Bleeding disorders Flashcards
What are the 3 reasons for abnormal bleeding?
Vascular disorder, Thrombocytopenia (defective platelet function) and defective coagulation
In coagulation disorders, where does bleeding occur?
Into the joints or soft tissue
In vascular and platelet disorders, where does bleeding take place?
From the mucous membranes and skin
What are the genetic probability for people inheriting bleeding disorders?
In disorders affecting platelets, it is equal in both sexes, while coagulation diseases are X-linked and have occurred in males >80% of the time
What is thrombocytopenia?
The most common platelet disorder and most commonly acquired. Can be due to a failure of production or increased destruction. It is characterised by spontaneous skin purpura, mucosal haemorrhage and prolonged bleeding after trauma
What is platelet function analysis (PFA 100)?
An alternative to bleeding time that has a quick and easy determination of platelet function. Citrated whole blood is aspirated at high shear rates through disposable cartridges containing an aperture coated with either collagen and epinephrine or collagen and ADP
What can be used to prevent atherothrombosis?
Aspirin as it permanently inactivates cyclooxygenase
What are the most common acquired bleeding disorder?
Vitamin K deficiency, liver disease, disseminated intravascular coagulation, massive blood loss, auto-antibodies
What are the most common inherited bleeding disorders?
Hemophilia, Von Willebrand disease, Bernard-Soulier syndrome, Glanzmann’s thrombasthenia
What is our main source of vitamin K and what does it do?
Dark green veg and serves as an essential co-factor for carboxylase that catalyses carboxylation of glutamic acid residues on vitamin K-dependent proteins
What are key vitamin K-dependant proteins?
Coagulation proteins - factor 2, 7, 9 and 10
Anticoagulation proteins - protein C, S and Z (all require carboxylation)
What happens when glutamic has been carboxylated by vitamin K?
Can bind calcium more effectively
What can cause vitamin K deficiency?
Malabsorption of fat-soluble vitamins, oral anticoagulation therapy (warfarin), liver disease, dietary deficiency associated with antibiotic treatment that destroys gut bacteria that can synthesise Vit K
What clotting factors are produced by the liver?
1, 2, 5, 7, 9 10 and some 8
What is disseminated intravascular coagulation (DIC)?
Inappropriate activation of blood coagulation, causing a generation and deposition of fibrin leading to microvascular thrombi in various organs. Disease can be fatal
