Fat embolism syndrome

Background

• Caused by fat globules in pulmonary microcirculation
• Fat is prothrombotic and pro-inflammatory
• Commonly associated with orthopedic fractures, especially long bone fractures of lower extremities (eg. femur)
• Occurance in Men > women, highest rates: ages 10-40 y/o
• Typically occurs 12-72 hrs after initial insult

Clinical Features

• Multi-organ system dysfunction
• Classic triad: hypoxemia, neurological abnormalities and petechiae
• Neuro findings included: focal deficits, altered mental status, coma
• Thrombocytopenia and anemia common
• Can progress to DIC
• Fulminant cases: RV dysfunction, biventricular failure, ARDS, shock, death
• Other etiologies (uncommon): pancreatitis, sickle cell crisis, alcoholic liver ds, bone marrow harvest/transplant/liposuction

Differential Diagnosis

• Pulmonary embolism
• ARDS
• Pulmonary edema
• Alveolar hemorrhage
• Other causes of [[hypoxemia]
• Other causes of shock

Evaluation

Clinical diagnosis, no gold standard

Gurd's Criteria

• Most frequently cited diagnostic criteria
• Need 1 major, 4 minor

Major

• Petechial rash
• Resp symptoms w XR changes
• CNS signs unrelated to another condition

Minor

• Tachycardia
• Pyrexia
• retinal changes (fat or petechiae)
• renal abnormalities (oliguria, anuria or lipiduria)
• thrombocytopenia
• acute anemia
• elevated ESR
• fat globules in sputum

• Chest Xray/CT scan chest
  • Bilateral patchy infiltrates
• MRI brain: star-field pattern of diffuse, punctate, hyperintense lesions on DWI
• Bronchoalveolar lavage
  • 30% of alveolar cells staining for fat strongly asso w diagnosis

Management

Acute Care

• Supportive care
• Heparin and steroids have not shown improvement
• Supplemental O2, mechanical ventilation if needed
• Frequent neurochecks, consider ICP monitoring
• Vasopressors as needed
• Refractory hypotension/shock: consider ECMO

Prevention

• Decreased incidence with orthopedic repair within 24h
• Consider prophylactic corticosteroids in patients with long bone fractures
  • decreased hypoxemia, no difference in mortality

Disposition

• ICU

See Also

• Pulmonary embolism
• Hypoxemia

References

Authors

Claire