Platelet Disorders

Front 1

What is it called when there are too FEW platelets? Cuses?

Back 1

Thrombocytopenia

Decreased production
Increased degradation

Front 2

What is it called when there are too many platelets?

Back 2

Thrombocytosis

Front 3

How are platelets produced from megakaryocytes?

Back 3

Budding

Front 4

What's the lifespan of a platelet?

Back 4

5-9 days

Front 5

What is the normal platelet count?

Back 5

150-400E9/L

Front 6

What protein regulates platelet production?

Back 6

Thrombopoietin

Front 7

What organs recycle platelets?

Back 7

Spleen
Liver

Front 8

What cells in the liver destroy platelets?

Back 8

Kupffer cells

Front 9

What is a storage site for platelets?

Back 9

Spleen

Front 10

What causes platelets to be released by the spleen?

Back 10

Sympathetic activation

Front 11

What levels of platelets are associated with increased risk of spontaneous hemorrhage? Spontaneous intracranial hemorrhage?

Back 11

Spontaneous: <20,000

Intracranial: <10,000

Front 12

What is the platelet cutoff for general surgery?

Back 12

60,000/uL

Front 13

What are some causes of prolonged bleeding in the context of a normal platelet count?

Back 13

Asprin (think decreased thromboxane-->decreased activation )
Uremia (altered prostaglandins/thromboxane-->decreased activation)
von Willebrand

Front 14

What are some causes of decreased production of platelets?

Back 14

Bone marrow problems!
-Primary failure
-Invasion of the marrow
-Injury to bone marrow
-Nutritional problems
-Megaloblastic anemia
-Hereditary platelet disorders

Front 15

What is the effect of alcohol on bone marrow?

Back 15

Inhibition

Front 16

What are the causes of increased platelet destruction?

Back 16

Immune mediated
Non-immune mediated

Front 17

What are some of the non immune-mediated causes of platelet destruction?

Back 17

DIC
TTP
Hypersplenism

Front 18

What is the effect of having a large spleen on blood platelet levels?

Back 18

Sucks up the platelets from the circulation

Can get levels as low as 40,000-60,000

Front 19

What are some of the immune mediated causes of increased platelet destruction?

Back 19

Immune thrombocytopenia
Neonatal autoimmune thrombocytopenia
Drug induced
Heparin induced

Front 20

What are the different types of autoimmune thrombocytopenia?

Back 20

Acute
Chronic
Secondary

Front 21

Who gets acute autoimmune thrombocytopenia?

Back 21

Children

Front 22

What are the symptoms of acute autoimmmune thrombocytopenia?

Back 22

Viral illness 3 weeks ago
Severe bleeding symptoms; self limited

Front 23

Who gets chronic autoimmmune thrombocytopenia?

Back 23

Women

20-40

Front 24

What does the bone marrow look like in chronic autoimmmune thrombocytopenia?

Back 24

Normal

Front 25

What diseases is secondary autoimmmune thrombocytopenia associated with?

Back 25

Disordered lymphoid function:
SLE
Lymphoma
CLL

Front 26

What is a good therapy for ITP?

Back 26

Splenectomy!

Front 27

What are some concerns for splenecomy in people with ITP?

Back 27

Are the antibodies produced in the marrow?
It could be the case that the platelets are destroyed somewhere else

Front 28

Other than splenectomy, what are some of the other therapies for ITP?

Back 28

IVIg
Anti CD 20 immunotherapy
Immune modulators
Platelet growth factors

Front 29

What is the cause of neonatal allo immune thrombocytopenia?

Back 29

Antibodies from mom are put into the circulation of the baby

It can be when there's a mismatch in an antigen status: mom is Pla1- and the fetus is Pla1+

Front 30

What's the timeline for platelet levels to recover after a drug-induced thrombocytopenia?

Back 30

7 days - 3 weeks

YOu need to wait until all of the drug is out of the body

Front 31

What are the two forms of heparin induced thrombocytopenia?

