Bleeding Disorders Flashcards
What are the three categories of platelet plug failure?
- vascular (collagen deficiency)
- platelets
- Von Willebrand Factor
Name the vascular causes of platelet plug failure
Hereditary - marfans
Vasculitis - HSP
Ageing - loss of collagen - senile purpura
Vitamin C deficiency
Name the causes of thrombocytopenia
Hereditary - rare
Reduced production - pancytopenia due to marrow failure
Increased destruction
What can cause peripheral platelet destruction?
Coagulopathy e.g DIC
Autoimmune e.g immune thrombocytopenic purpura
Hypersplenism
Describe immune thrombocytopenic purpura
Antibodies against platelets (<1 day life span)
What can cause hypersplenism?
Liver disease and portal hypertension leads to trapping of platelets
Name the functional defects that can increase destruction of platelets
Drugs - aspirin, NSAIDs
Renal failure
How can vWF deficiency arise?
Acquired in autoimmune
Hereditary - autosomal dominant, variable severity
What can cause failure of fibrin clot?
Multiple clotting factor deficiencies
Single clotting factor deficiency
Name the causes of multiple clotting factor deficiencies
Liver disease
Vitamin K deficiency/Warfarin
Complex coagulopathy
Which clotting factors will be reduced in vitamin K deficiency?
II, VII, IX, X
What will PT and APTT be when there are multiple clotting factor deficiencies?
Prolonged
Where are clotting factors made?
Hepatocytes in the liver
What is the function of vitamin K?
Carboxylates factors II, VII, IX and X which is essential for their function
How do we get vitamin K into the blood stream?
Diet and bowel bacteria produce it
Absorbed by upper intestine and requires bile salts
What can cause vitamin K deficiency?
Diet
Malabsorption - Crohn’s
Obstructive jaundice due to lack of bile salts (pancreatic cancer/gallstones)
Warfarin
Haemorrhage disease of the newborn (no bowel bacteria or presence in diet)
How is haemorrhage disease of the newborn prevented?
IM vitamin K
What is DIC?
Disseminated intravascular coagulation
Excessive and inappropriate activation of haemostatic system causing microvascular thrombus formation and end organ failure
How does DIC present?
Clotting factor consumption - fibrinolysis causing bruising, purpura, bleeding
Significantly raised APTT and PT
Really low fibrinogen
What can cause DIC?
Sepsis
Obstetric emergency
Malignancy
Hypovolaemic shock
How is DIC treated?
Manage underlying cause
Replacement therapy - transfusion
How will platelet failure present?
Purpura in lower limbs, mucosal bleeding, retinal haemorrhages
What mode of inheritance is haemophilia?
X linked
What are the two types of haemophilia?
A - factor VIII deficiency
B - factor IX deficiency
Describe haemophilia
Abnormally prolonged bleeding recurs episodically at one or a few sites on each occasion
Which joints are typically affected in haemophilia?
Load bearing - ankles and knees
What will PT and APTT be in haemophilia?
PT normal
APTT prolonged
Name the clinical features of haemophilia
Recurrent haemarthroses
Recurrent soft tissue bleeds - bruising in kids
Prolonged bleeding after dental extraction/surgery/invasive procedures
How does a ‘target joint’ develop?
Iron deposition, inflammation and neovascularisation can eventually lead to joint fusion
How is haemophilia managed?
Replacement of clotting factors by IV injection every couple of days
