A 27-year-old woman presents with nose bleeds, rash on her feet, and fevers. She looks unwell, pale, jaundiced, and there are multiple petechiae on her feet. The lungs are clear, heart sounds normal, and abdomen is soft with no palpable spleen or liver. Her bilirubin is 2 mg/dL (mostly indirect), aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP) are normal. The hemoglobin is 8.7 g/dL, platelets 24,000/mL, PT/PTT normal, and bleeding time is elevated. The blood film reveals anemia, thrombocytopenia, and red cell fragments.For the above patient with a bleeding disorder, select the most likely diagnosis.