Oral Med

Bleeding patterns can sometimes help determine?

Cause of bleeding

Defects in primary hemostasis (4)

• Mucocutaneous bleeding

  • skin and oral cav

  • petechiae

  • heavy menstrual

  • post op bleeding

Defects in Secondary Hemostasis

• bleeding and then rebleeding pattern

  • Soft tissue bleeding

    • Muscle hematomas

    • hemathrosis

    • CNS bleeding

    • Post op bleeding

Inital Steps: vascucular injury

• arterioral vasoconstriction (ADP_

  • reduces blood flow

  • mediated by endothelin

• Exposure of subendothelial von willebrand factor (vWF) and collagen → this stimulates primary hemostasis

  • Platelet adhesion

  • platelet activation

    • shape change

    • granule release

  • Recuritment

  • Aggregation

platelet adhesion: Von willebrand factor (link protein) binds ____ and __ on platelets

collagen and glycoprotein GP-1b

Shape change in primary hemostasis

• increases SA

• more neg charged phosphilips to surface (for binding Ca)

• Conformation change in platelet glycoprotein iib/iia

Platelet aggregation

• gp iib binds fibrorinogen, forming bridges between platelets

• initial wave reversible

• Thrombin stims

  • irreversible platlet constraction

  • conversion of fibrionegen to fibrin

Primary Hemostasis requires

1. Collagen

2. vWF

3. Platelet adhesion (GP -1B)

4. Platelet aggregation (ADP, serotonin,, GPIIB)

Primary Hemostasis abnormalities

• decreased von willebrand’’s function (activity or amount (antigen)

• Decreases platelet count (CBC)

• decreased platelet Function (platelet function assay, platelet aggregation studies)

• whole blood assays: bleeding tines, thrombroelastography