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FAT EMBOLISM SYNDROME(FES)

 

INTRODUCTION

• Fat embolism – obstruction by fat embolus, occurring especially after fractures of large bones.

• Fat embolism syndrome - a serious manifestation of respiratory, dermatological and neurological symptoms.

• Most commonly is associated with long bone and pelvic fractures. long bone fractures (1-20 %)

• More frequent in closed, rather than open fractures.• Typically manifests 24 to 72 hours after the initial insult.

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PATHOPHYSIOLOGYMechanical theory

Large fat droplets released into venous 

system

Physical obstruction of pulmonary and systemic 

vasculature with embolised fat

Biochemical theory

Local hydrolysis of triglyceride

Emboli by pneumocyte lipase

Excessive mobilization of FFA from peripheral adipose tissue by cathecolamine

Toxic pulmonary concentration of FFA

Damage small vessel perfusion

Endothelial damage in pulmonary capillary beds

Ventilation perfusion deficit

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• Present with a classic triad: hypoxemia; neurologic abnormalities; and a petechial rash

• Symptoms: – High temperature– Tachycardia– Shortness of breath– Restlessness– Mild confusion

– Worst cases:• Marked respiratory distress• Restlessness• Coma• Death

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CLINICAL FEATURES

• Signs– Petechiae : on the head, neck, anterior thorax,

subconjunctiva, and axillae.• Result from the occlusion of dermal capillaries by fat

globules, leading to extravasation of erythrocytes.– Hypoxaemia (<8kPa/60 mmHg) is suspicious

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DIAGNOSISGurd‘s Major Criteria Gurd's Minor Criteria

Axillary or subconjuctival petechial occurs transiently (4-6 hours) in 50-60 % of the cases

Tachycardia (> 110 beats per minute)

Hypoxemia (PaO2 <60 mmHg) Pyrexia (temperature > 38.5 ⁰C)Central nervous system depression disproportionate to hypoxemia, and pulmonary edema

Emboli present in retina on funduscopic examination

Fat present in urineFat present in sputumSudden unexplainable drop in hematocrit or platelet values Increasing sedimentation rate

Diagnosis of FES requires at least 1 sign from major criteria and at least 4 signs from the minor criteria

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SCHONFELD’S SCORING

Laboratory • ABG - hypoxia • Thrombocytopenia, anemia, and hypofibrinogenemia

are indicative of FES, but nonspecific.• Urine, blood, sputum examination with Sudan or oil red

O staining detect fat globules• ECG

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INVESTIGATIONS

Imaging • CXR-diffuse bilateral pulmonary infiltrates • Head CT-normal or diffuse white matter petechial hemorrhages• Chest CT

Parenchymal changes consistent with lung contusion, acute lung injury, or ARDS.

Nodular or ground glass opacities in the setting of trauma suggest fat embolism.

• V/Q scan-normal or subsegmental perfusion defects

Procedures • BAL-staining of alveolar macrophages for fat

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INVESTIGATIONS

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• Early immobilization of fractures reduces the incidence of FES.

• Risk is further reduced by operative correction rather than conservative management (ie, traction alone).

• Supportive care is the mainstay of therapy for clinically apparent FES. Maintenance of adequate oxygenation and ventilation Stable hemodynamics Blood products as clinically indicated Hydration Prophylaxis of DVT and stress-related gastrointestinal

bleeding Nutrition

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TREATMENT

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Early stabilization of long bone fractures is recommended to minimize bone marrow embolization into the venous system. Rigid fixation within 24 hours has been shown to make a 5-fold

reduction in the incidence of adult respiratory distress syndrome (ARDS).

Surgical technique, particularly of reaming or nailing the marrow, may help reduce the volume of fat embolization.

Prophylactic placement of inferior vena cava filters may help reduce the volume of fat reaching the heart.

SURGICAL CARE