Hemostasis Defects Flashcards Preview

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Flashcards in Hemostasis Defects Deck (66)
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1

What factors does protime (PT) measure?

II, VII, X, V and fibrinogen

The extrinsic and lower part of the coagulation cascade.

2

What is a normal PT?

9-12 seconds

3

Because the PT is dependent upon the potency of the material that i used to start the reaction in the laboratory what must it be compare to?

International normalized ration (INR)

4

What is a normal INR?

1.0

5

What are two of the most common causes of abnormal PT?

Deficiency of vitamin K dependent factors (VII, X, II) or

Inadequate liver funciton

6

What would warfarin do to the PT?

Increase PT

7

What does the PTT measure?

The procoagulant activity of the entire pathway, but it is more sensitive to deficiencies of the higher numbered factors especially XI, VIII, and IX

8

What is PTT not effective in measuring?

Factor VII

9

What can prolong the PTT?

Heparin or acquired anticoagulants such as fibrin split products

Patients with hemophilia

10

What is a normal PTT?

25-32 seconds

11

What is PT used to monitor?

What is PTT used to monitor?

-Warfarin

-Heparin

12

What does thrombin time measure?

The procoagulant activity of fibrinogen and is also very sensitive to the anticoagulant effect of heparin or fibin split products.

13

What is the normal range of thrombin time?

12-18 seconds

14

What does the bleeding time measure?

Platelet and vessel initeraction as well as the number and the function of platelets.

15

What is a normal bleeding time?

2-9 minutes

16

What will cause an increase in bleeding time?

Severe decrease in platelet count

von Willebrand disease

abnormalit in platelet function

OTHER FACTOR DEFICIENCIES DO NOT PROLONG THE BLEEDING TIME

17

What is PFA-100?

Platelet function analyzer that can perform an in vitro bleeding time

18

What is most common cause of a severe bleeding tendency?

Hemophilia A (Factor VIII deficiency)

19

Hemophilia B is characterized as a deficiency of what coagulation factor?

Factor iX

20

What is the inheritance pattern of both Hemophilia A and Hemophilia B?

X-Linked
Females are carriers
Men are affected

21

Which test is prolonged in Hemophilia A and B?

PTT

22

What is the genetic defect is seen in 40% of Hemophilia A patients?

Inversion on the long arm of the X chromosome

23

Less than 1% factor activity is considered a severe hemophilia. What are the symptoms of someone with less than 1% factor activity?

Spontaneous hemorrhaging into their joints, muscles, soft tissues, retroperitoneal space and CNS.

Continuous bleeding into the joints leads to very severe arthritis

24

Between 2%-5% factor activity is considered to by a moderate hemophilia. What are the symptoms of someone with moderate hemophilia?

It usually takes some degree of trauma to cause bleeding in these patients

25

>10% factor activity is considered a mild hemophilia. What are the symptoms of someone with >10% factor activity?

Only bleed after trauma and do not develop the chronic joint disease

They are usually diagnosed after a bad traumatic even ot after a bad result from surgery

26

Female carriers can express anywhere from 30-100% factor activity, but at what percent are they symptomatic carriers?

30%

27

Factor XI deficiency usually express >5% factor activity. Are they spontaneous bleeders?

No usually

28

What is the inheritance pattern of Factor XI deficiency?

Autosomal recessive

29

What patient population is Factor XI deficiency common in?

Ashkenazi Jews

30

What test time is usually prolonged in Factor XI deficiency?

PTT