Discussion Author: Laura N Modzelewski
Fat embolism syndrome is generally associated with displaced long bone fractures of the lower extremities. I has also been reported as a complication of surgical procedures, including liposuction. Fat emboli may reach the brain through a right-to-left cardiac shunt or through an intact pulmonary circulation. Fat emboli are deformable and can penetrate capillary beds intact or may be broken up into smaller fat globules.
Clinical presentation may be delayed hours and even days after injury, such as long bone fracture. The clinical characteristics of fat embolism syndrome include respiratory insufficiency, neurological symptoms and petechial skin rash (predominant axillary pattern).
Neurologic symptoms vary but usually initially manifest as an agitated delirium which may advance to seizures, coma, stupor. In many cases neurologic function may be recovered in days to months.
Cerebral fat emboli activate chemical mediators that breakdown the capillary endothelium and blood-brain-barrier causing focal vasogenic edema without infarction or hemorrhage in mild cases. However, in severe cases infarction and hemorrhage are possible. The likelihood of infarction and hemorrhage seems to depend on the size of the fat globules which, in turn, depends on the presence or absence of a R-L shunt and the overall embolism load of fat.
Lesions may be very small or punctate and present in the deep white-matter - in contrast to the cortical-subcortical location pattern more commonly seen with particulate embolization or clot showers.
Cerebral CT may be negative; and, MR imaging is the most sensitive technique to evaluate for cerebral fat embolism. Long TR sequences show foci of vasogenic edema in the white matter - subcortical, deep and periventricular. Gradient echo imaging can help to determine the presence of concomitant focal hemorrhage - if present.
Diffusion weighted imaging can help to determine the presence of concomitant embolic cytotoxic edema and/or infarction. Finally, post GAD T1W imaging can help to demonstrate breakdown of the blood brain barrier.
Other imaging differential diagnoses include common white matter etiologies in this age group i.e. multiple sclerosis, acute disseminated encephalomyelitis (ADEM). These are less likely because of the temporal relationship of the symptoms with the injury. In the setting of trauma, diffuse axonal injury (DAI) should be added to the differential diagnosis
Read more - - LINK -
- LINK -
MR of cerebral fat embolism may cause the "starfield pattern" of hyperintensities - seen on T2W and DWI - in the mid to deep white matter of both cerebral hemispheres.
PMID: 11740000 - - LINK -
PMID: 12533333 - - LINK -
Topic Details: Fat Embolism, Brain :: :: Search for other Topics with Fat Embolism, Brain
Highlight this =>[ Fat Embolism, Brain ]<= for a Popup Search Tool