Empyema is also called pyothorax or purulent pleuritis. It’s a condition in which pus gathers in the area between the lungs and the inner surface of the chest wall. This area is known as the pleural space. Pus is a fluid that’s filled with immune cells, dead cells, and bacteria. Pus in the pleural space can’t be coughed out. Instead, it needs to be drained by a needle or surgery.
Empyema usually develops after pneumonia, which is an infection of the lung tissue.
Empyema can develop after you have pneumonia. Many different types of bacteria may cause pneumonia, but the two most common are Streptococcus pneumoniae and Staphylococcus aureus. Occasionally, empyema may happen after you’ve had surgery on your chest. Medical instruments can transfer bacteria into your pleural cavity.
The pleural space naturally has some fluid, but infection can cause fluid to build up faster than it can be absorbed. The fluid then becomes infected with the bacteria that caused the pneumonia or infection. The infected fluid thickens. It can cause the lining of your lungs and chest cavity to stick together and form pockets. This is called an empyema. Your lungs may not be able to inflate completely, which can lead to breathing difficulties.
The biggest risk factor for empyema is having pneumonia. Empyema occurs most frequently in children and older adults. However, it’s fairly uncommon. In one study, it occurred in less than 1 percent of children with pneumonia.
Having the following conditions can also increase your chances of empyema after pneumonia:
- chronic obstructive pulmonary disease (COPD)
- rheumatoid arthritis
- a weakened immune system
- surgery or recent trauma
- lung abscess
Empyema can be simple or complex.
Simple empyema occurs in the early stages of the illness. A person has this type if the pus is free-flowing. The symptoms of simple empyema include:
- shortness of breath
- dry cough
- chest pain when breathing that may be described as stabbing
- loss of appetite
Complex empyema occurs in the later stage of the illness. In complex empyema, the inflammation is more severe. Scar tissue may form and divide the chest cavity into smaller cavities. This is called loculation, and it’s more difficult to treat.
If the infection continues to get worse, it can lead to the formation of a thick peel over the pleura, called a pleural peel. This peel prevents the lung from expanding. Surgery is required to fix it.
Other symptoms in complex empyema include:
- difficulty breathing
- decreased breath sounds
- weight loss
- chest pain
- high fever
- rapid breathing
- fast heart rate
- low blood pressure
A collapsed lung can cause sudden, sharp chest pain and shortness of breath that gets worse when coughing or breathing.
These conditions can be fatal. If you have these symptoms, you should call 911 or have someone drive you to an emergency room.
A doctor may suspect empyema if you have pneumonia that isn’t responding to treatment. Your doctor will take a complete medical history and physical examination. They may use a stethoscope to listen for any abnormal sounds in your lungs. Your doctor will usually perform certain tests or procedures to confirm a diagnosis:
- Chest X-rays and CT scans will show whether or not there’s fluid in the pleural space.
- An ultrasound of the chest will show the amount of fluid and its exact location.
- Blood tests can help check your white blood cell count, look for the C-reactive protein, and identify the bacteria causing the infection. White cell count can be elevated when you have an infection.
- During a thoracentesis, a needle is inserted through the back of your ribcage into the pleural space to take a sample of fluid. The fluid is then analyzed under a microscope to look for bacteria, protein, and other cells.
Treatment is aimed at removing the pus and fluid from the pleura and treating the infection. Antibiotics are used to treat the underlying infection. The specific type of antibiotic depends on what type of bacteria is causing the infection.
The method used to drain the pus depends on the stage of the empyema.
In simple cases, a needle can be inserted into the pleural space to drain the fluid. This is called percutaneous thoracentesis.
In the later stages, or complex empyema, a drainage tube must be used to drain the pus. This procedure is usually performed under anesthesia in an operating room. There are different types of surgery for this:
Thoracostomy: In this procedure, your doctor will insert a plastic tube into your chest between two ribs. Then they’ll connect the tube to a suction device and remove the fluid. They may also inject medication to help drain the fluid.
Video-assisted thoracic surgery: Your surgeon will remove the affected tissue around your lung and then insert a drainage tube or use medication to remove the fluid. They will create three small incisions and use a tiny camera called a thoracoscope for this process.
Open decortication: In this surgery, your surgeon will peel away the pleural peel.
The outlook for empyema with prompt treatment is good. Long-term damage to the lungs is rare. You should finish your prescribed antibiotics and go in for a follow-up chest X-ray. Your doctor can make sure your pleura has healed properly.
However, in people with other conditions that compromise the immune system, empyema can have a mortality rate as high as 40 percent.
If it’s not treated, empyema can lead to potentially life-threatening complications such as sepsis.