Thrombotic Disease & Placental Disorders

Question 1

define haemostasis

Answer 1

balance between coagulation and haemorrhage

Question 2

what is the breakdown of a clot called?

Answer 2

Fibrinolysis

Question 3

Where are platelets produced and what cells produce them?

Answer 3

produced in bone marrow by megakaryocytes

Question 4

what is in the buffy coat?

Answer 4

leukocytes and platelets

Question 5

platelet lifespan?

Answer 5

10 days

Question 6

what does vascular injury near sub epithelium cause?

Answer 6

direct activation of glycoprotein factors (collagen) and indirect via von Willebrand factor which attract platelets

Question 7

what chemical do attracted platelets release and what does this cause?

Answer 7

thromboxane A2 (prostaglandin) released which attracts more platelets

Question 8

what factors prevent platelet activation and when are these higher?

Answer 8

prostacyclin and nitrous oxide, higher in preg

Question 9

define the intrinsic pathway

Answer 9

activated as direct result of blood vessel damage by tissue factor contacting clot producing proteins

Question 10

describe extrinsic pathway

Answer 10

activated due to organ damage, hypoxia, sepsis, malignancy and inflammation

Question 11

what is both intrinsic and extrinsic common pathway initiated by?

Answer 11

factor XA (10A)

Question 12

how many molecules of thrombin activated from one factor XA molecule?

Answer 12

1000 molecules of thrombin

Question 13

what does expansion of blood vol and change in haemostatic system in normal pregnancy cause?

Answer 13

hypercoagulability and hypofibrinolysis (reduced degradation of clot)

Question 14

when is von Willebrand factor upregulated?

Answer 14

in pregnancy and after pregnancy (reduce PPH)

Question 15

where is tissue factor produced and expressed?

Answer 15

produced on endothelial cells, placenta and decidua, expressed in STB

Question 16

what is tissue factor essential for?

Answer 16

implantation, embryogenesis, angiogenesis

Question 17

list pregnancy factors that increase the risk of thrombosis

Answer 17

increase venous distension, decreased venous outflow, mechanical obstruction by uterus, decreased mobility, vascular injury

Question 18

how much is thrombosis increased in preg?

Answer 18

4-5 times

Question 19

once a clot has formed and fibrinolysis begins, what is produced as a byproduct?

Answer 19

D dimer

Question 20

what inhibits degradation of a clot?

Answer 20

plasminogen activator inhibitor 1 and 2

Question 21

describe gestational thrombocytopenia

Answer 21

reduced platelets increasing risk of bleeding, bruising and abnormal clotting

Question 22

describe idiopathic thrombocytopenia parpura

Answer 22

Autoimmune disease where immune system attacks and destroys platelets, glucocorticoids used in T3, affects fetus as 5-10% risk of fetal thrombo

Question 23

how many women experience thrombocytopenia in pregnancy?

Answer 23

1/10

Question 24

describe antiphospholipid syndrome and how to diagnose

Answer 24

mat produces antibodies to phospholipids, diagnosed after med-high levels of antibodies on 2-3 occasions, increases clots

Question 25

what outcomes increase with placenta accreta?

Answer 25

thrombosis and APH/PPH

Question 26

define placental abruption

Answer 26

complete or partial separation of placenta before birth

Question 27

CS or VE after placental abruption?

Answer 27

VE associated with less blood loss

Question 28

outline the coagulation cycle

Answer 28

haemorrhage -> platelet activation -> clotting cascade -> platelet stabalisation -> fibrinolysis

Question 29

what does vascular injury expose to blood and what does this cause?

Answer 29

VWF and collagen exposed to blood -> platelet aggregation

Question 30

what happens to platelets when they initially aggregate at site of injury?

Answer 30

they change shape and release signalling molecules

Question 31

what does thrombin convert fibrinogen into and what is its' function?

Answer 31

fibrin strands which acts as mesh for clot

Question 32

what are the main function of VWF?

Answer 32

platelet adhesion and aggregation

Question 33

how are clots prevented in the umbilical vein?

Answer 33

presence of tissue factor pathway inhibitor

Question 34

list risk factors for thrombosis (aquired and genetic)

Answer 34

advanced mat age, lupus, sickle cell, smoking, obesity, heart disease, factor V Leiden mutation, prothrombin mutation, protein C/S deficiency

Question 35

outline PE effects on fibrin and BVs

Answer 35

increased fibrin deposition and impaired fibrinolysis, increased vasoconstriction

Question 36

how does GDM increase risk of thrombosis

Answer 36

high BGL causes endothelial damage which activates the intrinsic coagulation pathway

Question 37

list pregnancy consequences of APS

Answer 37

PE, VTE, rec misc, IUFD, FGR

Question 38

list symptoms of thrombosis

Answer 38

swelling, back pain, dyspnea, chest pain, cough, increased perspiration