fat embolism, a circulatory condition characterized by the blocking of an artery by a plug of fat. The plug enters the circulatory system after the fracture of a long bone or, less commonly, after traumatic injury to adipose tissue or to a fatty liver. Fat embolism usually occurs suddenly 12 to 36 hours after an injury and is characterized by symptoms related to the site occluded, such as severe chest pain, pallor, dyspnea, tachycardia, delirium, prostration, and in some cases coma. Anemia and thrombocytopenia are common. Systemic fat embolism may occur after extensive trauma, since lipid metabolism is altered by the injury and free fatty acids are released, resulting in vasculitis with obstruction of many small pulmonary and cerebral arteries. Classic signs of systemic fat embolism are petechial hemorrhages on the neck, shoulders, axillae, and conjunctivae that appear 2 or 3 days after the injury. Radiographic findings include patchy diffuse opacities throughout the lungs. There is no specific therapy for systemic fat embolism. The patient is placed in a high Fowler’s position and given oxygen, corticosteroids, blood transfusion, respiratory assistance, or other supportive care as needed. Compare air embolism, gas embolism.
