12.4 Bleeding Disorders Flashcards
Primary vs secondary haemostasis?
Primary: Formation of platelet plug
Secondary: activation of coag cascade
What kind of haemostasis disorder is thrombocytopenia? Why?
Primary; platelet disorder
Give some example causes of primary haemostasis disorders
- Medications
- Von Willebrand disease (low levels of vWF)
- Platelet disorders
Describe some clinical features of primary haemostasis disorders
- Excessive bleeding
- Epistaxis
- Gum bleeding
- Petechial rash
List three hereditary secondary haemostasis disorders
- Haemophilia A
- Haemophilia B
- Rare factor deficiencies (i.e. Factor VII deficiency)
List three types of drugs that can cause secondary haemostasis disorders
- Heparins
- Factor Xa inhibitors
- Warfarin
What is the most common manifestation of secondary haemostasis disorder? Provide some examples of this
- Most common is internal bleeding
- For example: joint bleeds, muscular bleeds, intracerebral haemorrhage
What does DIC stand for in terms of bleeding disorders?
Disseminated intravascular coagulopathy
List some factors that can cause hyperfibrinolysis
- Prostate carcinoma
- Peripartum complications
- Fibrinolytic treatment
Describe the pathogenesis of disseminated intravascular coagulation
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.
What are some areas of the body harmed by the overt thrombotic complications that can arise from Disseminated Intravascular Coagulopathy (DIC)
- Brain: Confusion, sedation
- Kidneys: reduced urine output
- Lung: Hypoxia, haemoptysis
- Liver: Jaundice
DIC causes overactivation of thrombotic pathways, so how can it lead to uncontrolled bleeding?
Overconsumption of clotting factors and platelets.
Describe the pathogenesis of immune thrombocytopenic purpura
- Autoantibodies against platelets, leading to platelet destruction
- Causes release of blood under skin, and thus purpura
Chronic renal failure can cause abnormal platelet function. Why?
Nobody knows. It’s a mystery.
How do lymphoma and multiple myeloma cause bleeding disorders?
- Cause thrombocytopenia and increased blood viscosity by crowding out bone marrow
- Leads to inability to form clots properly
List some medications that can cause bleeding disorders
- Anticoagulants
- Fibrinolytics
- Aspirin
- NSAIDs
Which clotting factor is deficient in Haemophilia A vs B?
A: Factor VIII
B: Factor IX
Describe the genetic transmission of Haemophilia A and B
X-Linked recessive
What are the two main roles of von Willebrand Factor?
- Protect Factor VIII from degranulation
- Promote platelet adhesion
Describe the genetic transmission of von Willebrand disease. What is the exception?
Autosomal dominant; except type 3, which is autosomal recessive
Which types of von Willebrand disease are caused by qualitative vs quantitative defects in vWF?
Quantitative: Type 1 and 3
Qualitative: Types 2B, 2A, and 2M (BAM)
What is the time before onset in primary/secondary haemostasis disorders vs disseminated intravascular coagulation?
Primary: Immeditately after insult/trauma
Secondary: Delayed by minutes/hours
DIC: Varies based on cause
