A 30-year-old woman suffers massive trauma in an automobile accident and expires 4 days later of respiratory insufficiency. A horizontal section of the patient's brain at autopsy reveals numerous petechiae scattered throughout the white matter. Which of the following is the most likely explanation for this pathologic finding?

Small emboli, notably those composed of fat or air, occlude capillaries. Fat emboli originating from bone fractures are carried downstream through the cerebral vessels until the caliber of the emboli exceeds that of the blood vessels, at which point they lodge and block blood flow. The distal capillary endothelium becomes hypoxic and permeable, and petechiae develop, most commonly in the white matter. Although sepsis (choice D) sometimes leads to brain petechiae, the patient's condition does not support this conclusion. None of the other choices are characterized by petechiae in the brain.Diagnosis: Fat embolism