Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Haematology > Clotting disorders > Flashcards

Clotting disorders Flashcards

1
Q

Haematology : Primary Haemostasis

A

1 . __Endothelial injury__
* Endothelin released causing vasospasm of smooth muscle

2 . Post injury - Endothelial collagen exposure

3 . Von Willibrand factor
* Released by damaged endothelial cell
* Bind to exposed endothelial collagen

4 . Adhesion
* Platelets bind to VWF on collagen via GP1B surface protein } Activates platelets

5 . Activation of platelets - causing release of;
I) VWF - attract more platelets
I) Adenosine diphosphate (ADP) and Thromboxane A2
* Act on free platelets : cause expression of GPIIB/IIA surface protein

6 . Fibrinogen - circulating blood protein
* Binds to GPIIB/IIA surface protein on platelets } ties them together

7 . Platelet plug formed
* NO + Prostaglandin release by undamaged endothelial cell - platelet inhibitor to manage size of plug

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

Haematology : Secondary Haemostasis - Extrinsic athway

A

Process of forming a fibrin mesh to reinforce the platelet plug

1. Damaged blood vessel - exposes smooth muscle
* Smooth muscle : Tissue Factor 3 on surface

2 . Factor VII (7) binds to a Factor III (3) and a calcium ion
* VIIa-TF complex on the surface of the smooth muscle cells

3 .IIa-TF complex cleaves clotting factor X
* Factor X —activated—> Factor Xa (10a)

4 . Factor Xa (10a) activates Factor V (5)
* Factor Va (5a)

5 . Factor Va (5a) binds to Ca2+ ion
* *Prothrombinase complex*

6 . Prothrombinase complex activates Factor II (2) (Prothrombin)
* Thrombin (Factor IIa (2a))

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

Haematology : Secondary Haemostasis - Post Factor 2 activation

A

__Factor II (2) activates to following clotting factors;__

1. Factor V (5) } common pathway

2. Factor VIII (8)

Fibrin mesh formation

3 . Fibrinogen (Factor 1) —> Fibrin (Factor Ia)
* Fibrin tether platelets to one another and hold the platelet plug together

4 . Factor XIII (13) —> Factor XIIIa (13a)
i) Factor XIIIa (13a) + Calcium ion
* Reinforces fibrin mesh - by forming crosslinks between Fibrin chain

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

Haematology : Instrinsic Pathway

A

1. Factor XII (12) + Phosphate ion —-activation—> Factor XIIa (12a)
* PO4- ion on surface of activated platelets/endothelial collagen from injury

2. Factor XII (12) activates Factor XI (11)
* Factor XIa (11a)

3. Factor XIa (11a) activates Factor IX (9)
* Factor IXa (9a)

5. Factor IX (9) —Factor XIa (11)——-activation —-> Factor IXa (9a)

6. Factor IXa (9) + Ca2+ion + Factor VIIIa (8a) complex } activates Factor X
* Factor Xa (10a)

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

Haematology : Common Pathway

A
  1. Factor X (10) is cleaved -> Factor Xa (10a)
  2. Factor Xa (10a) + Factor V (5) -> Factor Va (5a)
  3. Factor Xa (10a) + factor Va (5a) + calcium -> Prothrombinase complex
  • Prothrombin (FactorII) —> thrombin (factor IIa)

Thrombin activates platelets, cofactors ( V, VII, IX);

  • Cleaves fibrinogen
  • Stabilising factor -> factor XIIIa + calcium -> cross-links in mesh
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Vitamin K : Physiology

A

Fat soluble vitamin K (phylloquinone)
1. Stomach absorption : via emulsification by bile salts
2. Small intestine : integrated into chylomicrons
Transported via portal circulation
3. Liver : Vitamin K used to synthesis
* Clotting factors : II, VII, IX, X
* Anticoagulant : Protein C and Protein S -

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

Vitamin K deficiency : Causes

A

1 . Issues with fat absorption :
* Diseases of small intestine/gall bladder
* Prolonged use of abx - elimination of gut flora/diarrhoea

2 . Liver disease: unable to synthesise coagulation factor/anticoagulant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Vitamin K deficiency : Diagnosis

A

Prothrombin time + APTT + INR } Prolonged

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

Vitamin K deficiency : Management

A

1 . SC injection of Phytonadione
2 . Increase consumption of dietary vitamin K - ie. Green, leafy vegetables

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

Vitamin K : Production of clotting factors

Which clotting factors?

