Thrombotic thrombocytopenia purpura

Background

• One of the thrombotic microangiopathies

Pathophysiology

• Caused by acquired or inherited deficiency of the ADAMTS13 metalloprotease
  • Acquired is via autoantibody
• ADAMTS13 normally breaks larger von Willebrand factor multimers into smaller particles
• This deficiency results in increased high-molecular-weight vWF, which aggregates and activates platelets

Clinical Manifestations

• Presents as a triad of fever, thrombocytopenia, microangiopathic hemolytic anemia, neurologic deficits, and acute renal failure
• AKI is typically less severe than HUS
• Coagulation parameters are typically less abnormal than in DIC
• In inherited ADAMTS13 deficiency, symptoms tend to start during adolescence and present in episodes