Pleural Effusion

A pleural effusion is a build up of fluid in the space between the outside covering of the lung and the inside lining of the chest wall (pleura). There are two layers of pleura – an inner layer and an outer layer – which normally have a small amount of fluid between them to help the lungs move easily during breathing. Too much fluid can build up and cause breathing problems.

Causes

A pleural effusion can be caused when cancer cells spread to the pleural cavity (malignant pleural effusion). The types of cancers that may cause pleural effusions are:

• breast
• lung
• ovarian
• lymphoma
• leukemia
• mesothelioma
• melanoma
• various gastrointestinal and genitourinary tract cancers

Not all pleural effusions are malignant. Some are caused by infections (pneumonia), heart failure or blood clots in the lung (pulmonary emboli).

Symptoms

The built up fluid in the pleural space presses on the lung and makes it difficult for the lung to expand properly. This causes the symptoms associated with pleural effusion:

• shortness of breath (dyspnea)
• dry cough
• chest pain or heaviness
• collapsed lung

Diagnosis

Tests that help diagnose pleural effusions include:

• chest x-ray
• computed tomography (CT, CAT) scan of the chest
• ultrasound of the chest
• fine-needle aspiration (FNA) to remove a small amount of fluid from the effusion to send to the laboratory for microscopic examination

Treatment

Pleural effusions are usually associated with more advanced cancer or progressive disease, although it may also be the first sign of cancer. The goals of treatment are to:

• relieve symptoms by draining the fluid (thoracentesis)
• slow the build up of fluid (pleurodesis)
• treat the cancer causing the pleural effusion, depending on the:
  • type of cancer
  • previous treatment
  • severity of symptoms
  • prognosis
  • person's preferences

Pleural effusions frequently recur after treatment and may need retreating.

Thoracentesis

• a small area on the chest is frozen with a local anesthetic
• a small cut is made in the skin
• a hollow needle is inserted through the skin, between the ribs and into the chest wall
• excess fluid is removed from the pleural cavity
• the fluid may be
  • slowly drained all at once
  • drained over a longer period of time
  • drained intermittently as fluid reaccumulates
• other devices can be used to drain the fluid:
  • a plastic tube (catheter) (intrapleural catheter) may be inserted and attached to a drainage device
  • an implanted device (port) may be inserted and pleural fluid drained by a home care nurse
  • a chest (thoracostomy) tube may be inserted during a thoracoscopy and attached to a drainage receptacle
• a sample of the fluid may be tested in a laboratory for cancer cells
• the lung usually re-expands once the fluid has been drained
• a chest x-ray is usually done to see how well the lung has drained and re-expanded and to ensure that a pneumothorax has not occurred

Pleurodesis

• used when fluid tends to reaccumulate in the pleural cavity
• a chest tube is inserted into the pleural cavity to drain excess fluid
• a pleural sclerosing agent is inserted into the pleural space to seal the two layers of pleura together, which prevents fluid from building up again
• the agent is inserted into the chest tube and the tube is clamped for a period of time
• the person may be asked to change position to help distribute the agent
• sclerosing agents are irritating chemicals and may include:
  • bleomycin
  • doxycycline
  • minocycline
  • talc
• pain relievers (analgesics) are often given
• the chest tube is unclamped and allowed to drain into a drainage device or is attached to suction
• the procedure may be done over several days

Surgery

• only done occasionally
• a tube is surgically inserted between the pleural cavity and the abdominal (peritoneal) cavity (pleuroperitoneal shunt)
• fluid drains from the pleural cavity to the peritoneal cavity where it can be removed more easily
• the shunt contains a valve that needs to be pumped frequently to prevent it from plugging
• part of the pleura may be surgically removed (pleurectomy) in some cases

Chemotherapy

• may be used to treat the underlying cancer that is causing pleural effusion, if the cancer is responsive to chemotherapy
  • the choice of drugs will depend on the type of cancer
• hormonal therapy may be used to treat hormonally-responsive cancers

Radiation therapy

• not one of the main treatments for pleural effusions
• may be used to treat lymphoma or lung cancers