred to as an effusion or a pulmonary effusion.

Diagram showing where pleural effusions form
pleural effusion

Types and Causes of Pleural Effusions

You might not think there's much to know about pleural effusions, but there are two types of categorization doctors might use classify them. The first is an effusion that is transudative or exudative. A transudative effusion is one where the fluid in the pleural space is similar in composition to the normal fluid found there. This type of effusion can be caused by congestive heart failure. An exudative effusion is one where the fluid in the pleural space has excess proteins, blood or indicates there is an infection or inflammation. This type can be caused by conditions like lung cancer or pneumonia.

Pleural effusions can also be classified as uncomplicated or complicated. An uncomplicated effusion is one where the analysis of fluid shows no indication of infection or inflammation, whereas a complicated effusion is one where the fluids show signs of inflammation or infection. This is problematic because the fluid can eventually harden in the pleural space, threatening the lung's ability to function. Complicated effusions need to be drained before permanent lung damage occurs while uncomplicated effusions are unlikely to cause permanent lung damage.

In general, effusions may be caused by congestive heart failure, kidney failure, kidney disease, low albumin levels in the blood, infection, cancer, a pulmonary embolism, cirrhosis of the liver, an injury or trauma, pneumonia, or an autoimmune disease.

Symptoms of Pleural Effusions

Sometimes there aren't any symptoms associated with a pleural effusion, especially if it's small. However, as you can imagine, if the effusion is large, this can cause serious problems. Who wants excess fluids sitting in their chest where all the important stuff is located? When symptoms are present, they can include chest pain, difficult or painful breathing (especially deep breathing), coughing, fever, chills, loss of appetite, and hiccups.

If not treated, pleural effusions can lead to collapsed lungs, scarring, a buildup of pus in the pleural space, blood infections, or extra air in the chest cavity.

Treatment Options

Pleural effusions are typically diagnosed through a physical exam and some type of imaging scan (like an X-ray, CT scan, etc.). Small pleural effusions may go away on their own, but larger ones may need some type of action. If an underlying cause is to blame, treating it may cure the effusion.

A thoracentesis is a procedure where a small tube is inserted into the pleural effusion to manually drain the excess fluid away. However, these are one-time procedures and the tube is removed afterwards. For more serious or chronic cases, a chest tube may be inserted. Again, a tube is inserted to drain the fluid, but it stays put for a longer period of time. For very long-term treatment, a pleural drain may be inserted. This tube stays in place allowing long-term draining.

A thoracentesis procedure is used to manually drain a pleural effusion.
thoracentesis procedure

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  • Activities
  • FAQs

Pleural Effusion: True or False Activity

This activity will help you assess your knowledge of the causes, symptoms, and treatment of pleural effusion.

Directions

Determine whether the following statements are true or false. To do this, print or copy this page on blank paper and underline or circle the answer.

True | False 1. The pleura is a large membrane that wraps around the outside of the chest wall or cavity.

True | False 2. Collapsed lungs and blood infections result from untreated pleurodesis.

True | False 3. There is a possibility of lung failure when excess fluid hardens in the pleural space.

True | False 4. Complicated effusions can be treated by draining the accumulated fluid in the pleura.

True | False 5. Congestive heart failure is the most common cause of exudative effusion.

True | False 6. Lung cancer may also cause excess fluid in the pleural space.

True | False 7. Some symptoms of pleural effusions include headaches, muscle pain, and confusion.

True | False 8. Pleural effusions caused by infections require antibiotics to be directly injected into the affected region.

True | False 9. Long-term draining of accumulated fluid in the pleural space requires a chest tube.

True | False 10. Pneumonia causes the air sacs of the lungs to inflame, leading to an exudative effusion.


Answer Key

  1. False, because the correct statement is: The pleura is a large membrane that wraps around the inside of the chest wall or cavity.
  2. False, because the correct statement is: Collapsed lungs and blood infections result from untreated pleural effusion.
  3. True
  4. True
  5. False, because the correct statement is: Congestive heart failure is the most common cause of transudative effusion.
  6. True
  7. False, because the correct statement is: Some symptoms of pleural effusions include chest pain, painful breathing, and loss of appetite.
  8. True
  9. False, because the correct statement is: Long-term draining of accumulated fluid in the pleural space requires a pleural drain.
  10. True

What happens if pleural effusion is left untreated?

If a pleural effusion is left untreated, complications such as a permanent decrease in lung function, sepsis, and lung scarring can occur. Death can also be a result.

How do you confirm pleural effusion?

The first step to diagnosing a pleural effusion is a thorough physical examination and patient history. Diagnosis can then be confirmed using a chest x-ray, chest ultrasound, or computerized tomography (CT).

What is the most common cause of pleural effusion?

The most common cause of pleural effusion is heart failure. A pleural effusion can have many other causes, such as congestive heart failure, pneumonia, cancer, and pulmonary embolism.

How is pleural effusion treated?

Pleural effusion is usually treated by treating the underlying cause using medications such as diuretics, steroids or non-steroidal anti-inflammatory drugs, bronchodilators, and antibiotics. It can also be treated using procedures such as thoracentesis, pleurodesis, or the insertion of chest tubes.

Is pleural effusion life-threatening?

Pleural effusion is life-threatening if not quickly diagnosed and treated. Infections can lead to sepsis in some cases and decreased lung function can lead to organ failure and death.

What are the two types of pleural effusion?

The two types of pleural effusions are:

Exudative pleural effusion: is caused by inflammatory conditions or local cellular damage.

Transudative pleural effusion is caused by systemic conditions that result in fluid leakage into the pleural space.

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