Coagulation 2 Flashcards

(57 cards)

1
Q

Platelets are produced from?

A

Cytoplasmic projections of megakaryocytes

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2
Q

Production of platelets is regulated by? What receptor does this interact with?

A

Thrombopoietin which interacts with the c-MPL receptor

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3
Q

Where is thrombopoietin produced?

A

The liver and bone marrow stromal cells

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4
Q

How long do platelets circulate for?

A

7-10 days

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5
Q

What 3 things are secreted by platelets once activated?

A
  1. Dense granules
  2. Alpha granules
  3. Acid hydrolase
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6
Q

What is the role of TXA2?

A

Prevents further activation by the agonist

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7
Q

What inherited disorders can cause platelet issues?

A

Albinism, deafness, and nephritis

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8
Q

What systemic diseases can lead to platelet issues?

A

Renal, hepatic, and myeloproliferative disease

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9
Q

What are the two types of quantitative disorders?

A

Thrombocytopenia where the count is reduced

Thrombocytosis where the count is raised

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10
Q

What 3 things can cause thrombocytopenia?

A

Decreased production, increased destruction, and splenomegaly

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11
Q

What can cause thrombocytosis?

A

Reactive to infection and autonomous

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12
Q

What is the normal range for platelet count?

A

150000-400000

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13
Q

What is pseudothrombocytopenia?

A

When there is clumping of platelets in the presence of EDTA leading to a lower count. Caused by EDTA-dependent antibodies

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14
Q

What 3 things can cause thrombocytopenia?

A
  1. Marrow replacement
  2. Marrow failure as seen in aplastic anemia where fibrosis takes over
  3. Marrow injury from radiation or drugs
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15
Q

What are the 2 types of inherited thrombocytopenias with small platelets?

A

Wiskott-Aldrich and X-linked thrombocytopneia

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16
Q

What is the main thrombocytopenia with normal sized platelets?

A

Familial platelet disorder with predisposition to AML

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17
Q

What are 2 types of thrombocytopenia with large platelets?

A

Bernard-Soulier and grey platelet syndrome

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18
Q

What is the most common thrombocytopenia due to increased destruction>

A

Immune thrombocytopenic purpura

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19
Q

What 4 drugs can cause increased platelet destruction?

A

Heparin, quinidine, vancomycin, and GPIIb antagonists

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20
Q

Post transfusion purpura occurs in those lacking what antigen?

A

HPA-1a antigen

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21
Q

Most cases of immune thrombocytopenic purpura are?

A

Acute

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22
Q

Acute ITP is usually preceded by?

A

Viral infection

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23
Q

Does chronic ITP have something preceding it?

A

No insidious onset

24
Q

In isolated thrombocytopenia platelets count will be? What other findings?

A

Less than 100,000 and they will be large.

Increased megakaryocytes in bone marrow and increased platelet associated IgG

25
Heparin caused what type of thrombocytopenia? This is most common with what type of heparin?
Immune mediated Heparin of high molecular weight
26
The reduced count results in?
Venous and arterial thrombosis, limb loss, death
27
How do you treat heparin induced thrombocyto?
Discontinue heparin and use a thrombin inhibitor like argatroban or recombinant huridin (refludan)
28
What are the 3 non-imune associated thrombocytopenias?
1. DIC 2. Hemolytic uremic syndrome 3. Thrombotic thrombocytopenic purpura
29
What causes TTP?
Reduced ADAMTS-13 metalloprotease activity
30
How does heparin cause problems?
Binds to PF4 on the platelet leading to an Ig form in against the complex
31
Hemolytic uremic syndrome occurs in?
Infants and young children
32
What does hemolytic uremic syndrome cause? What causes it?
Bloody diarrhea Infection by E. Coli O157:H7
33
How does hemolytic uremic syndrome differ from TTP?
Less pronounced neurologic symptoms and more pronounced renal symptoms. There is normal ADAMTS13
34
How is hemolytic uremic syndrome treated?
Dialysis
35
What are the two types of congenital qualitative disorders?
Disorders of membrane glycoprotein and disorders of intracellular proteins
36
How is Bernard Soulier syndrome inherited and what does it cause?
Autosomal recessive, leads to abnormal platelet adhesion
37
There is a defect in what gene in Bernard Soulier?
GP1b gene
38
How is Bernard Soulier treated?
DDAVP or PLT transfusion
39
Other than Bernard Soulier what other disorder can cause aggregation problems?
Glanzmann thrombasthenia
40
How is TTP treated?
Plasmapheresis and steroids
41
How is hemolytic uremia treated?
Dialysis
42
Describe the appearance of platelets in Bernard Soulier.
Giant platelets with a pseudonucleus
43
What are the 4 diseases of dense granule storage pool deficiency?
1. Hermansky Pudiak 2. Chediak-Higashi 3. Thrombocytopenia with absent radii 4. Wiskott-Aldrich
44
Hermansky Pudiak presents with?
Severe oculocutaneous albinism
45
Chediak Higashi presents with?
Partial albinism, large cytoplasmic granules, defective WBC function
46
Defects in thromboxane synthesis occur due to?
Defects in the AA pathway
47
What is an extrinsic acquired qualitative disorder?
Normal platelet but bad environment
48
What are the 2 causes of extrinsic qualitative
Uremia and paraproteinemia where IgG coats the platelets
49
What two things can cause intrinsic qualitative disorders?
Drugs and myeloproliferative neoplasms
50
What is the most frequent inherited bleeding disorder?
von Willebrand disease
51
How is vWF stored?
Weibel-palade bodies in endothelial cells and alpha granules of platelets
52
What are the two general functions of vWF?
Adhesion and a carrier protein for factor 8
53
What can exacerbate bleeding in those with vWF disease?
Aspirin
54
What types of vWF disease lead to severe bleeding episodes?
2 and 3
55
How much deficiency is there in vWF type 1? Leads to mild/moderate/severe disease?
Partial deficiency with normal vWF, mild to moderate disease
56
Type 1 or 3 makes up the majority?
Type 1
57
Describe vWF disease type 3.
Severe disorder, total or near deficiency of vWF, secondary deficiency of factor 8 and defect in clotting