Cerebral fat embolism

Case contributed by Dr James Harvey

Presentation

Brought to ED via ambulance following fall from height.

Patient Data

Age: 20 years
Gender: Male

CT scout

X-ray

CT scout demonstrates a transverse fractures of the midshaft of the right humerus with significant bony separation and medial angulation of the distal fracture fragment.

Transverse fractures of the both femurs.

Initial CT head

CT

There is a right sided scalp laceration and hematoma which has been stapled. No skull fracture.

Small subdural hemorrhage within the posterior falx and the left tentorium cerebelli.

Grey-white differentiation is preserved.

Trauma x-ray series

X-ray

Chest: ETT in situ, projected close to the carina. Gastric tube side hole within the stomach.
No displaced rib fracture or pneumothorax.

Right shoulder: transverse fracture through the midshaft right humerus. The distal humerus is not included in the fim.

Right femur: plaster cast in situ. Transverse fracture through the midshaft of the femur.

Right tibia/fibula: tibial plateau fracture with depression and lateral angulation of the lateral tibial plateau. Gas within the subcutaneous tissue indicates an open fracture.

CT head - day 2 of admission

CT

CT head was performed following an emergency call for new confusion and reduced level of consciousness.

There is new heterogeneous appearance of periventricular white matter.

The small left tentorium cerebelli SDH has reduced in size and radiodensity.

MRI brain

MRI
  • Non-confluent T2 and FLAIR high signal within the supratentorial and infratentorial brain with a predominately periventricular distribution
  • Innumerable tiny foci of susceptibility artefact on SWI with involvement of the corpus callosum and grey-white matter junction.
  • Extensive associated periventricular diffusion restriction.
  • No significant mass effect.

Case Discussion

DWI 'starfield pattern' seen in this case refers to multiple bright foci of diffusion restriction on a dark background.

The timing of deterioration in this case is typical of fat embolism syndrome, with patients usually becoming symptomatic 24-72 hours after injury.

The main differential for cerebral fat embolism in a trauma patient will be diffuse axonal injury (DAI). In this case, the innumerable tiny foci of susceptibility artefact and diffusion restriction in a patient with four long bone fractures is highly likely to reflect fat embolism.

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