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Fat embolism syndrome

Gerald L Weinhouse, MD
Section Editor
Polly E Parsons, MD
Deputy Editor
Geraldine Finlay, MD


The fat embolism syndrome (FES) remains a diagnostic challenge for clinicians, despite having been initially described in 1873 [1]. Among the reasons that FES is difficult to diagnose is that it can complicate widely disparate clinical conditions and may vary in severity. Management is supportive, with an estimated mortality rate of 5 to 15 percent [2].

The causes, clinical presentation, pathogenesis, diagnosis, treatment, prevention, and outcomes of FES are reviewed here. Other forms of pulmonary embolism are discussed separately. (See "Overview of acute pulmonary embolism in adults" and "Amniotic fluid embolism syndrome" and "Pulmonary tumor embolism and lymphangitic carcinomatosis in adults: Diagnostic evaluation and management" and "Air embolism".)


Fat embolism syndrome (FES) may complicate a wide variety of clinical conditions (table 1). It is most commonly associated with long bone and pelvic fractures, and is more frequent in closed fractures than open fractures. Patients with a single long bone fracture have a 1 to 3 percent chance of developing FES. This increases with the number of fractures. As an example, FES has been noted in up to 33 percent of patients with bilateral femoral fractures [3]. At autopsy, compared to non-trauma patients, a higher proportion of trauma patients have fat embolism (82 versus 63 percent) [4]. In addition, over 85 percent of all patients who had received cardiopulmonary resuscitation had evidence of fat embolism [4].


Fat emboli may be the result of fat globules entering the bloodstream through tissue (usually bone marrow or adipose tissue) that has been disrupted by trauma or, alternatively, via production of the toxic intermediaries of plasma-derived fat (eg, chylomicrons or infused lipids).

"Mechanical" fat embolism — The supposition that fat from disrupted bone marrow or adipose tissue enters torn venules following trauma originated in the early twentieth century [5]. It presumes that fractures of marrow-containing bone have the highest incidence of fat embolism syndrome (FES) and cause the largest volume of fat emboli because the disrupted venules in the marrow are tethered open by their osseous attachments, allowing the marrow contents to easily enter the venous circulation. The notion is supported by the observation that "echogenic material" passes through the right heart during orthopedic and spinal surgery [6,7].


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Literature review current through: Sep 2016. | This topic last updated: Jan 6, 2016.
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