- Fat Emboli are a subtype of emboli composed of bone marrow particles released into the circulation following traumatic fracture, especially of long bones. Fat Emboli derive their namesake because long bones possess a sizable amount of adipose tissue and thus release particles largely composed of fat.
- The characteristic syndrome following fracture of long bones is known as "Fat Emboli Syndrome" (FES). In the majority of patients long bone fracture does not lead to clinically apparent FES. However, when FES does occur it is characterized by pulmonary, neurologic, and cutaneous symptoms which manifest 1-3 days post-fracture.
- Pulmonary Symptoms:
- Pulmonary symptoms dominate FES and are characterized by dyspnea and hypoxemia due to development of ARDS. Pulmonary symptoms are a result of fat emboli depositing in the pulmonary circulation and possibly releasing toxic fatty acids which damage the alveolar membrane.
- Neurologic Symptoms:
- The neurologic symptoms of FES are characterized by confusion, somnolence, or coma. These are likely due to deposition of fat emboli in the cerebral circulation which often results in diffuse cerebral petechiae.
- Cutaneous Symptoms:
- Cutaneous symptoms are characterized by the diffuse development of [petechiae. This is likely due to the thrombocytopenia that develops during FES which is a result of platelet trapping by the fat emboli. Anemia develops in some with FES likely through trapping and shredding of erythrocytes by vascular fat emboli.