Case Presentation: A 62-year-old woman with a medical history significant for seizure disorder presented with a right tibia fracture following a mechanical fall. She underwent open reduction and internal fixation of the right tibia and was extubated without difficulty following surgery. The following day, she became febrile and hypoxemic, requiring an escalating amount of oxygen to maintain an acceptable oxygen saturation. Chest radiography revealed new bilateral diffuse infiltrates. Following transfer from the medial floor to the intensive care unit, she failed high flow nasal oxygen and was subsequently intubated and mechanically ventilated. Bronchoscopy with bronchoalveolar lavage was performed, and empiric coverage with vancomycin and piperacillin-tazobactam was initiated. A comprehensive infectious work-up, including cultures of blood and bronchial washings, a respiratory viral panel, and investigations for Streptococcus, Legionella, Mycoplasma, and Chlamydia were all negative.  Her PaO2/FiO2 ratio was consistent with severe acute respiratory distress syndrome (ARDS), and despite low tidal volume ventilation, a fluid conservative strategy, and PEEP titration, she required paralysis and ventilation in the prone position. A CT scan of the chest was negative for pulmonary embolism but revealed diffuse bilateral ground glass opacities with thickened interlobular septa, consistent with a diagnosis of fat embolism syndrome.  She was managed conservatively with diuresis, and was ultimately able to be placed in the supine position and extubated. Following a 10-day stay in the ICU, she was ultimately transferred back to the medical floor and discharged to a skilled nursing facility on hospital day 18. 

Discussion: Fat embolism syndrome (FES) is classically described by Gurd’s triad – respiratory compromise, neurological symptoms, and petechial rash – though only 20-50% of cases manifest with petechiae. The pathophysiology of respiratory failure in FES includes mechanical embolism of fat globules to the pulmonary circulation and a subsequent systemic inflammatory response mediated by several pro-inflammatory cytokines. FES secondary to a long bone fracture is generally uncommon, occurring in 1-5% of long bone fractures; isolated tibia or fibula fractures have a FES incidence of 0.3%. Respiratory complications, ranging from mild hypoxemia to ARDS, have been noted in up to 75% of cases with FES. Treatment is largely supportive, and early operative intervention is modestly successful in reducing its occurrence.

Conclusions: As hospitalists are increasingly involved in the co-management of orthopedic surgery patients, recognition of FES as a cause of peri-operative respiratory failure is important. FES must quickly be distinguished from more common complications causing respiratory failure in hospitalized patients, including healthcare-acquired pneumonia and pulmonary embolism.