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Thrombocytopenia: A Brief Overview

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Platelets are produced in bone marrow from Megakaryocytes ... Bone Marrow aspiration and biopsy indicated if no other etiology obvious unless ... – PowerPoint PPT presentation

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Title: Thrombocytopenia: A Brief Overview


1
Thrombocytopenia A Brief Overview
  • Corey Cudzilo, M-3
  • 7/18/05

2
Platelets In General
  • nL platelet count in adults ranges from
    150,000-450,000/microL
  • Surgical bleeding usually does not occur until
    the platelet count is less than 50,000, and
    spontaneous bleeding does not occur until the
    platelet count is less than 10,000-20,000

3
Platelets In General
  • Platelets are produced in bone marrow from
    Megakaryocytes
  • An estimated 1000-5000 platelets are produced
    from each Megakaryocyte
  • In normal adults platelet production is
    35,000-50,000/microL of whole blood per day.
    This value can be increased 8-fold during times
    of increased demand

www.UpToDate.com 2005
4
Mechanisms of Thrombocytopenia
  • Decreased platelet production
  • Increased platelet destruction
  • Dilutional Thrombocytopenia
  • Splenomegaly or splenic sequestration
  • Pseudothrombocytopenia

5
Decreased Platelet Production
  • Usually some offense that causes bone marrow
    suppression or damage
  • Viral illness
  • HIV (direct damage to Megakaryocytes)
  • Chemo- or radiation therapy
  • Congenital or acquired bone marrow aplasia or
    hypoplasia
  • Direct EtOH toxicity
  • Vit. B12 or Folate deficiency

6
Increased Platelet Destruction
  • Idiopathic (Immune) Thrombocytopenic Purpura
  • Alloimmune destructionPosttransfusion,
    Post-transplantation
  • Disseminated Intravascular Coagulation
  • Thrombotic Thrombocytopenic Purpura
  • Antiphospholipid Antibody Syndrome
  • Certain drugsHeparin, quinidine, valproate

7
Splenic Sequestration
  • Normally, 1/3 of platelets are sequestered in
    the spleen in any given time
  • In extreme splenomegaly, up to 90 of platelets
    can be trapped in the spleen
  • Platelet size and life span is usually not
    affected
  • Cirrhosis, Portal HTN, splenomegaly can all
    present with apparent thrombocytopenia, although
    these pts are not usually at risk for clinical
    bleeding

8
Clinical Presentation
  • Asymptomatic
  • Mucosal or cutaneous bleeding
  • Petechiae
  • Purpura
  • Ecchymoses

www.UpToDate.com 2005
9
Common Presentations
10
Initial Approach
  • HP
  • Bleeding Hx
  • Drug Ingestion
  • CBC and peripheral smeargold standard
  • Bone Marrow aspiration and biopsyindicated if no
    other etiology obvious unless pt is lt60yrs old.
    The presumptive Dx in that case is usually ITP.
  • Idiopathic Thrombocytopenic Purpura (ITP) is a Dx
    of exclusion when HP,Drug ingestion,CBC, and
    peripheral smear do not suggest other etiologies

11
DDx of ITP
12
Treatments
  • ObservationUsually appropriate if platelets are
    above 20,000/microL
  • Glucocorticoids
  • Platelet Transfusion
  • In pts unresponsive to GCs, IV Ig will usually
    increase the platelet count to a safe level in
    1-3 days.

13
Sources
  • Approach to the adult patient with
    thrombocytopenia. Steven A. Landlaw, MD/PhD.
    2005. UpToDate online.
  • Evaluation and management of thrombocytopenia by
    primary care physicians. James George, MD. 2005.
    UpToDate online.
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