Fat embolism syndrome
A fat embolism (FE) is a piece of intravascular fat that lodges within a blood vessel and causes a blockage of blood flow.
Most often seen after a long bone fracture (usually femoral, but may include clavicular, tibial, and even isolated skull fracture). Although almost all patients have pulmonary fat emboli at autopsy, the syndrome is usually mild or subclinical, only ≈ 10–20% of cases are severe, and the fulminant form leading to multiple organ failure is rare.
Clinical findings usually appear within 12–72 hrs of injury, and do not always include the complete classic clinical triad of:
● acute respiratory failure (including hypoxemia, tachypnea, dyspnea) with diffuse pulmonary infiltrates (usually seen as bilateral flu y infiltrates). May be the only manifestation of fat emboli in up to 75%of cases
● global neurologic dysfunction: may include confusion (PaO2 usually not low enough to account for these changes 1) ), lethargy, seizures
● petechial rash: seen ≈ 24–72 hrs after the fracture, usually over thorax
Other possible findings include:
● pyrexia
● retinal fat emboli
There is no specific test for fat embolism syndrome (FES). The following have been proposed, but have poor sensitivity and specificity: fat globules in the urine (positive in ≈ one–third 2)) and serum, serum lipase activity. In cases of unexplained neurologic or pulmonary abnormalities, it may be possible to diagnose FES if on bronchoalveolar lavage 3)
● > 5 % of cells in the washings staining for neutral fat with red oil 0. Nonspecific tests include ABG (findings: hypoxemia, hypocarbia from hyperventilation, respiratory alkalosis).