PLT Destruction

Audio Overview

Definition: A group of disorders characterized by a decreased platelet count (<150 x 10^9/L) resulting from the accelerated destruction or consumption of platelets
Key Distinctions
- Differentiating between increased destruction and decreased production is key. The bone marrow response (megakaryocyte number and activity) is essential for this distinction
- A normal, or even increased, megakaryocyte number in the bone marrow suggests that the problem lies in the destruction of platelets
General Mechanisms
- Immune-Mediated Destruction: Antibodies or complement proteins bind to platelets, leading to their destruction by the mononuclear phagocyte system (MPS) or through complement-mediated lysis
- Non-Immune-Mediated Destruction: Platelets are mechanically damaged or consumed in thrombotic microangiopathies (TMAs)
- Sequestration: Platelets are trapped in the spleen due to splenomegaly

Complete Blood Count (CBC)
- To evaluate platelet count and other blood cell parameters
Peripheral Blood Smear Examination
- To assess platelet morphology and rule out other causes of thrombocytopenia
Direct Antiglobulin Test (DAT)
- To rule out immune hemolysis
Coagulation Studies (PT, aPTT, Fibrinogen, D-dimer)
- To rule out DIC
ADAMTS13 Activity Level
- To diagnose TTP
Stool Shiga Toxin Assay
- To diagnose typical HUS
HIT Antibody Testing
- To diagnose heparin-induced thrombocytopenia
Bone Marrow Aspiration and Biopsy
- To evaluate megakaryocytes and rule out other bone marrow disorders