Clinical features
Most recent studies show that clinical signs and symptoms occur only in 1-10% of patients with fractures. Clinical presentation includes a wide range of symptoms and thus severity. A high level of suspicion should be taken into account when a patient presents with the classic triade of hypoxia, confusion/neurological abnormalities and petechial rash.3 The clinical manifestations are preceded by an asymptomatic latent period of about 12–48h, but it can occur intraoperatively or as late as two weeks after the inciting event. Embolization begins rather slowly and attains a maximum in about 48hours. Most commonly the onset is gradual but sometimes it can be fulminant with pulmonary and systemic embolization, right ventricular heart failure and collapse.3
Most commonly and primarily involved is the respiratory system. Up to 75% of patients with FES present with some degree of respiratory failure, ranging from nearly asymptomatic hypoxemia to pulmonary distress requiring ventilatory support.6 The most fulminant and lethal form of FES presents as acute cor pulmonale with respiratory failure within a few hours of injury. Usually, the lung recovers by the third day. Acute right heart failure is seen if the embolism occludes 80% of the pulmonary capillary meshwork.5
The central nervous system is the second most commonly involved system, usually in combination with pulmonary disturbances. The symptoms are highly variable, usually nonspecific and ranging from a simple headache to rigidity, disorientation, confusion, convulsion, stupor, and coma. These symptoms are usually non lateralizing, tend not to respond to O2 therapy but are transient and fully reversible.6,8Some propose that smaller globules may traverse the pulmonary microvasculature and reach the systemic circulation, leading to the common neurological manifestation of FES.6,8
In 50%–60% of patients a petechial non-blanching rash is present on the upper anterior area of the body, axillae, neck, upper arms, and shoulders.6 It may also be present in the oral mucous membranes and conjunctivae. It has never been described on the back. The rash results from occlusion of the dermal capillaries by fat causing increased capillary fragility. It tends to be transient and disappears after 24 hours.5,6
An invariable cardiovascular sign of FES is tachycardia, but this does not often help with the diagnosis of FES since there are many causes of tachycardia in the trauma patient.
Retinal manifestations of FES are present in about 50% of patients, most of these findings disappear within a few weeks. They consist of cotton-wool exudates and small hemorrhages along the vessels and macula.6,8
Other less common and nonspecific manifestations are anemia, fever, myocardial depression or hypotension.6