It is a condition in which pus collects in the area between the lungs and the inner surface of the chest wall.
Pus is a fluid-filled with immune cells, dead cells, and bacteria. The pus in the pleural space cannot be expelled. Therefore it needs to be drained with a needle or surgery.
It is also called pyothorax or purulent pleurisy and usually develops after pneumonia, an infection of the lung tissue.
Empyema can develop after you have pneumonia. Many different types of bacteria can cause pneumonia, but the two most common are Streptococcus pneumonia and Staphylococcus aureus.
Occasionally, empyema may appear after you have 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 liquid then becomes infected with the bacteria that caused pneumonia or infection.
The infected fluid thickens. It can cause the lining of the lungs and chest cavity to stick together and form pockets. This is called empyema. Your lungs may not be able to inflate, which can lead to breathing difficulties fully.
The most significant risk factor for empyema is pneumonia. Empyema occurs most often in children and older adults. However, it is pretty rare. One study 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.
- Rheumatoid arthritis.
- A weakened immune system.
- Recent surgery or trauma.
- Lung abscess
Empyema can be simple or complex.
Simple empyema occurs in the early stages of the disease. A person has this type if the pus flows freely. Symptoms of simple empyema include:
- Difficulty breathing.
- Dry cough.
- Chest pain when breathing can be described as stabbing.
- Loss of appetite
Complex empyema occurs in the later stage of the disease. In complicated empyema, the inflammation is more severe. Scar tissue can form and divide the chest cavity into smaller cavities. This is called loculation and is more challenging to treat.
If the infection worsens, it can cause a thick layer to form over the pleura, called the pleural shell. This shell prevents the lung from expanding. Surgery is required to fix it.
Other symptoms in complex empyema include:
- Difficult breathing
- Decreased breath sounds.
- Chest pain.
In rare cases, a case of complex empyema can lead to more severe complications. These include sepsis and a collapsed lung, also called a pneumothorax. Symptoms of sepsis include:
- High fever.
- A cold.
- Fast breathing.
- Fast heart rate
- Low blood pressure.
A collapsed lung can cause sudden, sharp chest pain and shortness of breath, which is worse by coughing or breathing.
These conditions can be fatal. If you have these symptoms, you should call 911 or have someone take you to the emergency room.
A doctor may suspect empyema if you have pneumonia that does not respond to treatment. Your doctor will take a complete medical history and physical exam.
They can use a stethoscope to listen to any abnormal sounds in your lungs. Your doctor will usually perform specific tests or procedures to confirm a diagnosis:
- Chest X-rays and CT scans will show whether or not there is fluid in the pleural space.
- A chest ultrasound will show the amount of liquid and its exact location.
- Blood tests can help check the white blood cell count, look for C-reactive protein, and identify the bacteria causing the infection. Your white blood cell count can go up when you have an infection.
- During a thoracentesis, a needle is inserted through the back of the rib cage into the pleural space to take a sample of fluid. The fluid is then analyzed under a microscope to look for bacteria, proteins, and other cells.
Treatment aims to remove pus and fluid from the pleura and treat the infection. Antibiotics are used to treat the underlying condition. The specific type of antibiotic depends on the type of bacteria causing the infection.
The method used to drain the pus depends on the stage of the empyema.
A needle can be inserted into the pleural space to drain the fluid in simple cases. This is called percutaneous thoracentesis.
In the later stages of complex empyema, a drainage tube should be used to drain the pus. This procedure is usually done 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. They will then connect the line to a suction device and draw the fluid out. They may also inject medicine 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 medicine to remove the fluid. You will create three small incisions and use a small camera called a thoracoscope for this process.
Open decortication: Your surgeon will peel the pleural shell in this surgery.
The outlook for empyema with prompt treatment is suitable. Long-term damage to the lungs is rare. You should finish your prescribed antibiotics and have a follow-up chest X-ray. Your doctor can make sure that your pleura has adequately healed.
However, in people with other conditions that compromise the immune system, empyema can have a death rate of up to 40 percent.