Pleural effusions in pulmonary embolism
Pleural effusions in pulmonary embolism are thought to be the fourth commonest cause of pleural effusions.
The pleural fluid is almost always an exudate . The presence of pleural fluid is however not thought to be directly due to infarction .
They usually occupy less than one third of the hemithorax.
Often can be difficult to differentiate from effusions due to other causes, other than for the concurrent presence of emboli on the scan with no other definite underlying pathology. Approximately 20% of cases may show loculations . The affected side may depend on the side of embolic burden (around 85% occur ipsilateral to the emboli ) and the majority tend to be unilateral .