Fat embolus syndrome in multitrauma case

Case contributed by Dr Dayu Gai

Presentation

This 20 year old male was involved in a motorbike accident requiring multiple external fixations of his bilateral comminuted lower limb fractures. On day 1 post operation, he had a sudden decline in GCS, with bilateral clonus and hyper-reflexia (lower limbs > upper limbs). An MRI brain was performed.

Patient Data

Age: 20
Gender: Male

Conclusion:

  • The imaging findings are characteristic of those secondary to fat embolism.
    • Extensive bilateral punctate foci of diffusion restriction, seen in both cerebral hemispheres. The most numerous foci are in the deep and periventricular white matter however further foci are seen involving the cortex, grey matter nuclei as well as the brainstem and cerebellar peduncles with only minimal involvement of the cerebellar hemispheres. Faint FLAIR and T2 signal is seen in these regions. No evidence of susceptibility artefact of T1 hyperintensity.
  • Diffuse axonal injury and ischaemia secondary to a hypotensive episode are considered much less likely.

Case Discussion

Fat embolism syndrome (FES) is a phenomenon usually found in trauma patients. It typically occurs post long bone fracture. These include the femur, pelvis and tibia. Pathophysiologically, fat from the marrow of the long bones may flick off and lodge themselves in smaller vessels distally. Usually, these fat emboli lodge in the pulmonary vasculature. This patient had a ventricular septal defect which facilitated the fat emboli bypassing the pulmonary vasculature and travelling arterially into the brain.

Fat embolism syndrome classically presents as a triad of:

  • Respiratory failure - pulmonary embolism
  • Cerebral dysfunction - cerebral embolism
  • Skin petechiae - skin embolism

The clinical manifestations of FES typically occur 24-72 hours post trauma 1. Clinical diagnosis of FES can be made using Gurd and Wilson's major and minor criteria 2. This requires at least one of the major criteria, and at least four minor criteria. They are:
Major Criteria:

  • Petechial Rash
  • Respiratory insufficiency
  • Cerebral involvement

Minor Criteria:

  • Tachycardia
  • Fever
  • Retinal changes
  • Jaundice
  • Renal signs
  • Thrombocytopaenia
  • Anaemia
  • Raised ESR
  • Fat macroglobinaemia

Management of FES is conservative, by ensuring good arterial oxygenation and maintaining intravascular volume (in order to prevent concurrent shock). Medical therapy has largely been found to be ineffective.

Case contributed by A/Prof. Pramit Phal.

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Case information

rID: 31737
Case created: 24th Oct 2014
Last edited: 10th Dec 2015
Inclusion in quiz mode: Included

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