Dfn: It is an inflammatory response to embolic fat macroglobules passing into the small vessels of the lungs & other organs producing endothelial damage which results into respiratory complications, cerebral dysfunction & petechial rashes.
Pathophysiology: 2 Theories-
- Mechanical Theory: Initial Symptoms, by mechanical occlusion of multiple blood vessels with fat globules (Triglyceride particles occlude the microvessels of lungs & other tissues)
- Biochemical Theory: Late Presentation, a result of hydrolysis of fat (by Pneumocyte Lipases) into more irritating/inflammatory toxic ‘free fatty acids‘ which migrate to other organs & tissues (Systemic circulation).
- Fractures- long bone fractures; Pelvic fractures; Polytrauma
- Orthopaedic Procedures
- Massive Soft tissue Injury
- Severe Burns
- Bone Marrow Biopsy
- Bone marrow harvesting & transplant
- Non-traumatic causes-
-Sickle Cell Disease
-Bone tumour Lysis
-Prolonged Corticosteroid Therapy
-Cyclosporine A solvent
- Pulmonary Embolism
- Head Injury
- Diabetic Coma
- Respiratory Insufficiency
- Cerebral Involvement
- Petechial Rashes
- Pyrexia (>39.40C)
- Tachycardia (>120/min)
- Retinal Changes
- Renal Changes- oliguria, anuria
- Hepatic Changes(Jaundice)
LABORATORY FEATURES (L):
- Fat Macroglobulinemia
- Anaemia (decreased Haematocrit)
- Increased ESR
- Cytological Examination of Urine, Blood, Sputum, BAL (bronchoalveolar lavage)- detect Fat globules.
- Chest Xray- “Snow Storm Appearance ” (B/L Fluffy appearance)
- Blood Gas Analysis- paO2 <60mm Hg
- Decreased Hematocrit
- Increased Lipase
- Brain MRI- foci of vasogenic oedema in a random (i.e. embolic) distribution; A “starfield” pattern may be seen on DW imaging.
Sevitt Classification of FES (Fat Embolism Syndrome)- 3 types
- Subclinical FES:
-Fat emboli present in blood & Lungs,
-No clinical signs/symptoms
- Non-Fulminant FES:
- Fulminant FES:
-develops within hours,
-Altered Mental status.
FES vs CEREBRAL INJURY :
MANAGEMENT: Supportive & Symptomatic
- Ensuring good Arterial Oxygenation.
- High flow O2 to be given.
- Restriction of fluid intake + Use of Diuretics- minimize fluid accumulation in lungs.
- Volume resuscitation with Albumin & Balanced Electrolyte Solution – Albumin: restores blood volume; binds ‘free fatty acids’ & decreases the extent of lung injury.
- Mechanical Ventilation & PEEP( Post End Expiratory Pressure).