A 28 year-old man presented to the emergency department 10 days earlier with new onset shortness of breath and chest pain. Imaging revealed a segmental pulmonary embolus. He was started on lovenox, transitioned the next day to rivaroxaban and then discharged home. One week later, he developed acute onset abdominal pain. He returned to the emergency room, where a CTA revealed small left upper quadrant para-aortic retroperitoneal bleed. Rivaroxaban was He has a past history of thrombocytopenia, with platelet counts ranging between 100-150 x 109/L. He has never seen a hematologist. He has no family history of bleeding, easy bruising or coagulopathy. He is a non-smoker and drinks 1-2 beers each day. He works in computer software. He takes over-the-counter vitamin supplements, and has no known allergies to medicines.