🩸 Section 524.1 · Clinical and Laboratory Evaluation of Hemostasis

Nelson Textbook of Pediatrics 22nd Edition | Systematic evaluation of bleeding disorders: detailed bleeding history (site, severity, timing, family history), physical exam (petechiae, ecchymoses, hemarthrosis), screening tests (platelet count, PT, PTT, TT, fibrinogen), mixing studies, factor assays, von Willebrand panel, platelet aggregation. Developmental hemostasis: neonates have prolonged PT/PTT (physiologic) due to low vitamin K-dependent factors, protein C/S, antithrombin.

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πŸ“‹ 30 Clinical Scenarios β€” Evaluation of Hemostasis

πŸ“‡ High‑Yield Review Cards (Hemostasis Evaluation)

🩺 Bleeding History β€” Localizing the Defect

Select a presentation to identify primary vs secondary hemostatic defect.

πŸ“‹ Stepwise Diagnostic Algorithm for Bleeding Disorders

πŸ”‘ Key Principles β€” Nelson Section 524.1
β€’ Primary hemostasis defects (platelet/vWF): Mucocutaneous bleeding (epistaxis, menorrhagia, bruising), petechiae. Tests: platelet count, PFA-100, platelet aggregation, vWF panel.
β€’ Secondary hemostasis defects (coagulation factors): Deep bleeding (hemarthrosis, muscle hematomas), delayed rebleeding. Tests: PT, PTT, mixing study, factor assays.
β€’ Mixing study: Correction with normal plasma β†’ factor deficiency. No correction β†’ inhibitor (lupus anticoagulant, factor inhibitor).
β€’ Developmental hemostasis: Neonates have prolonged PT/PTT (physiologic). Use age-appropriate reference ranges.

    ⚑ Reflex Prompts β€” Clinical Decisions in Hemostasis Evaluation

    πŸ“– Summary: Clinical & Laboratory Evaluation of Hemostasis β€” Nelson 524.1