Case of the Month February 2015, Page 3

Fat Emboli

  • Generally caused by the venous embolization of fat from long bone fractures, orthopedic surgery, venous-arterial shunts or cardiac surgery sending emboli into the systemic circulation embolizing the brain or kidneys most commonly.
  • Fat lobules are transferred from the venous system to the arterial system either through direct shunting or by passing directly through pulmonary capillaries.
  • When fat emboli enter the brain neurological symptoms are nonspecific and highly variable ranging from headache and confusion to coma or seizures.
  • Fat Embolism Syndrome manifests as the triad of pulmonary, central nervous and cutaneous symptoms (e.g. Hypoxia, Altered mental status and petechial rash.)
  • Radiographic findings are most specific using MR diffusion weighted imaging.
  • Multiple scattered foci of diffusion restriction within the gray and/or white (star field pattern) consistent with diffuse acute infarctions is the earliest and most specific finding. The quantity of focal diffusion abnormalities correlates with GCS score.
  • T2 findings may present later with multiple scattered foci of increased signal intensity.
  • Non-enhanced CT can demonstrate the “hyPOdense MCA sign” due to fat within the MCA.
  • There is a wide range of commonly affected territories: deep and periventricular white matter, deep gray nuclei, typical vascular territory as well as "watershed" territories.

 

Works Cited

  • Parizel PM et al: Early diagnosis of cerebral fat embolism syndrome by diffusion-weighted MRI (starfield pattern). Stroke. 32(12):2942-4, 2001
  • Karen L. Salzman, MD. Cerebral Infarction, Fat Emboli. Retrieved from https://app.statdx.com/document/cerebral-infarction-fat-emboli/1e545393-1f5a-4246-bed2-5f9197e4b258

 

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