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Heme / Onc > SM_254b: Thrombocytopenias > Flashcards

SM_254b: Thrombocytopenias Flashcards

1
Q

Primary hemostasis is ____ and ____

A

Primary hemostasis is binding to vWF and collagen and platelet plug formation

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2
Q

Secondary hemostasis provides the co-factors ____ and ____ to the coagulation cascade factors

A

Secondary hemostasis provides the co-factors phospholipid and calcium to the coagulation cascade factors

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3
Q

Platelets are produced in the ____ from ____

A

Platelets are produced in the bone marrow from megakaryocytes

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4
Q

Platelet production is mediated by ___

A

Platelet production is mediated by thrombopoietin

  • Constitutively produced by liver
  • Removed from circulation by binding to platelets
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5
Q

Thrombocytopenia can result from ___, ___, ___, or ___

A

Thrombocytopenia can result from lack of production, destruction, redistribution, or congenital disorder

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6
Q

Describe an algorithm for thrombocytopenia evaluation

A

Algorithm for thrombocytopenia evaluation

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7
Q

Isolated thrombocytopenia, normal blood smear, and increased megakaryocytes on bone marrow biopsy should make you think of ____

A

Isolated thrombocytopenia, normal blood smear, and increased megakaryocytes on bone marrow biopsy should make you think of immune thrombocytopenia purpura

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8
Q

Describe types of thrombocytopenia

A

Thrombocytopenia

  • Mild (100,000-149,000/uL): minimal bleeding risk
  • Moderate (50,000-99,000/uL): minimal risk of spontaneous bleeding, may have bleeding with trauma and invasive procedures
  • Severe (< 50,000/uL): may have spontaneous bleeding especially <20,000/uL, bruising or petechiae are likely and common
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9
Q

Immune thrombocytopenia purpura involves ___

A

Immune thrombocytopenia purpura involves auto-antibody mediated platelet destruction (usually against GP IIb/IIIa)

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10
Q

___, ___, ___, and ___ cause secondary immune thrombocytopenia purpura

A

Lupus, malignancy, HIV, and hepatitis C cause secondary immune thrombocytopenia purpura

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11
Q

Describe the time course of immune thrombocytopenia purpura

A

Time course of immune thrombocytopenia purpura: duration of platelet count < 100,000 uL

  • Acute / newly diagnosed: < 3 months from diagnosis
  • Persistent: 3-12 months from diagnosis
  • Chronic: > 12 months from diagnosis
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12
Q

Immune thrombocytopenia purpura is treated with ____, ____, ____, ____, and ____

A

Immune thrombocytopenia purpura is treated with

  • Steroids
  • IV Ig
  • Rituximab
  • Tpo receptor agonists
  • Splenectomy
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13
Q

Describe immune thrombocytopenia in kids

A

Immune thrombocytopenia in kids

  • Usually preceded by viral illness: 3-30 days prior
  • Self-limited disease
  • Bleeding is rare even if platelet count < 20,000/uL
  • Treatment can improve platelet count in 1-4 days
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14
Q

Describe immune thrombocytopenia in adults

A

Immune thrombocytopenia in adults

  • Usually occurs absent preceding infection
  • Treatment generally recommended if platelet count < 30,000/uL, considerations for bleeding symptoms and comorbid conditions
  • High relapse rates
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15
Q

Immune thrombocytopenia purpura involves ____

A

Immune thrombocytopenia purpura involves antibody-mediated destruction within the reticuloendothelial system

  • Physiologic consumption: localized or generalized infections or bleeding
  • Occurs because platelet activation is the first step of platelet death
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16
Q

Describe mechanisms of platelet destruction

A

Mechanisms of platelet destruction

  • Other antibody-mediated destruction: heparin-induced thrombocytopenia, drug-induced thrombocytopenia, and infection-related thrombocytopenia
  • Thrombotic microangiopathies: disseminated intravascular coagulation, thrombotic thrombocytopenia purpura, hemolytic uremic syndrome, HELLP
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17
Q

Heparin-induced thrombocytopenia occurs when ____

A

Heparin-induced thrombocytopenia occurs when heparin and platelet factor 4 form a neoepitope against which IgG antibodies are made

18
Q

Patient on heparin, with new or worse thrombosis since onset of thrombocytopenia, and isolated thrombocytopenia with normal coags has ____

A

Patient on heparin, with new or worse thrombosis since onset of thrombocytopenia, and isolated thrombocytopenia with normal coags has heparin-induced thrombocytopenia

19
Q

Recent heparin use can ___, indicative of heparin-induced thrombocytopenis

A

Recent heparin use can shorten time between heparin initiation and onset of thrombocytopenia, indicative of heparin-induced thrombocytopenia

