The fibrinolytic enzyme system after trauma and in patients with fat embolism.

The pathogenesis of fat embolism, a common complication of fractures of the long bones of the lower limbs, is not delineated. Any explanation must take account of the recognised association of intravascular fibrin deposits with fat embolism. The fibrinolytic enzyme system may function to remove unwanted fibrin in the body. It consists basically of an inactive globulin, plasminogen, which is converted to the protease plasmin by agents present in tissues and circulating blood termed collectively plasminogen activators. Plasmin is capable of hydrolysing fibrin to soluble polypeptides known as fibrin degradation products (Fig. 1).