PMC5519478_01
Computed tomography of an intramuscular hemorrhage of the right quadriceps femoris muscle in a 53-year-old male patient with a spontaneous right-thigh hematoma and mild hemophilia A. An image taken at admission (A) and an image taken on day 5, which shows the worsening of the hemorrhage (B).
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An intramuscular hemorrhage of the right quadriceps femoris muscle was detected by contrast computed tomography (CT) (Fig. 1A). However, he developed severe anemia (hemoglobin: 4.9 g/dL) on day 5 after admission, and CT revealed a further intramuscular hemorrhage (Fig. 1B).
The clinical course after hospitalization of the 53-year-old male patient with a spontaneous right-thigh hematoma and mild hemophilia A. The activated partial thromboplastin time (APTT) on admission was normal. Active thigh bleeding was detected by computed tomography on day 5, and red blood cell (RBC) transfusion was required on days 5-7.
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However, because of his history, 2,000 units of recombinant FVIII (ADVATE(R)) were administered to elevate his FVIII procoagulant activity to 80% (Fig. 2).
Factor VIII/von Willebrand factor (FVIII/VWF) binding assay results in a 53-year-old male patient. A binding assay was performed in a solid-phase system using a polystyrene 96-well microtitration plate, as described previously (4). The wells were coated with monoclonal antibody to VWF. Serial dilutions of normal pooled plasma, plasma from type 2N von Willebrand disease, and the plasma from the present patient were incubated in the wells with equivalent amounts of purified FVIII. The amount of FVIII that bound to immobilized VWF was determined by measuring the FVIII coagulant activity (FVIII:C) using a chromogenic assay. The chromogenicity of FVIII:C was estimated at an optical density (OD) of 405 nm and the level of VWF binding to the coated monoclonal antibody was determined by an enzyme-linked immunosorbent assay at OD 492 nm. The FVIII:C value of the patient's plasma increased with an increase in VWF, demonstrating the normal FVIII-binding capacity of VWF.
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The FVIII/VWF binding assay showed the normal binding of FVIII to VWF (Fig. 3), ruling out a diagnosis of VWD type 2N.