Bleeding Disorders Flashcards
In what layer are endothelia cells found?
Tunica intima
What things does formation of the platelet plug involve?
Involves endothelial cells, collagen, subendothelial fibrils, VWF and platelets
Why are women much more likely to present with vWF factor deficiency?
Women are much more likely to present with VWF than men as they have regular periods and menorrhagia whereas men don’t usually present until they have surgery
What can the causes of failure of the platelet plug to form be differentiated into?
- Vascular
- Platelets - reduced number/reduced function
- Von Willebrand Factor
Vascular abnormalities can be either _________ or _________
Hereditary or acquired
Hereditary vascular abnormalties are common
FALSE - they are rare
Give an example of a hereditary vascular abnormality.
Marfan’s
Give examples of acquired vascular abnormalities which can result in failure of formation of the platelet plug.
Henoch-Schonlein Purpura
Children, affecting mucous membranes, purpuric rash on lower limbs, GI bleeding (PR blood), but self-limiting.
Why is age an acquired vascular abnormality that results in failure of the platelet plug to form.
As we age we use collagen
_______ is a vitamin D deficiency seen in alcoholics who eat little fruit
Scurvy
What does scurvy cause?
Acquired vascular abnormality resulting in failure of the platelet plug to form
Outline the main clinical features seen in someone with an acquired vascular abnormality resulting in failure of the platelet plug to form.
Most likely to get a non-blanching purpuric rash on the lower limbs.
May also get bleeding from small vessels in mucous membranes - epistaxis, blood blisters in mouth
Retinal haemorrhages.
What is thrombocytopenia?
LOW platelets
What can thrombocytopenia be classified as?
Can be hereditary or acquired, although acquired is significantly more common
How can acquired thrombocytopenia be classified?
- Reduced production (marrow failure)
or - Increased destruction
What are 3 causes of peripheral platelet destruction?
- Coagulopathy e.g DIC
- Autoimmune
- Hypersplenism
Give example of a coagulopathy which causes peripheral platelet destruction.
Disseminated intravascular coagulation (DIC)
What happens in DIC?
Haemostasis is activated and clotting factors and platelets are used up
What is the most common autoimmune cause of peripheral platelet destruction?
Immune thrombocytopenic purpura (ITP)
What happens in ITP?
Everyone has white blood cells which make things called antibodies which recognise foreign material (things that aren’t meant to be there) in our body
In autoimmune conditions, the antibodies get a bit confused and attack the body’s own cells. Antibodies stick to platelets and cause them to be removed.
What is alcoholics liver disease a common cause of?
Hypersplenism
Why does hypersplenism result in peripheral platelet destruction?
Anything that makes the spleen enlarged will lead to thrombocytopenia as the spleen is responsible for the breakdown of platelets
How does alcoholics liver disease a common cause of hypersplenism?
Alcoholics liver disease causes cirrhosis and scarring of the liver, this leads to varices, back pressure of fluid, portal hypertension and eventually an enlarged spleen - hypersplenism
Platelet functional defects can be _________ or _________
Hereditary or acquired
Suggest acquired causes of platelet functional defects.
Drugs – aspirin, NSAID’s (stop platelets sticking together).
Renal failure – uraemia can lead to problems with platelet function.
How is inherited vWF factor deficiency inherited?
Autosomal dominant
vWF factor deficiency can be _________ or ________
Hereditary or acquired
