Case 133

1. Presented by Curtis Gravenmier, M.D., and reviewed by Ivo Francischetti, M.D., Ph.D.

An adult female presents with a lifelong history of easy bruising, heavy menses, and prolonged bleeding after tooth extraction and childbirth. She once required red cell transfusion for blood loss. Her sibling may also be affected by a bleeding disorder. An initial workup shows normal prothrombin time, activated partial thromboplastin time, thrombin time, factor activities, von Willebrand factor antigen, and ristocetin cofactor assay. A peripheral smear shows normal platelet number and morphology. Platelet aggregation results by lumi-turbidometry are provided in the attached images.

In summary, there is reduced aggregation with arachidonic acid (63%, reference range 74-99%), epinephrine (42%, reference range 78-88%), and high-dose ristocetin (47%, reference range 87-100%). Low-normal aggregation is observed with collagen (70%, reference range 70-94%). Normal aggregation is observed with ADP (81%, reference range 69-88%). However, there is severely diminished luminescence in response to collagen and thrombin. The patient was instructed to not take aspirin or other anti-inflammatory medications prior to the platelet aggregation test.


Which of the following best characterizes the bleeding disorder?