biochemical theory
Last reviewed 01/2018
The biochemical theory can be subdivided into toxic and obstructive categories:
The toxic theory states that free fatty acids (FFA's) released at the time of trauma (possibly as a result of the action of catecholamines) or by breakdown of fat in the lung affect pneumocytes directly causing adult respiratory distress syndrome (ARDS).
The obstructive theory proposes that chemical mediators released at the site of a fracture affect the solubility of lipids leading to coalescence and subsequent embolisation. One study has found a difference in the cholesterol content of fat emboli compared to marrow fat - a finding consistent with this hypothesis. This study however, has not been confirmed.