What type of effusion is likely caused by infections or malignancies?

Exudative effusion is characterized by the presence of high levels of protein and other cellular content in the pleural or peritoneal fluid, which typically arises from inflammation or injury to the pleura or peritoneum. Infections and malignancies lead to increased permeability of blood vessels, allowing proteins and cells to pass into the effusion, which distinguishes exudative effusions from transudative types that usually result from systemic factors like changes in hydrostatic or oncotic pressure without significant local inflammation.

In cases of infections, such as pneumonia, or malignancies, the localized inflammatory response can cause a collection of fluid that may contain pus, cancer cells, or inflammatory cells, making it an exudate. The analysis of pleural fluid or ascitic fluid can help differentiate between exudative and transudative effusions based on criteria like the Light's criteria, which considers protein levels and the presence of LDH.

The other types of effusion mentioned differ in cause and composition. Transudative effusions typically arise from systemic conditions without local inflammation, such as heart failure or cirrhosis. Cytogenic effusion isn't a standard term in pathology and might have been misrepresented. Hydrostatic effusion is not a recognized classification in