12.4 Bleeding Disorders

Question 1

Primary vs secondary haemostasis?

Answer 1

Primary: Formation of platelet plug
Secondary: activation of coag cascade

Question 2

What kind of haemostasis disorder is thrombocytopenia? Why?

Answer 2

Primary; platelet disorder

Question 3

Give some example causes of primary haemostasis disorders

Answer 3

• Medications
• Von Willebrand disease (low levels of vWF)
• Platelet disorders

Question 4

Describe some clinical features of primary haemostasis disorders

Answer 4

• Excessive bleeding
• Epistaxis
• Gum bleeding
• Petechial rash

Question 5

List three hereditary secondary haemostasis disorders

Answer 5

• Haemophilia A
• Haemophilia B
• Rare factor deficiencies (i.e. Factor VII deficiency)

Question 6

List three types of drugs that can cause secondary haemostasis disorders

Answer 6

• Heparins
• Factor Xa inhibitors
• Warfarin

Question 7

What is the most common manifestation of secondary haemostasis disorder? Provide some examples of this

Answer 7

• Most common is internal bleeding
• For example: joint bleeds, muscular bleeds, intracerebral haemorrhage

Question 8

What does DIC stand for in terms of bleeding disorders?

Answer 8

Disseminated intravascular coagulopathy

Question 9

List some factors that can cause hyperfibrinolysis

Answer 9

• Prostate carcinoma
• Peripartum complications
• Fibrinolytic treatment

Question 10

Describe the pathogenesis of disseminated intravascular coagulation

Answer 10

Coagulation pathways become abnormally (often massively) activated, leading to overt thrombotic complications.

In addition, clotting factors are consumed at a high rate, and so this can increase bleeding risk.

Question 11

What are some areas of the body harmed by the overt thrombotic complications that can arise from Disseminated Intravascular Coagulopathy (DIC)

Answer 11

• Brain: Confusion, sedation
• Kidneys: reduced urine output
• Lung: Hypoxia, haemoptysis
• Liver: Jaundice

Question 12

DIC causes overactivation of thrombotic pathways, so how can it lead to uncontrolled bleeding?

Answer 12

Overconsumption of clotting factors and platelets.

Question 13

Describe the pathogenesis of immune thrombocytopenic purpura

Answer 13

• Autoantibodies against platelets, leading to platelet destruction
• Causes release of blood under skin, and thus purpura

Question 14

Chronic renal failure can cause abnormal platelet function. Why?

Answer 14

Nobody knows. It’s a mystery.

Question 15

How do lymphoma and multiple myeloma cause bleeding disorders?

Answer 15

• Cause thrombocytopenia and increased blood viscosity by crowding out bone marrow
• Leads to inability to form clots properly

Question 16

List some medications that can cause bleeding disorders

Answer 16

• Anticoagulants
• Fibrinolytics
• Aspirin
• NSAIDs

Question 17

Which clotting factor is deficient in Haemophilia A vs B?

Answer 17

A: Factor VIII
B: Factor IX

Question 18

Describe the genetic transmission of Haemophilia A and B

Answer 18

X-Linked recessive

Question 19

What are the two main roles of von Willebrand Factor?

Answer 19

• Protect Factor VIII from degranulation
• Promote platelet adhesion

Question 20

Describe the genetic transmission of von Willebrand disease. What is the exception?

Answer 20

Autosomal dominant; except type 3, which is autosomal recessive

Question 21

Which types of von Willebrand disease are caused by qualitative vs quantitative defects in vWF?

Answer 21

Quantitative: Type 1 and 3
Qualitative: Types 2B, 2A, and 2M (BAM)

Question 22

What is the time before onset in primary/secondary haemostasis disorders vs disseminated intravascular coagulation?

Answer 22

Primary: Immeditately after insult/trauma
Secondary: Delayed by minutes/hours
DIC: Varies based on cause