Thoracic empyema

Thoracic empyema or pleural empyema refers to accumulation of pus in the pleural cavity. The most common bacteria involved are streptococci and staphylococci. Mycobacteria are a rare cause.

Development of thoracic empyema is a cause of treatment failure for pneumonia, and it should be considered in those cases where patients don’t get better on antibiotic treatment.

Etiology

Thoracic empyema can be primary (idiopathic) or secondary to:

• Pneumonia (most common)
• Infected haemothorax or hydrothorax
• Ruptured lung abscess
• Thoracic surgery

When secondary to pneumonia it’s sometimes called a parapneumonic effusion.

Clinical features

The clinical features of thoracic empyema are similar to those of pneumonia, with fever, cough, pleuritic chest pain, dyspnoea, sputum, etc. Physical examination may reveal findings of pleural fluid, like dullness on percussion, decreased breathing sounds, and decreased fremitus.

Thoracic empyema develops in stages, from a simple effusion to empyema to chronic organisation of the fluid.

Diagnosis and evaluation

Thoracic empyema is usually suspected when an x-ray is performed on a patient with suspected or known pneumonia. From there, ultrasound or CT may be used to visualise the pleural fluid and to guide thoracocentesis. Only thoracocentesis and analysis of the fluid can prove that the fluid is pus. The fluid should be cultured for bacteria.

Treatment

Treatment involves drainage and antibiotics. Drain may be one-time (thoracocentesis) or continuous with a tube thoracostomy.