A 67-years old woman developed sudden headache and transient vertigo. One week later, left arm paresis appeared and the patient became comatose. Investigations showed thrombocytopenia with hemolytic anemia and the presence of numerous irregularly contracted red cells (schizocytes). This was consistent with the diagnosis of thrombotic thrombocytopenic purpura. As focal neurological manifestations and widespread mental changes were still present when she emerged from coma, magnetic resonance imaging was performed showing numerous small infarcts in the white and grey matters.