Bleeding Disorders Flashcards

1
Q

What are the 3 common things that can be affected that cause abnormal bleeding?

A

1 - blood vessel disorders

2 - platelet disorders

3 - coagulation disorders (clotting factors)

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2
Q

Although uncommon, what is Hereditary Haemorrhagic Telangiectasia as a form of blood vessel disorder?

A
  • Haemorrhagic = violent bleeding
  • Telangiectasia = end of blood vessels dilate
  • blood vessel dilated and swell casuing bleeding
  • common in skin and mucous membranes
  • present with nose or GI tract bleeds
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3
Q

Inherited collagen abnormalities can cause dysfuctional blood vessels. What happens in this instance?

A
  • Ehlers Danlos Syndrome is one of most common
  • small blood vessels are weak and can rupture
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4
Q

Scurvy is an acquired disorder that can affect blood vessels. How can scurvy cause this?

A
  • hypertophy of fragile blood vessels
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5
Q

What is the most commonly acquired cause of dysfuctional blood vessels?

A
  • ageing
  • collagen loses it properties and blood vessles become damaged
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6
Q

What is the normal range for platelets?

A
  • 150-400 x109/L
  • collagen is exposed to blood and activates platelets
  • this triggers coagulation cascade
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7
Q

What is thrombocytopenia?

A
  • low platelet count <150
  • BUT symptoms wont present until <10
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8
Q

In relation to bleeding, what do patients with platelet disorders generally present with?

A
  • superficial
  • epitaxis (nose bleeds), GI tract bleeds, bruising
  • petechial rash (red dots on skin)
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9
Q

What are the 4 most common causes of acquired platelet dysfunction?

A
  • bone marrow disorders (dysfunctional platelets)
  • immune thrombocytopenia (low platelets)
  • drug related (damaged platelets)
  • disseminated intravascular coagulation (DIC)
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10
Q

What is immune thrombocytopenic purpura?

A
  • immune cells attack platelets, reducing their numbers
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11
Q

Does immune thrombocytopenic purpura affect young or older people more?

A
  • more common in children who have good outcomes
  • adults less affected but need more support to recover
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12
Q

What are the treatment options for patients with chronic immune thrombocytopenic purpura?

A
  • steroids
  • immunoglobulins
  • occasionally splenectomy
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13
Q

Drugs are the most common causes of acquired platelet dysfunction. What drugs have been linked with this?

A
  • drugs (asprin, clopidogral, NSAIDs)
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14
Q

Glanzmann’s thrombocytopenia is an inherited cause of platelet disorders. How does this affect platelet function?

A
  • leads to Gp 2b/3a deficiency
  • Gp 2b/3a binds fibrinogen
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15
Q

Bernard-Soulier syndrome is an inherited cause of platelet disorders. How does this affect platelet function?

A
  • leads to Gp1b deficiency
  • Gp1b binds to Von Willebrands factor
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16
Q

What is haemophilia?

A
  • genetic disorder
  • affects bodies ability to make blood clots
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17
Q

What is the most common inherited blood coagulation abnormality?

A
  • haemophilia
  • BUT generally not that common
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18
Q

Haemophilia A (which is the more common form) Haemophilia B are the 2 most common inherited blood clotting abnormality. What factors are affected in each?

A
  • Haemophilia A = Factor VIII (8) deficiency
  • Haemophilia B = Factor IX (9) deficiency
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19
Q

What does X linked recessive mean?

A
  • a mutation in a gene on the X chromosome that will always causes the phenotype to be always expressed in males
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20
Q

Are men and women equally affected by haemophilia?

A
  • no
  • women can only be carriers
  • if men have one gene they have disease
  • men cannot transmit disease
21
Q

What are some of the common presenting symptoms of haemophilia?

A
  • spontaneous bleeding into joints and muscles
  • joint disease
  • famility history 1:3 chance
22
Q

The activated partial thromboplastin time (APTT) is a test to determine clotting pathways. What aspects of the clotting cascade can the APTT test assess?

A
  • intrinsic pathway
  • used to assess heparin efficacy
23
Q

The prothrombin time (PT) is a test to determine clotting pathways. What aspects of the clotting cascade can the PT test assess?

A
  • extrinsic pathways
  • important with epithelial surfaces due to tissue factor
  • used to assess the efficacy of warfarin
24
Q

What is does the international normalised ratio (INR) mean in clotting function?

A
  • patients prothrombin time (PT) is compared with normal (PT)
25
Q

What is the thrombin time (TT) test?

