Platelets

Question 0

Function of platelets

Answer 0

They form the primary haemostatic plug
They provide a phospholipid surface on which clotting factors an work
They cross link the fibrin clot to make it stable

Question 1

Where are platelets derived from?

Answer 1

HSCs

Question 2

What I the sunendithelial matrix made of ?

Answer 2

Collegen
VWF
Tissue factors

Question 3

What activates coagulation

Answer 3

A breach in the endothelium - expose subendithelial matrix. VWF unfolds.

Always little bit happening- more in trauma

Question 4

What does VWF do?

Answer 4

Grab platelets

VWF has receptors for platelets & vice versa

Question 5

What happens when platelets bind VWF?

Answer 5

Ps become activated
Change shape
Bind to more things
Release contents (granules)
G= dense bodies & a granules

Question 6

What do granules do?

Answer 6

Attract platelets
Attract more platelets
Attract VWF

Question 7

What dos fibrin do?

Answer 7

It’s a glue!

Glues the platelet plug following activation if coagulation cascade

Question 8

What activates platelets?

Answer 8

Thrombin from CC
ADP released from dense bodies
Collagen in vessel wall
Platelets

Question 9

Platelet activation causes:

Answer 9

A shape change
Formation of pseudopodia
Granule release
Platelet attraction & aggregation 
Provide phospholipid be on which CC can work

Question 10

What do platelets bind to to form a table thrombus?

Answer 10

VWF
Collagen
Fibrin

Question 11

How can platelets go wrong?

Answer 11

To many/few

Poor quality = abnormal function

Question 12

Name an squired cause of a qualitative disorders of platelet function

Answer 12

Myelodysplasia

Bone marrow failing- cells produced are poor quality & low in number

Question 13

What drugs can interfere with platelets

Answer 13

Aspirin
NSAIDs
Clopidogrel

Question 14

What type of antagonist is clopidogrel?

Answer 14

P2Y12

Question 15

What enzyme does aspirin inhibit?

Answer 15

COX 1

Stops formation of thromboxin A2

Question 16

Name a congenial platelet disorder where they cannot bind to VWF

Answer 16

Bernard Soulier

Autosomal recessive

Rare

Question 17

What congenital condition causes lack of platelet aggregation this no platelet plug?

Answer 17

Glanzmann’s thrombasthenia

Question 18

What disease causes abnormal release of granules?

Answer 18

Pool disorders

Question 19

What is mucocutaneous bleeding?

Answer 19

Bleeding from mucous membranes

Question 20

What’s the normal platelet count?

Answer 20

150-450 ✖️ 10 power 9/ L

Question 21

What is thrombocytopenia?

Answer 21

Not enough platelets!! ❤️⬇️

< 150

Question 22

What is thrombocytosis?

Answer 22

Too many platelets! ❤️❤️❤️⬆️

> 500

Question 23

Causes of ⬆️ platelets (thrombocytosis)

Answer 23

Smoking
Splenectomy
Cancer
Iron deficiency

Question 24

What is the physiological cause of thrombocytosis?

Answer 24

Cytokine storm..... | Increase megakaryocytes

Question 25

What gene is mutated in Wiskott-Aldrich syndrome?

Answer 25

WAS gene Causes defective actin polymerisation X-linked recessive

Question 26

Symptoms of W-A syndrome?

Answer 26

Thrombocytopenia | Eczema

Question 27

What cells are found in bone marrow?

Answer 27

Lots of fat cells Megakaryocytes Myeloid precursor cells

Question 28

What condition causes bone marrow to become packed with plasma cells?

Answer 28

Myeloma Can't produce RBCs/WBCs/platelets

Question 29

What suppresses bone marrow?

Answer 29

Chemotherapy

Question 30

Leukopenia

Answer 30

⬇️ WBCs

Question 31

What conditions cause ⬇️ platelets?

Answer 31

``` Glandular fever Hypersplenism Liver cirrhosis Massive Haemorrhage Sepsis Immune ```

Question 32

What is the blood picture with increased consumption?

Answer 32

Low platelets Normal or high WBCs Low or normal RBCs

Question 33

Name some secondary causes of autoimmune thrombocytopenia

Answer 33

``` Autoimmune conditions (SLE, RA) Drugs (penicillin, quinine, abciximab, heparin) Viral infections (HIV, hep C & B) ```

Question 34

Name the primary cause of autoimmune thrombocytopenia

Answer 34

I idiopathic immune thrombocytopenia

Question 35

What is the only thing in the blood picture that is affected in ITP?

Answer 35

Platelets (reduced)

Question 36

What is ITP

Answer 36

Primary autoimmune thrombocytopenia

Question 37

What is the peak age incidence for acute & chronic ITP?

Answer 37

A = 2-8 C = older

Question 38

What causes purpuric rash?

Answer 38

Leaky endothelia

Question 39

Treatment for ITP

Answer 39

1) Corticosteroids, Ig, platelets 2) splenectomy, immunosuppression, anti-CD20 antibody 3) thrombopoietin agonist/ mimetics

Question 40

What produces thrombopoietin?

Answer 40

The liver

Question 41

Why does TPO bind to?

Answer 41

Megakaryocytes & platelets

Question 42

Normal Hb for women

Answer 42

11.5-15.5

Question 43

If platelet count goes below 10 what is probable cause?

Answer 43

Immune mediated