A

Vitamin K is important in the production of coagulation factors;
(extrinsic pathway)
__1. Factor 2 (Prothrombin)__
__2. Factor 7__
__3. Factor 9__
__4. Factor 10__

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

Warfarin MOA

A
  1. Inhibits production of Vitamin K
  2. Prevents co-factors 1972
  3. Protein C
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Partial Thromboplastin time : MOA

A
  1. Partial thromboplastin time
    * Activity of Intrinsic pathway factors
    * Factor 8, 9, 11, 12
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

INR : Definition

A
  1. Standardised version of Prothrombin time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Haemophilia A : Definition

A
  1. Most **common inherited haemophilia **
  2. X linked recessive disorder of factor IX (9)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Haemophilia A : Pathophysiology

A
  1. Deficiency in Factor 8
  2. Leads to : Impaired inactivation of intrinsic pathway —> Defect in common coagulation pathway
  3. Increased bleeding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Haemophilia A : Clinical features

A

1. Haemoarthrosis within joints
2. Spontaneous bleeding - easy bruising, haematoma

17
Q

Haemophilia A : Diagnosis

A
  1. __Partial thromboplastin time__ : ___Prolonged___ - Intrinsic pathway affected
  2. __Prothrombin time__ : ___Normal___ - Extrinsic pathway not affected
  3. Platelet count : Normal
18
Q

Haemophilia A : Management

A
  1. Desmopressin : stimulates von Willebrand factor release, promotes stabilisation of residual factor VIII release.
  2. Factor VIII infusions
19
Q

Haemophilia B - Definition

A

X linked deficiency of factor 9 affecting the clotting in the intrinsic pathway

20
Q

Haemophilia B - Pathophysiology

A

1.. Deficiency in Factor 9 protein

2.. Intrinsic pathway affected : Factor 9 combines with Factor 8 to activate factor 10

3. Impaired Haemostasis

21
Q

Haemophilia B - Diagnosis

A
  1. Partial thromboplastin time : ___Prolonged___ - Intrinsic pathway affected
  2. Prothrombin time : Normal - Extrinsic pathway intact
  3. Factor IX clotting levels : Low
22
Q

Haemophilia B - Management

A

1. Factor IX infusion
(Desmopressin is not effective - stimulates vWF which only stabilises factor VIII)

23
Q

Von Willebrand disease : Definition

A
  1. Inherited autosomal dominant mutation of allele
    * Leading to : Insufficient production of vWF factor
    * Most common inherited bleeding ddisorder
24
Q

Von Willebrand disease : Pathophysiology

A

1. Von Willebrand factor
* synthesised and stored in the endothelial (blood vessel) cells and platelets.

2. Injury to blood vessel
* releases histamine and thrombin which stimulates endothelial/platelet cells to produce vWF factor

3. WF factors works to :
* Attach to platelet receptors and binds platelets to site of injury
* Binds to Factor VIII to prevent degradation by protein C + protein S

4. Deficiency of function/amount of vWF leads to __impairs platelet aggregation__
- causes dysfunction of factor VIII.

25
Q

Von Willebrand disease : Clinical features

A

Excessive bleeding from minimal trauma ;
* Epitaxis
* Mucosal bleeding
* Menorrhagia

Typically no haemotoma/haemoarthrosis

26
Q

Von Willebrand disease : Diagnosis

A

VwF deficiency leads to low Factor 13 levels
1. APTT time : Prolonged
1. Low Factor 8 levels : higher rate of breakdown from Protein C/S

27
Q

Von Willebrand disease : Management

A

1. Tranexamic acid : mild bleeding
2 . Desmopressin :
* Raises levels of vWF
* induces release of vWF from Weibel-Palade bodies which are storage granules of vWF in endothelial cells

28
Q

Direct factor Xa inhibitors : Example

A
  1. Rivoroxaban
    * Excreted by Liver
  2. Apixaban
  3. Endoxaban
29
Q

Direct factor Xa inhibitors :Reversal

A

Andexanet alfa* except for Endoxaban

*Andexanet alfa is a recombinant form of human factor Xa protein

30
Q

Direct thrombin inhibitor : Example

A

Dabigatran

31
Q

Direct thrombin inhibitor : Reversal

A

Idarucizumab

32
Q
A

would typically feature constitutional symptoms, as well as bleeding and recurrent infections.
Neutropenia and thrombocytopenia
Acute rapid production of immature cells
Chronic - mature cells, elevated lymphocytes, CML granulocytosis

Haematology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions