AKT Blood Flashcards
Hereditary haemorrhagic telangiectasia and collagen abnormalities such as Ehlers-Danlos syndrome are classified as what type of bleeding disorders?
These are inherited disorders of the blood vessels. Problems with connective tissue can result in friable blood vessels.
What three acquired conditions can lead to friable blood vessels?
Aging
Scurvy
Steroid treatment (Cushing’s)
This type of hereditary bleeding disorder is autosomal dominant, and is characterised by dilated microvascular swellings in the skin, mucous membranes, and internal organs. Results in nose bleeds, GI bleeds, and possibly shunting between the arteries and veins
Hereditary hemorraghic telangectasia (aka Osler-Weber-Rendu syndrome)
Bleeding symptoms tend to occur when platelet levels drop below _______
10
Platelet disorders tend to cause problems with __________ bleeding (skin, nose GI tract, GU tract, menorraghia)
superficial
What are some common causes of platelet disorders?
Bone marrow disorders
ITP
Drug-related
DIC
This self-limiting bleeding condition can follow an infection in children. It tends to be more chronic in adults, but can be treated with Prednisolone or IV immunglobulins
Immune thrombocytopenic purpura
What two substances allow platelets to stick to exposed collagen?
VWF and glycoprotein 1b
Which glycoprotein (along with fibrinogen) binds multiple platelets together?
2b/3a
What substances are released by activated platelets that lead to further platelet activation, as well as adhesion and aggregation?
Thromboxane and ADP
ADP binds to which receptor on platelets?
P2Y12 receptor
What is the role of cycloxygenase (enzyme found within platelets?)
It converts arachadonic acid into thromboxane A2 (substance which promotes further activation of platelets)
Which drug blocks the P2Y12 receptor on platelets?
Clopidogrel
Which glycoprotein is deficient in Glanzmann’s thrombocytopenia?
Gp 2b/3a
Which glycoprotein is deficient in Bernard-Soulier syndrome?
Gp 1b (remember “1Bernard”)
Which are the two most important clotting factors in hemophilia?
8 and 9
What is the most common inherited blood clotting abnormality?
Von Willebrand’s disease
Characteristic clinical sign of haemophilia?
Spontaneous bleeding into joints and muscle
Pattern of inheritance in haemophilia?
X linked recessive (affects males only, females are carriers)
If a man with haemophilia has children with a genetically normal woman, what will the inheritance pattern be for their children?
All daughters of affected men become carriers. The sons are normal.
If a genetically normal man has children with a woman who carries a gene for haemophilia, what will the inheritance pattern be for their children?
Carrier mums have 50% haemophiliac sons and 50% carrier daughters
aPTT is often used in hospitals to measure the efficacy of which drug?
Heparin (mainly testing instrinsic pathway)
PT test measures the efficacy of which drug?
Warfarin (mainly testing the extrinsic pathway)
What does INR measure?
The ratio of the patient’s PT time/normal PT time
What would blood results (lab testing) show in haemophilia?
aPTT would be prolonged
What is the treatment for haemophilia?
Infusions of recombinant factor 8 or 9 every 2-3 days
Inheritance pattern in VonWillebrand’s disease?
Autosomal dominant
Which clotting factor does Von Willebrand’s factor carry through the blood?
Factor 8
How does von willebrand’s disease present?
Deficiency in VWF is a disorder mainly affecting platelets, so it tends to present more like a thrombocytopenia with superficial bleeding. More common in females
Blood results in von willebrand disease?
Prolonged aPTT (remember low factor 8) Normal PT Normal or low platelet numbers Defective platelet function Prolonged bleeding time
Which drug increases the synthesis and release of von willebrand factor?
Desmopressin (ADH analouge)
What is Tranexamic acid used for?
Anti-fibrinolytic most often used by surgeons for patients who won’t stop bleeding post-op. Can also be used to treat von willebrand’s disease
What is the MCC of acquired coagulation disorders?
Liver disease (cirrhosis)
In which life-threatening condition does both bleeding and coagulation tend to occur?
DIC
List the vitamin K dependant clotting factors (and proteins)
2, 7, 9, and 10, as well as Proteins S and C
1972 was the diSCo era
In what conditions might people have a deficiency of Vitamin K?
Fat malabsorption
Biliary obstruction
Hemorrhagic disease of the newborn