Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Haematology > Platelet abnormalities > Flashcards

Platelet abnormalities Flashcards

(49 cards)

Start Studying
1
Q

Where are platelets produced?

A

Bone marrow cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are platelets?

A

Anucleate fragments of megakaryocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the lifespan of platelets?

A

7-10 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is platelet lifespan shorter in bleeding?

A

Because they are being consumed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens to old platelets?

A

They are phagocytosed by splenic macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the normal platelet count?

A

150-400 x10^9 /L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give 3 important platelet receptors

A
  1. Thromboxane A2 (TXA2)
  2. P2Y12
  3. Glycoprotein IIb/IIIa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the thromboxane A2 (TXA2) receptor do?

A

Induces platelet aggregation and vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is P2Y12 activated by?

A

ADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the P2Y12 receptor do?

A

Amplifies activation of platelets and helps activate glycoprotein IIb/IIIa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the glycoprotein IIb/IIIa receptor do?

A

Acts as a receptor for fibrinogen and von Willebrand factor (vWF) and aids platelet adherence and aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What test would you do to investigate platelet number?

A

Full blood count

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What test would you do to investigate platelet appearance?

A

Blood film

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What test would you do to investigate platelet function?

A
  • Platelet function analyser (PFA) i.e. response ti aggregating agents e.g. ADP, collagen
  • Bleeding time (unreliable)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What test would you do to investigate platelet surface proteins?

A

Flow cytometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give 4 clinical features of platelet dysfunction

A
  1. Mucosal bleeding 2. Easy bruising
  2. Petechiae, purpura
  3. Traumatic haematomas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Give some congenital conditions which reduce platelet function

A
  1. Storage pool disorders
  2. Glanzmann’s thrombasthenia
  3. Bernard Soulier syndrome
  4. von Willebrand disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is Glanzmann’s thrombasthenia?

A

Reduction/deficiency of fibrinogen receptor glycoprotein IIb/IIIa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is Bernard Soulier syndrome?

A

Reduction/deficiency of von Willebrand receptor glycoprotein Ib

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Give 2 conditions which will cause acquired platelet fuction problems

Study These Flashcards
A
  1. Medication e.g. aspirin

2. Uraemia

21
Q

How does clopidogrel work?

Study These Flashcards
A

It impairs P2Y12 receptor on platelets

22
Q

How does tirofiban work?

Study These Flashcards
A

Interferes with glycoprotein IIb/IIIa receptor

23
Q

How does aspirin work?

Study These Flashcards
A

It is a COX-1 inhibitor which inhibits arachidonic acid synthesis

24
Q

What is thrombocytopenia?

Study These Flashcards
A

Deficiency of platelets in the blood

25
What is congenital thrombocytopenia?
Absent/reduced/malfunctioning megakaryocytes in bone marrow
26
Give some conditions which cause infiltration of the bone marrow
* Leukaemia * Metastatic malignancy (breast and prostate) * Lymphoma * Myeloma * Myelofibrosis
27
Name some conditions which can cause reduced platelet production by bone marrow
* Low B12/folate * Reduced thrombopoietin (TPO) e.g. in liver disease * Medication e.g. methotrexate and chemotherapy * Toxins e.g. alcohol * Infections e.g. viral (HIV) or TB * Aplastic anaemia (autoimmune)
28
Name a condition which can cause dysfunctional platelet production in bone marrow
Myelodysplasia
29
Name an autoimmune condition which increases platelet destruction
Immune thrombocytopenia purpura (ITP) - primary or secondary
30
Give some conditions which cause the increased consumption of platelets
* Disseminated intravascular coagulopathy (DIC) * Thrombotic thrombocytopenic purpura (TTP) * Haemolytic uraemic syndrome (HUS) * Haemolysis, elevated liver enzymes and low platelets (HELLP) – often in pregnancy * Major haemorrhage
31
What is immune thrombocytopenia?
IgG antibodies form against the platelet and megakaryocyte surface glycoproteins
32
When might primary immune thrombocytopenia occur?
Sometimes after a viral infection/immunisation
33
When might secondary immune thrombocytopenia occur?
In association with malignancies e.g. CLL or infections e.g. HIV, hepatitis C
34
How might you treat immune thrombocytopenia?
* Immunosuppression e.g. steroids, IV immunoglobulin * Treat underlying cause * Platelets if bleeding * Tranexamic acid
35
What does tranexamic acid do?
Inhibits fibrin breakdown and is good to stop mucosal bleeding but not urinary tract bleeding
36
What is disseminated intravascular coagulation (DIC)?
Small blood clots develop throughout the bloodstream, blocking small bold vessels
37
What does SIRS stand for?
Systemic inflammatory response syndrome
38
What happens in DIC?
Cytokine release in response to SIRS leads to a massive activation of the coagulation cascade
39
What is the clinical presentation of DIC?
* The patient is often acutely ill in shock * Bleeding * Bruising * Confusion * Thrombotic events
40
What might you investigate in suspected DIC?
* Look for underlying cause | * FBC, prothrombin time (PT), d-dimer
41
Name some conditions which may cause SIRS
* Sepsis * Major trauma and tissue destruction * Malignancy * Pancreatitis * Obstetric emergency
42
How might you treat DIC?
* Treat underlying cause | * Support with platelets, clotting factors, fibrinogen and blood transfusion if bleeding
43
What is thrombotic thrombocytopenic purpura?
Spontaneous platelet aggregation in the microvasculature due to reduction in the protease enzyme ADAMTS-13
44
What does the protease enzyme ADAMTS-13 do?
It is normally responsible for degradation of vWF
45
Give some causes of thrombotic thrombocytopenic purpura
* Idiopathic * Autoimmune e.g. SLE * Cancer * Pregnancy * Drug associations e.g. quinine
46
What is the clinical presentation of thrombotic thrombocytopenic purpura?
* Florid purpura * Fever * Fluctuating cerebral dysfunction * Haemolytic anaemia with red cell fragmentation, often accompanied by AKI
47
How would you diagnose thrombotic thrombocytopenic purpura?
* Coagulation screen is normal | * Lactate dehydrogenase is raised as a result of haemolysis
48
How would you treat thrombotic thrombocytopenic purpura?
* Urgent plasma exchange * Immunosuppression e.g. IV methylprednisolone * IV rituximab
49
What should you not give in thrombotic thrombocytopenic purpura and why?
Platelets because this increases thrombosis

Haematology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions