Empyema is a collection of pus in the space between the lung and the inside of the chest wall (pleural space).

Empyema is caused by an infection that spreads from the lung. It leads to a buildup of pus in the pleural space.

There can be a pint or more of infected fluid. This fluid puts pressure on the lungs.

Risk factors include:

• Bacterial pneumonia
• Lung abscess
• Thoracic surgery
• Trauma or injury to the chest

In rare cases, empyema can occur when a needle is inserted through the chest wall to draw off fluid in the pleural space (thoracentesis)

• Chest pain, which worsens when you breathe in deeply (inspiration)
• Dry cough
• Excessive sweating, especially night sweats
• Fever and chills
• General discomfort, uneasiness, or ill feeling (malaise)
• Shortness of breath
• Unintentional weight loss

The health care provider may note decreased breath sounds or a friction rub when listening to the chest with a stethoscope (auscultation).

Tests may include the following:

• Chest x-ray
• CT scan of chest
• Pleural fluid gram stain and culture
• Thoracentesis

The goal of treatment is to cure the infection and remove the collection of pus from the lung. Antibiotics are prescribed to control the infection.

The health care provider will place a chest tube to completely drain the pus. A surgeon may need to perform a procedure to peel away the lining of the lung (decortication) if the lung does not expand properly.

When empyema complicates pneumonia, the risk of permanent lung damage and death goes up. Patients will need long-term treatment with antibiotics and drainage. However, most people fully recover from empyema.

• Pleural thickening
• Reduced lung function

Call your health care provider if you develop symptoms of empyema.

Prompt and effective treatment of lung infections may prevent some cases of empyema.

Celli BR. Diseases of the diaphragm, chest wall, pleura, and mediastinum. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 100.

Mason RJ, Broaddus VC, Murray JF, Nadel JA. Pleural effusion. In: Mason RJ, Broaddus VC, Murray JF, Nadel JA, eds. Murray and Nadel's Textbook of Respiratory Medicine. 4th ed. Philadelphia, Pa: Saunders Elsevier; 2005:chap 68.