Thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura

Updated: 07/25/2023

© Jun Wang, MD, PhD

General features

• Thrombocytopenia resulted from small vessel thrombosis
• Need to be differentiated from hemolytic-uremic syndrome

Clinical presentations

• Pentad
• Microangiopathic hemolytic anemia
• Thrombocytopenic purpura
• Neurologic abnormalities: Alteration of mental status, seizures, hemiplegia, paresthesias, visual disturbance, and aphasia
• Fever
• Renal disease: Abnormal renal functions
• May have history of bloody diarrhea, need to differentiate from HUS

Key pathogenesis

• ADAMTS13 (Adam is 13) deficiency associated ultra-large von Willebrand factors
• Deficiency can be either congenital or due to autoantibodies
• Endotoxic (Escherichia coli O157:H7 and Shigella dysenteriae serotype I) induced endothelial cell secretion of ultra-large von Willebrand factors
• Ultra-large von Willebrand factors tends to promote platelet adhesion and aggregate, resulting in thrombosis
• Medications: Mitomycin, cyclosprorin A, cisplatin, etc
• Pregnancy, probably anti-endothelium autoantibodies

Key Laboratory findings

• Thrombocytopenia
• Hemolytic anemia
• Hemoglobinuria
• Other lab findings of hemolysis
• Fragmented red cells (Schistocytosis)
• Usually normal PT, aPTT, D-dimers (different from coagulative disorders, DIC)
• Fibrinogen may be elevated
• Low ADAMTS13 quantity/activity

Key morphological features

• Fragmented red cells (Schistocytosis)
• Megakaryocytic hyperplasia
• Hyaline thrombi in small arterioles

Differential diagnosis

Management

• Medical emergency
• Plasma exchange
• Cryopoor plasma or corticosteroid
• NO platelet transfusion

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