EM Monthly Quiz: Fighting fat embolism syndrome

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What’s the best step in management?

A 27-year-old male patient is transported to the ED with shortness of breath and hypoxemia.  He was found struggling to breathe at an acute rehab facility, recovering from the fracture depicted here.  His vital signs are HR 109, BP 103/66, RR 22, SpO2 97% (non-rebreather), T 37.1°C (98.8°F).  His respiratory exam reveals crackles in all lung fields.  A chest radiograph is consistent with bilateral pulmonary opacities throughout lung fields.


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What is the next best step in management?

  1. Furosemide
  2. Heparin infusion
  3. Nitroglycerin infusion
  4. Noninvasive positive pressure ventilation
  5. tPA

Correct answer: D. Noninvasive positive pressure ventilation


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This patient has signs and symptoms that are concerning for fat embolism syndrome, noted especially by the bilateral pulmonary opacities concerning for acute respiratory distress syndrome (ARDS). Fat emboli are classically associated with long-bone fractures, or several days following intramedullary nailing.  Emboli can occur anywhere, especially the lungs, liver and brain. Diagnosis can be made by finding fat globules in the urine.  Treatment of fat embolism is generally supportive, and most patients recover without serious sequelae. Treatment of ARDS in the setting of pulmonary fat embolism is the same as in any other circumstance of ARDS, including lung protective ventilation, elevated head of bed, and diuresis as tolerated. Noninvasive positive pressure ventilation (NIPPV) is indicated for ARDS and provides both some stenting of the alveoli that are collapsing and some reduction in preload, which helps with volume status in the lungs. Even though this patient now has an SpO2 of 97%, it is on a non-rebreather, and the ARDS pathophysiology necessitates positive pressure ventilation.

Incorrect answer choices:

Nothing beyond supportive care has shown benefit in fat embolism syndrome. Although tPA (Choice E) and heparin infusion (Choice B) are enticing options, the pathophysiology of fat embolism and thrombus embolism are sufficiently different that the two entities cannot be treated the same. Acute coronary syndrome (for which heparin and tPA can also be indicated) should be considered, and an EKG and troponin level would be reasonable to obtain at his initial presentation, but this would be a very uncommon cause of his symptoms. The utility of the EKG and troponin would be to evaluate for right ventricular strain, and a 2D echocardiogram would also be indicated, also to look for RV strain.

Also on the differential is acute pulmonary embolism, for which heparin would be indicated, is unlikely in this scenario.  Patients who undergo surgery are at higher risk for PE, but this presentation is more consistent with ARDS, which is not a common presenting finding in acute PE.  A patient suffering from a venous thromboembolism in their pulmonary arteries are likely to have clear lungs, without bilateral infiltrates seen on CXR.

Furosemide (Choice A) is not unreasonable in the setting of ARDS, for which evidence supports neutral to hypovolemic fluid status. However, at this point the most urgent next management step is faster-acting NIPPV.


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Finally, nitroglycerin infusion (Choice C) is indicated for acute congestive heart failure, but is not helpful for ARDS or fat embolism syndrome. A clinical scenario of a young, otherwise healthy, patient, with no known cardiac risk factors, such as HOCM or polysubstance abuse, developing new CHF is a very low probability.

References

Menkes JS. Chapter 267. Initial Evaluation and Management of Orthopedic Injuries. In: Tintinalli JE, Stapczynski JS, Ma OJ, et al. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 8th ed. New York: McGraw Hill Professional; 2016.

Shaikh N. Emergency management of fat embolism syndrome. J Emerg Trauma Shock. 2009. 2(1):29-33.

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