[Fat embolism and fracture, a review of the literature]

Abstract

The reasons of fat embolism as well as the following fat embolism syndrome are most likely long bone fractures, especially if the femur is participated. On the other hand there are cases, where a severe concussion of the entire body caused fat embolism. But it is also supposed, that intramedullary reaming as well as the insertion of knee- and hip-prostheses could be a releasing factor, because the applicated pressure on the medullary canal can cause a fat release in the systemic blood system. The morbidity depends on age and fracture, which is on fractures between 0.9 and 2%. The most affected group are people between 18 and 28 years of age. The fat embolism is manifesting at 46-60% of the patients in the first 24 hours and over 90% of the patients are affected in the first three days. If you look at the metabolic changes, you will find shortly after the fracturing process a rapid increase of free fatty acids (FFA), as well as an increase of the plasmatic enzyme levels (lipase, GPT, GOT, GLDH, LDH, etc.), catecholamines and glucocorticoids. In order to discuss the pathogenesis in a fairly complete way, you have to take different theories into consideration, because several parallel running processes--which are influencing each other--are leading to the syndrome. Infloating theory: Proceeding on the assumption that contents of the bone marrow are floating out of the fracture gap into the venous system and are leading to fat embolism in the lungs. Lipase theory: You can diagnose in 50-70% of the fracture patients an increase of the lipase level, which is correlating with the manifestation of the fat embolism. The lipase releases fat from the body depositories in addition to the fat, who is coming out of the fracture gap. Shock and coagulation theory: During shock the microcirculation is decelerated, the blood viscosity is increased and the suspension stability of the cellular blood components is decreased, which is leading to the sludging phenomenon. So the capillaries of the lungs and the brain are a kind of sludge filter of the blood, that is changed in its suspensions stability. Free fatty acids theory: Primary existing capillary defects are reasonable caused by free fatty acids (FFA). They are hydrolyzed of the neutral fats and are histotoxic for the walls of the blood vessels.(ABSTRACT TRUNCATED AT 400 WORDS)