Fat embolism
Encyclopedia
A fat embolism is a type of embolism
that is often caused by physical trauma
such as fracture of long bones, soft tissue trauma and burns.
Fat embolism syndrome (FES) is distinct from the presence of fat emboli. Symptoms usually occur 1-3 days after a traumatic injury and are predominantly pulmonary (shortness of breath, hypoxemia
), neurological (agitation, delirium, or coma), dermatological (petechial rash
), and haematological (anaemia, low platelets). The syndrome manifests more frequently in closed fractures of the pelvis or long bones. The petechial rash, which usually resolves in 5-7 days is said to be pathognomonic
for the syndrome, but only occurs in 20-50% of cases.
Fat emboli occur in almost 90% of all patients with severe injuries to bones, although only 10% of these are symptomatic. The risk of fat embolism syndrome is thought to be reduced by early immobilization of fractures and especially by early operative correction. There is also some evidence that steroid prophylaxis of high-risk patients reduces the incidence. The mortality rate of fat-embolism syndrome is approximately 10-20%.
Maintenance of intravascular volume is important because shock can exacerbate the lung injury caused by FES. Albumin
has been recommended for volume resuscitation in addition to balanced electrolyte solution, because it not only restores blood volume but also binds fatty acids, and may decrease the extent of lung injury.
Embolism
In medicine, an embolism is the event of lodging of an embolus into a narrow capillary vessel of an arterial bed which causes a blockage in a distant part of the body.Embolization is...
that is often caused by physical trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
such as fracture of long bones, soft tissue trauma and burns.
Presentation
Unlike emboli that arise from thrombi (blood clots), fat emboli are small and multiple, and thus have widespread effects.Fat embolism syndrome (FES) is distinct from the presence of fat emboli. Symptoms usually occur 1-3 days after a traumatic injury and are predominantly pulmonary (shortness of breath, hypoxemia
Hypoxemia
Hypoxemia is generally defined as decreased partial pressure of oxygen in blood, sometimes specifically as less than or causing hemoglobin oxygen saturation of less than 90%.-Distinction from anemia and hypoxia:...
), neurological (agitation, delirium, or coma), dermatological (petechial rash
Petechia
A petechia is a small red or purple spot on the body, caused by a minor hemorrhage ."Petechiae" refers to one of the three major classes of purpuric skin conditions. Purpuric eruptions are classified by size into three broad categories...
), and haematological (anaemia, low platelets). The syndrome manifests more frequently in closed fractures of the pelvis or long bones. The petechial rash, which usually resolves in 5-7 days is said to be pathognomonic
Pathognomonic
Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...
for the syndrome, but only occurs in 20-50% of cases.
Fat emboli occur in almost 90% of all patients with severe injuries to bones, although only 10% of these are symptomatic. The risk of fat embolism syndrome is thought to be reduced by early immobilization of fractures and especially by early operative correction. There is also some evidence that steroid prophylaxis of high-risk patients reduces the incidence. The mortality rate of fat-embolism syndrome is approximately 10-20%.
Pathogenesis
The pathogenesis occurs due to both mechanical obstruction and biochemical injury. The microemboli cause pulmonary and cerebral microvasculature occlusion. It is aggravated by local platelet and erythrocyte aggregation. The release of free fatty acids from the fat globules causes local toxic injury to endothelium. The vascular damage is aggravated by platelet activation and recruitment of granulocytes.Treatment
The most effective prophylactic measure is to reduce long bone fractures as soon as possible after the injury.Maintenance of intravascular volume is important because shock can exacerbate the lung injury caused by FES. Albumin
Albumin
Albumin refers generally to any protein that is water soluble, which is moderately soluble in concentrated salt solutions, and experiences heat denaturation. They are commonly found in blood plasma, and are unique to other blood proteins in that they are not glycosylated...
has been recommended for volume resuscitation in addition to balanced electrolyte solution, because it not only restores blood volume but also binds fatty acids, and may decrease the extent of lung injury.
See also
- Air embolismAir embolismAn air embolism, or more generally gas embolism, is a pathological condition caused by gas bubbles in a vascular system. The most common context is a human body, in which case it refers to gas bubbles in the bloodstream...
- Cholesterol embolismCholesterol embolismCholesterol embolism occurs when cholesterol is released, usually from an atherosclerotic plaque, and travels along with the bloodsteam to other places in the body, where it obstructs blood vessels...
- Pulmonary embolismPulmonary embolismPulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
- CT pulmonary angiogramCT pulmonary angiogramCT pulmonary angiogram is a medical diagnostic test that employs computed tomography to obtain an image of the pulmonary arteries. Its main use is to diagnose pulmonary embolism...
External links
- Fat Embolism MRI Brain Injury from Fat Embolism