[Decreased Quick percentage, acquired factor X deficiency, hemarthrosis and ecchymosis: amyloidosis].

A 68-year-old woman suffered from spontaneous hemarthrosis of the right elbow joint in april 1994. Cutaneous ekchymoses had been noted since summer 1993. Prothrombin time was prolonged (Quick percentage 40-50%) and was not corrected by prolonged administration of vitamin K. Coagulation studies showed isolated factor X (FX) deficiency without circulating FX inhibitor. This suggested the diagnosis of systemic amyloidosis which was retrospectively confirmed in small bowel biopsy specimens obtained one year before. Bilateral femoral head necrosis and femoral neck fracture due to amyloidosis, necessitated orthopedic surgery. The patient died four weeks postoperatively after several episodes of bleeding complications. Isolated FX deficiency may be hereditary but should--in the clinical context--also evoke the diagnosis of systemic amyloidosis. The possible bleeding tendency associated with amyloidosis is not attributable to acquired FX deficiency alone, but may also be caused by amyloid deposition in the microvasculature leading to acquired vascular hemorrhagic diathesis.