  • 5-14 days
20
Q

Patient taking heparin with reduction of platelet count by 50% from pre-heparin count has ___

A

Patient taking heparin with reduction of platelet count by 50% from pre-heparin count has heparin-induced thrombocytopenia

  • Does not technically need to be thrombocytopenic
21
Q

Heparin-induced thrombocytopenia is treated by ____

A

Heparin-induced thrombocytopenia is treated by discontinuing heparin

  • Treat with alternative anticoagulation
22
Q

Describe thrombotic microangiopathies

A

Thrombotic microangiopathies

  • Thrombosis in microvessels: usually capillaries and arterioles
  • Caused by endothelial activation or damage
  • General term encompassing multiple diseases
23
Q

Thrombotic thrombocytopenia purpura involves ____, ____, ____, ____, and ____

A

Thrombotic thrombocytopenia purpura involves thrombocytopenia, fever, altered mental status, hemolytic anemia, and renal failure

24
Q

Thrombocytopenia, intravascular hemolysis, renal failure, fever, and neurologic symptoms is ____

A

Thrombocytopenia, intravascular hemolysis, renal failure, fever, and neurologic symptoms is thrombotic thrombocytopenia purpura

25
Q

Melanin can mask ____ and ____

A

Melanin can mask petechiae and purpura

26
Q

Describe pancytopenia physical exam findings

A

Pancytopenia

  • Pallor on conjunctiva, palms, soles, nailbeds, gingiva, and tongue
  • Some with anemia can appear to have jaundice
27
Q

Low platelets, WBC, RBC, and mean cell volume is ___

A

Low platelets, WBC, RBC, and mean cell volume is pancytopenia

28
Q

Hypocellular bone marrow biopsy indicates ___

A

Hypocellular bone marrow biopsy indicates decreased platelet production

29
Q

Lack of production of platelets in bone marrow can result from ___ or ___

A

Lack of production of platelets in bone marrow can result from aplasia or myelophthisis

30
Q

Describe aplasia

A

Aplasia (lack of production)

  • Primary bone marrow failure: aplastic anemia, myelodysplasia
  • Secondary bone marrow suppression: cytotoxic medications (chemo) or radiation, viral infection

Drugs and infections can cause immune-mediated and hypoproliferative thrombocytopenia

31
Q

Describe myelophthisis

A

Myelophthisis (lack of production)

  • Cancer: leukemia, metastatic
  • Myelofibrosis
  • Osteopetrosis
32
Q

Liver failure can cause ____

A

Liver failure can cause lack of platelet production

33
Q

Insufficient nutrients such as ____, ____, and ____ may cause lack of platelet production

A

Insufficient nutrients such as Vitamin B12, folate, and copper may cause lack of platelet production

34
Q

Platelet redistribution involves ____ and ____

A

Platelet redistribution involves sequestration and dilution

  • Sequestration: platelets are in the body but not circulating in the bloodstream
  • Dilution: platelet count is measured in platelets/uL so increased volume will lead to decreased platelets/uL
35
Q

Describe platelet sequestration

A

Platelet sequestration

  • In spleen
  • Splenomegaly: porrtal hypertension, infiltrative processes (lymphoma), infection (mono), splenic sequestration crisis in patients with HbSS or HbSC
  • Mild to moderate thrombocytopenia
  • If platelet count is < 75,000/uL look for another etiology
36
Q

Describe platelet dilution

A

Platelet dilution

  • Pregnancy: increased blood volume, same rate of platelet production
  • Massive fluid resuscitation: massive transfusion that does not include platelets, large amounts of crystalloid fluids
37
Q

Describe causes of thrombocytopenia in neonates

A

Thrombocytopenia in neonates

  • Antibody-mediated: alloantibody immune thrombocytopenia, passive anti-platelet antibodies
  • Congenital platelet disorder: Bernard Soulier, Wiscott Aldrich syndrome
38
Q

Describe Glanzmann thrombasthenia

A

Glanzmann thrombasthenia

  • Not thrombocytopenia but is congenital
  • Platelet count and morphology are normal
  • Platelets are dysfunctional due to lack of GP IIb/IIIa (binds fibrinogen)
  • Bleeding symptoms are moderate to severe
39
Q

Describe Bernard Soulier syndrome

A

Bernard Soulier syndrome

  • Large platelets (macrothrombocytopenia)
  • Defect in GP Ib-V-IX (vWF receptor and part of platelet cytoskeleton)
  • Autosomal recessive
  • Moderate to severe bleeding
40
Q

Describe Wiscott Aldrich syndrome

A

Wiscott Aldrich syndrome

  • Small platelets (microthrombocytopenia)
  • Defect in WAS gene (WASp protein)
  • X-linked recessive
  • Immune deficiency, eczema, microthrombocytopenia

Heme / Onc (41 decks)

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