Freda Gardner, MD, Senior Assistant Resident, The Jewish Hospital of St Louis: A 42-year-old woman was in good health until four weeks prior to her admission, when she noted that minor trauma caused large ecchymotic lesions. One week prior to admission, she experienced the sudden onset of dysarthria, weakness and paresthesias of her right arm, light-headedness, and severe bifrontal headache. This episode lasted for 30 minutes and slowly resolved. At this time the patient also noted petechiae on both lower extremities. The patient had at least three more episodes of transient dysarthria and weakness of both legs. She also complained of transient visual field defects, occasional intermittent fevers (temperatures to 38.3 °C), weakness, and fatigue. There was no history of syncope, seizures, chills, night sweats, recent travel, or exposure. She was initially hospitalized elsewhere, where the laboratory data indicated a hematocrit reading of 28% and hemoglobin level of 9 g/dL;