If you fracture one of the long bones of your lower body due to a slip-and-fall or another type of accident, you could be at risk of developing a fat embolism. The long bones in question include those of your hip, thigh and shin. In some circumstances, a piece of fat, called an embolus, can become lodged in one of your blood vessels following a long bone fracture. This can block the flow of blood.

The presence of fat emboli in the bloodstream is not always dangerous. However, at times it can lead to a condition called fat embolism syndrome. FES can occur within 12 to 72 hours after a trauma. It can cause potentially deadly neurological changes, inflammation and multi-organ dysfunction.

Causes

Research has yet to conclusively demonstrate the cause of fat emboli and FES. However, two established scientific facts may be significant: Long bones contain more bone marrow than their smaller counterparts, and bone marrow consists of fatty cells. Building upon these facts, one prominent theory holds that fat emboli form as a result of fat cells from the bone marrow leaking into the bloodstream as a result of the fracture and then clumping together.

Prevalence

While fat emboli are a common occurrence following a fracture, FES does not occur as often. Patients with one fracture of a long bone tend to develop FES approximately 3% to 4% of the time. However, if you have more than one long-bone fracture at the same time, you are at greater risk for FES.

Symptoms

FES can cause shortness of breath and rapid breathing, fever, coma, lethargy, mental confusion and anemia. Bleeding under the skin can cause a pinpoint rash in the areas of the neck, chest and head called a petechial rash.

FES that develops after a long-bone fracture is a medical emergency. However, with prompt medical treatment, you may survive and recover fully.