Which laboratory finding indicates the presence of fat embolism syndrome (FES)?

In the context of fat embolism syndrome (FES), a decreased red blood cell (RBC) count is a notable laboratory finding. FES typically occurs after a fracture or trauma when fat globules from the bone marrow enter the bloodstream. These fat globules can cause mechanical obstruction in the microvasculature, leading to various systemic effects, including respiratory distress, neurological symptoms, and hematological changes.

When fat globules enter the circulation, they can lead to a dilutional effect on red blood cells. This is especially true if the patient develops anemia due to the trauma or surgery associated with the fracture. The body’s response to such an event can often result in a decreased RBC count, as the injury leads to both potential blood loss and a shift in the body’s environment due to the introduction of fat globules.

Understanding this relationship helps in recognizing how FES can manifest not only through systemic symptoms but also through specific changes in laboratory values. The presence of fat globules in the blood may also impair the ability to form adequate blood cells and can lead to other conditions contributing to anemia. This reflects the systemic impact of fat infiltration and subsequent physiological changes triggered by the syndrome.

In contrast, increased RBC counts, elevated serum calcium levels,