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Flashcards in Thrombocytopenia Deck (52):
1

What is thrombocytopenia?

Low platelets

2

What are the three underlying causes of thrombocytopenia?

Underproduction
Destruction
Sequestration

3

What is the normal ranges of platelets?

150-450k

4

How big are platelets relative to RBCs?

1/3 size

5

What is the cell that produces platelets?

Megakaryocytes

6

What is the chemical that determines the rate and amount of platelet production?

Thrombopoietin

7

What are the receptors on platelets that binds to vWF, and serves as an intracellular signal?

Gp IIb/IIIa

8

Stocking distribution of paresthesias with low pancytopenia =?

Pernicious anemia

9

Where are platelets sequestered, generally?

Spleen

10

What are the viral causes of thrombocytopenia? (2)

HIV
Parvo B19

11

Pts with sickle cell disease are susceptible to what viral infections?

Parvovirus B19

12

What are the two common causes of thrombocytopenia that fall under the medication/drug category?

EtOH
Chemotherapeutic agents

13

What are the three causes of marrow replacement that causes thrombocytopenia?

Granulomatous disease
Myelofibrosis
Malignancies

14

If the MCV is greater than 115, what is the disease?

megaloblastic anemia

15

What are the two platelet dysfunctions with pernicious anemia?

Diminished platelet aggregation

Decreased release of ATP, ADP

16

Elevated methylmalonic acid levels = ?

Pernicious anemia

17

What are the tests to diagnose pernicious anemia? (3)

Anti-parietal cell
Anti IF
EGD

18

What is the treatment for pernicious anemia?

SQ B12 replacement (can't give PO d/t lack of IF)

19

Why is an EGD indicated for pernicious anemia?

Gastric adenocarcinoma

20

What is pseudothrombocytopenia?

Platelet aggregation or clumping in the test tube (in vitro)

21

What is the solution to pseudothrombocytopenia?

Use a blue top tube with heparinized blood

22

thrombocytopenia with o/w normal CBC + bleeding from gums + mucocutaneous petechial rash = ?

ITP (immune thrombocytopenia purpura)

23

What is ITP?

Accelerated destruction of platelets by immune destruction

24

How do you diagnose ITP?

Diagnosis of exclusion

25

What are the results of a bone marrow biopsy with ITP?

Normal to increased number of megakaryocytes

26

The incidence of ITP increases or decreases with age

Increases

27

What are the antiplatelet abs that are involved in ITP targeted against?

IgG to GPII/IIIa receptor

28

True or false: transfusions to pts with ITP still result in destruction of platelets

True

29

What are the usual symptoms of ITP?

Purpura/petechiae
Epistaxis/bleeding gums
Menorrhagia

30

What is the first line of drug treatment for ITP? Second? Third?

IV corticosteroids

IVIG

Rituximab

31

What is the last resort for ITP treatment?

Splenectomy

32

What is antiphospholipid antibody syndrome?

Abs to GPIIa/IIIb

33

Is HUS/TTP immune mediated?

no

34

HELLP syndrome is indicated by what? (3)

Low platelet
HTN
elevated LFTs

35

HIT is caused by what?

Immune mediated destruction of platelets after exposure to heparin

36

What do abs in HIT attach to?

heparin and PF4 complex

37

What type of heparin has a lower risk of HIT?

Low molecular weight heparin

38

What happens to HIT pts when they are left untreated?

Thromboses form

39

How do you manage HIT?

Stop heparin
Change anticoag

40

True or false: you can administer heparin in pts who have had HIT before?

True, but needs to be more than 6 months

41

Jaundice everywhere but the sclera is what?

NOT hyperbilirubinemia--Hyperbetacarontenamia

42

Thrombocytopenia d/t to sequestration generally results in what PE findings?

Splenomegaly

43

What are the four causes of splenic sequestration?

1/ Hereditary spherocytosis
2. CML
3. Hairy cell leukemia
4. MALT lymphoma

44

True or false: DM is a common cause of liver cirrhosis

True

45

What are the three components of thrombocytopenia?

1. Careful H&P
2. Lab eval
3. Bone marrow biopsy

46

What are the three things to look for in a PE of thrombocytopenia?

Mucocutaneous exam
Lymphadenopathy
Splenomegaly

47

What are the two diseases that contraindicate platelet transfusion? Why?

ITP
HIT

May accelerate platelet destruction

48

For every unit of blood, how much increase in platelets should you expect?

5k

49

What are the three things that should be a part of a PE for pts with thromboytopenia?

Mucocutaneous
Lymph
Spleen

50

When is a bone marrow biopsy indicated?

2 or more cell lines affected

51

What is the more common cause of underproduction thrombocytopenia?

Drugs

52

What is the tube that should be used to r/o pseudothrombocytopenia?

Blue top