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Platelet Disorders - Coggle Diagram

- - - - Defect in glycoprotein 2b3a
    - - Defect in glycoprotein 1bIX
    - - thrombocytopenia, eczema, immunodeficiency
- - - - Pathophysiology: disseminated microvascular thrombi, with consumption of platelets and clotting factors, and erythrocyte shearing injury leading to hemolysis
      - Rx: Platelet transfusion, cryoprecipitate, fresh frozen plasma
    - - TTP
        
        Pathophys: Deficiency in ADAMTS13
        
        Dx: ADAMTS13 level <10%
        
        Clinically: Fever, anemia, thrombocytopenia, renal injury, neurological changes
        
        Rx: Therapeutic plasma exchange
        
        Rx: Steroids, PLEX, rituxan
        
        Rx: Rituximab for refractory disease
      - HUS
        
        Clinically: MAHA, thrombocytopenia, AKI, diarrhea
        
        Pathophys: enterotoxin producing E. Coli O157:H7, Shiga toxin
        
        Rx: Supportive
        
        Atypical HUS
        
        Pathophys: Complement dysregulation
        
        Rx: Eculizumab with plasma exchange
        
        Rx (if severe): Plasma exchange
        
        Dx: Stool culture and PCR for shiga toxin or O157:H7 antigen testing
      - MAHA
        
        Elevated LDH
        
        Decreased haptoglobin levels
        
        Schistocytes on peripheral blood smear
        
        Negative direct antiglobulin test
  - - - Pathophys: Autoantibodies against glycoproteins on platelet surface membrane
      - Suspect if platelets <100k
      - Testing for HIV and Hep C should be performed
      - Rx: Steroids, IVIG (if severe), splenectomy, rituximab, or thrombopoietin receptor agonists (if refractory)
    - - Type I
        
        *Non-immune mediated
        
        Suspect if thrombocytopenia occurs in first few days after heparin exposure
        
        typically does not require tx
      - Type II
        
        Pathophys: Antibodies against platelet factor 4
        
        Clinically: Thrombosis, PE, acute arterial occlusions
        
        Suspect if platelet count <150k and if plts decrease by > 50% after receiving heparin products
        
        Dx: 4T scoring system, serotonin release assay, heparin-induced platelet aggregation assay
        
        Dx: Test for platelet factor 4 antibodies with confirmation with serotonin release assay
        
        Rx: Use argatroban, fondaparinux, or a NOAC for anticoagulation