An animal model for aseptic necrosis after intramuscular injections.

Ten drugs or vaccines commonly given to patients by intramuscular injection were injected into the femoral artery of normal young anaesthetized pigs, in order to establish an animal model for macroscopically identifiable aseptic tissue necrosis (Nicolau syndrome). Despite the wide range of constituents and chemical groupings in the drugs which had caused Nicolau syndrome in patients, when injected into the pigs a typical pattern of reactions could be observed for many of them, as follows: the leg contracted rapidly, the skin area supplied by this artery initially became pale and then bluish-red with an irregular reticular appearance before finally tissue necrosis developed. These reactions are comparable to the symptoms of Nicolau syndrome in man. However, no reactions were seen when drugs or vaccines which have not been known to cause aseptic necrosis in man, e.g. tetanus toxoid, influenza vaccine or triamcinolon, were injected i.a.