Empyema is a health condition that affects the space between the outermost layer of the lungs and the inner lining of the chest wall, known as the pleural space. This space exists to help the lungs expand and contract.

The pleural space naturally contains a small amount of fluid. Empyema happens when extra fluid begins to collect there.

Different strains of bacteria cause fluid and pus to build up in the pleural space. Often, pneumonia causes empyema.

In this article, learn about the symptoms, causes, and risk factors for empyema, as well as the treatment options.

Symptoms of empyema may include:

  • having pneumonia that does not improve
  • a fever
  • chest pain
  • a cough
  • pus in mucus
  • difficulty breathing
  • a crackling sound in the chest
  • decreased breathing sounds
  • a dull sound when tapping chest

On an X-ray, a healthcare professional may be able to see the buildup of fluid in the area.

Without treatment, empyema can progress through three stages:

Stage 1: Simple empyema

Another name for this stage is the exudative phase. It occurs when extra fluid begins to build up in the pleural cavity. This fluid can become infected and may contain pus.

Stage 2: Complicated empyema

Another name for this stage is the fibrinopurulent phase. The fluid in the pleural cavity begins to thicken and form “pockets.”

Stage 3: Frank empyema

Finally, the infected fluid causes scarring on the inner layers of the lungs. This causes difficulty breathing, as it keeps the lungs from inflating properly. Another name for this stage is the organizing phase.

Pneumonia is the most common cause of empyema. Anyone who has undergone chest surgery may also have a risk of empyema if bacteria enter the wound.

The main risk factor for empyema is recent pneumonia.

Others include:

  • being older than 70
  • having a recent hospital stay
  • having had chest surgery or trauma

In low-risk populations, empyema is generally less severe more likely to develop outside of a hospital.

People with the following conditions are also more likely to develop empyema.

Intravenous drug use may also be a risk factor for simple empyema.

The first step is a chest X-ray, though it can only show a certain amount of fluid in the pleural cavity.

If there is not this amount, but the doctor suspects the presence of excess fluid, they perform an ultrasound. Ultrasounds are more sensitive and so better able to show any extra fluid in the area.

Also, CT scans can show pockets of liquid in the pleural cavity.

Treatment for empyema can include:

Antibiotics

Antibiotics are the first treatment for simple empyema. Because different strains of bacteria may be responsible, finding the right antibiotic is crucial.

The treatment typically takes 2–6 weeks to work.

Drainage

Draining the fluid is essential to prevent simple empyema from progressing. It also helps keep the condition under control.

To drain the fluid, a doctor performs a tube thoracostomy, which involves inserting an ultrasound- or computer-guided tube into the chest cavity and removing the liquid from the pleural space.

Surgery

For advanced cases, surgery may be the best treatment option. One study found that a procedure called decortication yielded better results than tube drainage in people with advanced empyema.

Decortication involves removing the pus pockets and fibrous tissue from the pleural space, which helps the lungs expand.

For draining the fluid, there are two options. In most cases, a surgeon performs a video-assisted thoracotomy (VATS), which is less invasive than the alternative. VATS also involves less pain and a shorter recovery period.

The other option is an open thoracotomy, which requires a surgeon to open the chest.

There are no specific criteria that guide the choice of procedure. One study found that people who had experienced empyema symptoms for less than 4 weeks had better results from surgery than those who had experienced the symptoms for longer.

Fibrinolytic therapy

A doctor may also recommend taking drugs called fibrinolytic agents to drain pleural fluid, in combination with a tube thoracostomy.

A 2018 study that assessed the effectiveness of VATS surgery, compared with fibrinolytic therapy, after tube thoracostomy found that both methods were highly effective.

Possible complications of empyema include:

  • Fibrosis: Damaged lung tissue can cause difficulty breathing that affects a person’s quality of life. If this difficulty continues for 6 months after the infection, decortication surgery may help.
  • Empyema necessitatis: This involves the infection extending into the chest wall and soft tissue. It is very rare and requires immediate medical attention.

Receiving a diagnosis and treatment early can stop empyema from becoming more severe.

The best approach depends on the stage of the condition. Antibiotics and drainage are the first steps, followed by surgery, in more advanced cases.