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