A
  • measures of the time taken for a clot to form in the plasma of a blood sample containing anticoagulant, after an excess of thrombin has been added
26
Q

What is bleeding time?

A
  • patient has a superficial cut
  • time taken for bleeding to stop
27
Q

In a patient with haemophilia they are likley to have a prolonged activated partial thromboplastin time (APTT), generally what factors from the coagulation cascade cause this?

A
  • factors VIII (8), IX (9), XI (11) and XII (12)
  • haemophilia A and B are affected factors 8 and 9, respectively
  • all from intrinsic pathway
28
Q

In a patient with haemophilia they are likley to have a normal prothrombin time (PT), why is this?

A
  • haemophilia is caused by dysfunctional factors VIII (8) and IX (9)
  • prothrombin time (PT) does not measure this
29
Q

In haemophilia disease, do all patients have the same levels of factors VIII (8) and IX (9)?

A
  • no
  • severe haemophilia = <1%
  • moderate haemophilia = 1-5%
  • mild haemophilia = >5%
30
Q

How is haemophilia generally treated?

A
  • recombinant DNA used to create factors VIII (8) and IX (9)
  • replace missing factors
31
Q

What is the Von Willebrand Disease?

A
  • common genetic condition that impairs blood clotting
  • Von Willebrand factor helps blood cells stick together (clot) when you bleed.
32
Q

What is the most common blood clotting abnormality?

A
  • Von Willebrand disease (VWD)
33
Q

What does autosomal dominant mean?

A
  • only one form of mutated gene is required to cause disease
34
Q

What are the 2 main roles of the Von Willebrand factor?

A

1 - binds platelets to subendothelial collagen

2 - carries VIII in the plasma

35
Q

How can Von Willebrand disease present?

A
  • Mucocutaneous bleeds
  • nosebleeds
  • menorrhagia
36
Q

In Von Willebrand disease what can we expect to see in the activated partial thromboplastin time (APTT = intrinsic) and prothrombin time (PT = extrinsic)?

A
  • prolonged APTT due to VIII
  • normal PT
37
Q

In Von Willebrand disease what can we expect to see in regards to platelets?

A
  • normal or low platelet number
  • defective platelet function
38
Q

How can we treat Von Willebrand disease?

A
  • Desmopressin (DDAVP) = increases synthesis/release
  • Anti-fibrinolytics (eg Tranexamic acid) = reduce thrombus breakdown
  • Plasma products need to be replaced vWF and Factor VIII
39
Q

What is the most common acquired coagulation disorders?

A
  • chronic liver disease
  • synthesis of clotting proteins is reduced
40
Q

Which factors in the coagulation cascade are dependent on vitamin K?

A
  • 1972 was the diSCo era
  • factors 2, 7, 9 and 10
  • proteins S and C
41
Q

Vitamin K is an important fat soluble vitamin which most people consume enough of. Even if a patient is consuming sufficient vitamin K, what can cause you to have low levels?

A
  • fat malabsorption as vit K is fat soluble
  • biliary obstruction means no bile to digest fat
42
Q

What is Disseminated Intravascular Coagulation (DIC)?

A
  • disease that causes abnormal blood clotting
  • clotting becomes over active
43
Q

What is the most common cause of Disseminated Intravascular Coagulation (DIC)?

A
  • scepticaemia (blood infection)
44
Q

In addition to septicaemia, what other diseases can cause Disseminated Intravascular Coagulation (DIC)?

A
  • Acute promyelocytic leukaemia
  • Cancer, Trauma
  • Pregnancy complication
45
Q

What is the most common trigger that sets off Disseminated Intravascular Coagulation (DIC)?

A
  • increased tissue factor (TF)
  • TF triggers clotting factors
46
Q

In Disseminated Intravascular Coagulation (DIC) what would we expect to see in activated partial thromboplastin time (APTT) and prothrombin time (PT)?

A
  • both would be prolonged
47
Q

In Disseminated Intravascular Coagulation (DIC) what would we expect to see in figrinogen and platelet numbers?

A
  • both would be low
48
Q

In Disseminated Intravascular Coagulation (DIC) what would we expect to see in a d-dimer test?

A
  • d-dimer is a breakdown product of blood clots
  • this would be increased in DIC
49
Q

How can we treat Disseminated Intravascular Coagulation (DIC)?

A
  • treat the underlying cause (antibiotics for septicaemia)
  • treat with coagulation factors