Back 31

Mild
Severe:
-Platelet count decreases more than 30% form baseline

Front 32

What's the treatment for heparin induced thrombocytopenia?

Back 32

Treat the thrombosis!

Front 33

What's the mechanism of heparin induced thrombocytopenia?

Back 33

1. Heparin comes into body
2. Heparin PF4 complexes form
3. Antibodies that bind to the platelets also bind to the heparin-PF4 complexes cause more activation of platelets
4. More release of PF4 (it becomes a cycle, here)

5. Endothelial cell injruy

Front 34

How long do antibodies in heparin induced thrombocytopenia stick around?

Back 34

3 months!

Beware!

Front 35

What are the causes of primary thrombocytosis?

Back 35

Clonal myeloproliferative disorders
-Chronic myelogenous leukemia
-Essential thrombocytosis
-Polycythemia vera

Front 36

Why is there often bleeding in the setting of primary thrombocytosis?

Back 36

It's often the case that despite their large numbers, the platelets are still dysfunctional

Front 37

What levels is defined as secondary thrombocytosis?

Back 37

>700,000/uL

Front 38

What are causes of secondary thrombocytosis?

Back 38

Inflammation
Hemorrhage
Post splenectomy
Iron deficiency

Front 39

What are some ways that you can assess platelet function?

Back 39

Peripheral smears
Counts: NL = 150k - 450k
Bleeding time: NL < 9 minutes
Platelet aggregation: main tool

Front 40

What are some different substances you can use to assess platelet aggregation?

Back 40

Thrombin
ADP
Epinephrine
Collagen

Front 41

What are the properties of the qualitative platelet disorders?

Back 41

Platelet function abnormalities
Normal count
Bleeding symptoms

Front 42

What are the receptors that cause interplatelet links?

Back 42

GPIIb

Front 43

What molecules cause the release reaction in platelets?

Back 43

Thromboxane

This is blocked with asprin!

Front 44

What are the different kinds of inherited disorders of platelet function?

Back 44

Platelet-vessel
Platelet-platelet
Granules, secretion, signal transduction

Front 45

What are the congenital disorders of adhesion?

Back 45

Von Willebrand's disease
Bernard soulier syndrome

Front 46

What defect is present in vWD?

Back 46

Missing a linker molecule between the platelet and the vascular endothelium

Front 47

What defect is present in Bernard Soulier?

Back 47

GpIb defect

Front 48

What are the findings in Bernard Soulier Syndrome?

Back 48

Thrombocytopenia

Giant platelets found on the smear

Front 49

What platelet aggravating factor won't vWD or Bernard Soulier patients respond to?

Back 49

Ristocetin

Front 50

What is afibrinogemia?

Back 50

Platelet and coagulation factor defect type bleeding

Fibrin just isn't there

Front 51

What protein is mutated in Glanzmann's thrombocytopenia?

Back 51

Autosomal disorder

Absent/defective GpIIbIIIa

Front 52

If you have thrombasthenia/afibrinogenemia, what platelet aggravants aren't effective?

Back 52

ADP
Epinephrine

Front 53

What are the different kinds of disorders of activation and secretion of platelets?

Back 53

Storage pool deficiency
Defectsin platelet stimulus response coupling pathways
Primary secretion defects

Front 54

What is the difference between the aggravation patterns between Glanzmann's and Bernard-Soulier?

Back 54

They're the opposite!

Front 55

What are the different kinds of acquired platelet function defects?

Back 55

Urmia
Myeloproliferative disorders
Myeodysplastic disorders, leukemia
Dysproteinemias
Cardiopulmonary bypass
Antibodies
Lung disease
Drugs

Front 56

How does uremia cause an acquired platelet function defect?

Back 56

Toxins in the wall cause abnormalities in the wall, abnoramlities in the platelet prostaglandin pathways