Severe protein C deficiency and aseptic osteonecrosis of the hip joint: a case report

Homozygous congenital protein C deficiency is accompanied by severe thrombo philia. Thrombotic events can be reduced in number and severity by lifelong oral anticoagulation therapy. A 4-year-old boy was first diagnosed as havi ng severe congenital homozygous protein C deficiency during the neonatal pe riod when purpura fulminans occurred as the first manifestation of thrombos is. From this time he had been treated with phenprocoumon (INR 3.5-4.5). Du ring an infection of the upper respiratory tract he developed signs of a ne w episode of purpura fulminans (INR 2.6). Additional anticoagulation therap y with LMW heparin (Clexane(R)) and protein C concentrate was given while t he oral anticoagulation therapy was continued. On the third day of this epi sode the boy suffered from pain of unknown origin. MRI of the abdomen and o f the pelvis revealed nontraumatic osteonecrosis of the hip joint. After a few weeks of immobilisation no special treatment was necessary. One year la ter he was able to walk with no problem. Conclusion Aseptic osteonecrosis of the hip joint is associated with a vari ety of disorders including vascular thrombosis and haemorrhage. Especially young children and handicapped patients with thrombophilia and pain of unkn own origin are suspected to have thrombosis in atypical regions.