Coagulopathies

Question 1

What are coagulopathies

Answer 1

Diseases in which there is an abnormal coagulation cascade

Question 2

What are the three main coagulopathies

Answer 2

Hemophilia
Vitamin K deficiency

Question 3

Test of platelet function
Small cut to patient’s arm
Filter paper applied and removed at regular intervals until bleeding stops
Rarely done in modern era
What is this done to test

Answer 3

Bleeding time

Question 4

Test of platelet function
Small cut to patient’s arm
Filter paper applied and removed at regular intervals until bleeding stops
Rarely done in modern era
What is this done to test

Answer 4

Bleeding time

Question 5

Which test tests the intrinsic pathway of activating the coagulation cascade

Answer 5

Activated partial thromboplastin time

Question 6

How is PTT done

Answer 6

Add plasma to (-) charge substance (silica). Silica activates factor 12 to initiate the intrinsic pathway. Record time it takes for blood to clot. Normal is about 30s

Question 7

What test is the test of the extrinsic pathway

Answer 7

Prothrombin time

Question 8

How is PT done

Answer 8

Add plasma you want to assess, add tissue factor. Tissue factor then initiates the extrinsic pathway and you measure the time it takes for a fibrin to clot to form. Normal is about 10s

Most labs convert the PT to an INR (international normalized ratio). INR = Patient’s PT/Control PT. Normal is 1 and therapeutic on coumadin for example is about 2-3

Question 9

How is thrombin time performed

Answer 9

Add thrombin to sample and record the time it takes to clot
Because thrombin is very far down the cascade, the only way this test would be and normal is if there is an inhibitor of thrombin in the plasma or if the patient has a very low fibrinogen level

Question 10

What is the characteristic finding when bleeding is as a result of abnormal platelets

Answer 10

Petechiae on the skin

Question 11

Bleeding caused by abnormal platelets present with

Answer 11

Mucosal bleeding
Skin bleeding
Petechiae

Question 12

Bleeding due to abnormal coagulation factors presents with

Answer 12

Joint bleeding, deep tissue bleeding
(Bleeding as a result of abnormal coagulation factors tend to be deeper)

Question 13

X-linked recessive diseases
Gene mutations: Run in families, also occur de novo
Also called Christmas disease
What condition could I be

Answer 13

Hemophilia B

Question 14

Which hemophilia is caused by a deficiency in factor VIII

Answer 14

Hemophilia A

Question 15

Which hemophilia is caused by a deficiency in factor IX

Answer 15

Hemophilia B

Question 16

What type of hemophilia is less common

Answer 16

Hemophilia B

Question 17

What is the most common presentation of hemophilia

Answer 17

Joint bleeds

Question 18

What are the presentations of hemophilia

Answer 18

Spontaneous or easy bruising
Recurrent joint bleeds

Question 19

What is the screening for hemophilia

Answer 19

PTT will be prolonged because factors 8 and 9 are both part of the intrinsic pathway
PT, bleeding time, platelet count are all normal

Question 20

How is hemophilia treated

Answer 20

Replacement factor 8 and 9
Desmopressin (dDAVP) - used in mild hemophilia A, analogue of vasopressin with no press or activity, increases vWF and factors 8 levels, releases VIII from Weibel-Palade bodies (endothelial cells), also has vasodilating properties
Aminocaproic acid- antifibrinolytic drug, inhibits plasminogen activation to plasmin thus there’s less breakdown of formed clots allowing factors 8 and 9 to work more effectively because plasmin is not breaking down whatever fibrin clots can be formed
Cryoprecipitate

Question 21

What bodies are vWF and factor 8 stored in

Answer 21

Weibel-Palade bodies

Question 22

Besides treating hemophilia, what are some other uses of the drug desmopressin

Answer 22

Treating:
von Wilebrand disease
Central diabetes insipidus (mimics ADH)
Bed wetting (decrease urine volume)

Question 23

What are the key side effects of desmopressin

Answer 23

Flushing and headache

Question 24

Obsolete therapy for hemophilia A
Precipitate that forms when fresh frozen plasma is thawed and is separated from plasma by centrifugation
Contains lots of factor 8 and fibrinogen
Also contains some factor 13 and vWF
Often used as a source of fibrinogen
Used in conditions like DIC and massive trauma with blood transfusions
What therapy could this be

Answer 24

Cryoprecipitate

Question 25

What study differentiates hemophilia A from bleeding caused by coagulation factor inhibitors

Answer 25

Mixing study

Question 26

Antibodies that are directed against the clotting factor
Inhibit activity or increase clearance of clotting factor
Inhibitors of factor 8 most common
Often occurs in association with some disorders
Can be treated with prednisone as an immunosuppressant
What could this be

Answer 26

Clotting factor inhibitors

Question 27

What conditions are associated with clotting factor inhibitors

Answer 27

Malignancy
Post-partum
Autoimmune disorders

Question 28

Presentations of coagulation factor inhibitors and hemophilia can be similar
True or false

Answer 28

True

Question 29

What principle is a mixing study based on

Answer 29

When clotting factors are 50% of normal, you will get a normal PT or PTT level

Question 30

Results in bleeding
Deficiency of vitamin-K dependent factors 2, 7, 9 and 10
What condition might this be

Answer 30

Vitamin K deficiency

Question 31

What are the key lab findings in a vitamin K deficiency

Answer 31

Elevated PT/INR(because factor 7 of the extrinsic pathway will be the first to decrease or fall)
Can see elevated PTT (less sensitive)
Normal bleeding time

Question 32

Which factor level would be the first to fall in a vitamin K deficiency due its relatively shorter half-life

Answer 32

Factor 7

Question 33

Why is a dietary deficiency of vitamin K very rare

Answer 33

GI bacteria produce sufficient quantities of vitamin K

Question 34

What are some common causes of vitamin K deficiency

Answer 34

Warfarin
Antibiotics (deplete GI bacteria)
Newborns (sterile GI tract)
Malabsorption (Vitamin K is fat soluble)

Question 35

What is another potential cause for coagulopathies
Often treated with fresh frozen plasma (plasma which contains all clotting factors)

Answer 35

Blood transfusion