What is pleural effusion?

Pleural effusion, also called water on the lung, is an excessive buildup of fluid in the space between your lungs and chest cavity.

Thin membranes, called pleura, cover the outside of the lungs and the inside of the chest cavity. There’s always a small amount of liquid within this lining to help lubricate the lungs as they expand within the chest during breathing.

Certain medical conditions can cause a pleural effusion.

Pleural effusions are common, with approximately 1 million cases diagnosed in the United States every year, according to the American Thoracic Society. It’s a serious condition associated with an increased risk of death. In one study, 15 percent of hospitalized people diagnosed with pleural effusions died within 30 days.

Fluid in the chest

How does pleural effusion develop?

The pleura creates too much fluid when it’s irritated, inflamed, or infected. This fluid accumulates in the chest cavity outside the lung, causing what’s known as a pleural effusion.

Certain types of cancer can cause pleural effusions, lung cancer in men and breast cancer in women being the most common.

Other causes of pleural effusions include:

Types of pleural effusions

There are several types of pleural effusions, each with different causes and treatment options. The first classification of pleural effusions is either transudative or exudative.

Transudative pleural effusions

This type is caused by fluid leaking into the pleural space as a result of either a low blood protein count or increased pressure in the blood vessels. Its most common cause is congestive heart failure.

Exudative effusions

This type is caused by:

  • blocked lymph or blood vessels
  • inflammation
  • tumors
  • lung injury

Common conditions that could result in this type of pleural infusion include pulmonary embolisms, pneumonia, and fungal infections.

Complicated and uncomplicated pleural effusions

There are also complicated and uncomplicated pleural effusions. Uncomplicated pleural effusions contain fluid without signs of infection or inflammation. They’re much less likely to cause permanent lung problems.

Complicated pleural effusions, however, contain fluid with significant infection or inflammation. They require prompt treatment that frequently includes chest drainage.

Symptoms and signs of pleural effusion

Some people show no symptoms of pleural effusion. These people usually find out they have the condition through chest X-rays or physical examinations done for another reason.

Common symptoms of pleural effusion include:

See your doctor immediately if you have symptoms of pleural effusion.

Diagnosing pleural effusion

Your doctor will perform a physical examination and listen to your lungs with a stethoscope. They may also order a chest X-ray to help diagnose pleural effusion. Other possible tests include:

In a pleural fluid analysis, your doctor will remove fluid from the pleural membrane area by inserting a needle into the chest cavity and suctioning the fluid into a syringe. The procedure is called a thoracentesis. This also works as a common procedure to drain the excess fluid from the chest cavity. The fluid will then be tested to determine the cause.

Your doctor may also choose to perform a pleural biopsy, which involves taking a sample of tissue from the pleura. This can be done by inserting a small needle from outside the chest wall into the chest cavity.

If they discover you have a pleural effusion, but they’re unable to diagnose which type, your doctor may schedule a thoracoscopy. This is a surgical procedure that lets the doctor see inside the chest cavity using a fiber-optic camera.

For this procedure, your doctor will make a few small incisions in the chest area while you’re under general anesthesia. Then they’ll insert the camera through one incision and the surgical tool through the other to extract a small amount of fluid or tissue for analysis.

Treating pleural effusion

The underlying cause of the condition and the severity of the effusion will determine treatment.

Draining fluid

Generally, treatment involves draining the fluid from the chest cavity, either with a needle or a small tube inserted into the chest.

You’ll receive a local anesthetic before this procedure, which will make the treatment more comfortable. You may feel some pain or discomfort at the incision site after the anesthetic wears off. Most doctors will prescribe medication to help relieve pain.

You may need this treatment more than once if fluid builds up again.

Other treatments may be necessary to manage fluid buildup if cancer is the cause of the pleural effusion.

Pleurodesis

Pleurodesis is a treatment that creates mild inflammation between the lung and chest cavity pleura. After drawing the excess fluid out of the chest cavity, a doctor injects a drug into the area. The drug is often a talc mixture. This medication causes the two layers of the pleura to stick together, which prevents the future buildup of fluid between them.

Surgery

In more serious cases, a doctor surgically inserts a shunt, or small tube, into the chest cavity. This helps redirect the fluid from the chest into the abdomen, where it can be more easily removed by the body. This may be an option for those who don’t respond to other treatments. Pleurectomy, in which part of the pleural lining is surgically removed, may also be an option in certain cases.

Risks of pleural effusion treatment

Treatment for some cases of pleural effusion may be managed with medication and other supportive care. Most people recover within a few days or weeks. Minor complications from more invasive treatments can include slight pain and discomfort, which often go away with time. Some cases of pleural effusion can have more serious complications, depending on the severity of the condition, cause, and treatment used.

Serious complications can include:

  • pulmonary edema or fluid in the lungs, which can result from draining fluid too quickly during thoracentesis
  • partial collapsed lung
  • infection or bleeding

These complications, while serious, are very rare. Your doctor will help determine the most effective treatment option and discuss the benefits and risks of each procedure.

Pleural effusions and cancer

Pleural effusions can be the result of cancer cells spreading to the pleura. They can also be the result of cancer cells blocking the flow of normal fluid within the pleura. Fluid may also build up as a result of certain cancer treatments, such as radiation therapy or chemotherapy.

Certain cancers are more likely to cause pleural effusions than others, including:

Signs and symptoms often include:

  • shortness of breath
  • cough
  • chest pain
  • weight loss

Pleurodesis is often used as a treatment for the malignant pleural effusions caused by cancer. Your doctor may prescribe antibiotics if you have or are susceptible to an infection. Steroids or other anti-inflammatory medications may reduce pain and inflammation.

In addition to treating the pleural effusion, your doctor will treat the cancer that caused it. Pleural effusions are typically the result of metastatic cancer.

People who are undergoing treatment for cancer may also have compromised immune systems, making them more prone to infections or other complications.

What is the outlook for a pleural effusion?

Pleural effusions can be serious and life-threatening. Most require hospitalized treatment and some require surgery. The time it takes to recover from pleural effusions depends on the cause, size, and severity of the effusion, as well as your overall health.

You’ll begin your recovery in the hospital, where you’ll receive the necessary medication and care to help you begin to recover. Many people report feeling tired and weak in the first week after they’ve been discharged from the hospital. On average, you will see your incision sites from surgery heal within two to four weeks. You’ll require continued care and follow-up once you’re home.