Feb

4

2025

TTP – Classifications

By William Aird

Classifications

  • Thrombotic microangiopathy (TMA):
    • TTP (see below)
    • Hemolytic uremic syndrome:
      • Infection-associated HUS (IA-HUS)
      • Complement-mediated HUS (CM-HUS)
    • Other:
      • Connective tissue disease
      • Transplantation
      • Disseminated intravascular coagulation (DIC)
      • Pregnancy-associated TMAs:
        • HELLP syndrome
        • Pre-eclampsia
      • Drugs
      • Pancreatitis
      • Malignancy
      • Streptococcus pneumonia
  • MAHA:
    • In presence of platelet or fibrin clots:
      • TTP
      • HUS
      • Disseminated malignancy
      • Malignant hypertension
      • Severe preeclampsia
      • Cavernous hemangioma
      • Disseminated intravascular coagulation (DIC)
    • In absence of platelet or fibrin clots:
      • Prosthetic heart valves
      • Ventricular assisted devices
      • Extracorporeal membrane oxygenation
  • Thrombotic thrombocytopenic purpura (TTP):
    • Congenital TTP (cTTP) (Upshaw–Schulman syndrome)
    • Immune mediated TTP (iTTP) (also called autoimmune TTP or acquired TTP):
      • Primary iTTP:
        • No obvious underlying precipitating cause/disease.
        • ADAMTS-13 activity of< 10% with the presence of ADAMTS-13 autoantibodies.
      • Secondary iTTP:
        • Precipitating cause (underlying disorder or trigger) can be identified, including:
          • Connective tissue disease:
            • SLE
            • Sjogren’s syndrome
            • Rheumatoid arthritis
          • HIV infection
          • Cytomegalovirus infection
          • Pregnancy
          • Drugs:
            • Ticlodipine
            • Quinine
            • Simvastatin
            • Trimethoprim
            • Pegylated interferon
        • ADAMTS-13 activity of< 10% with the presence of ADAMTS-13 autoantibodies.