Pleural effusion (exudate)

The most common causes of exudates include: (1)

• bacterial pneumonia
  • around 57% of patients with pneumonia will develop pleural fluid
• malignancy
  • the incidence in the US is estimated to be approximately 200,000 new cases each year (2)

The causes of an exudative pleural effusion may be classified as:

• infective
• inflammatory
• malignant
• drug-induced
• miscellaneous

Reference:

1. Roberts ME, Rahman NM, Maskell NA, et al. British Thoracic Society guideline for pleural disease. Thorax. 2023 Jul;78(suppl 3):s1-42.
2. Light RW. Pleural effusions. Med Clin North Am. 2011 Sep 25;95(6):1055-70.