Hemostasis Defects

Question 1

Intrinsic pathway deficiencies lengthen the _______.

Answer 1

PTT (partial thromboplastin time)

Question 2

aPTT tests all of the factors except ______.

Answer 2

VII (it is also sensitive to blood thinners)

Question 3

PT/INR times can be prolonged with deficiencies in ________.

Answer 3

II, VII, V, X, vitamin K, liver functioning, and fibrinogen

Question 4

List the four most common congenital clotting disorders.

Answer 4

Hemophilia A (factor VIII), hemophilia B (factor IX), hemophilia C (factor XI), and von Willebrand disease

Question 5

In the x-linked hemophilias (which are ______), carrier females are often _____.

Answer 5

A and B; symptomatic

Question 6

In hemophilia C, bleeding occurs in areas of fibrinolysis such as ________.

Answer 6

the prostate, bladder, or uterus

Question 7

Thombin time (TT) tests the _________ activity.

Answer 7

fibrinogen

Question 8

Prothrombin time (PT) tests the ________.

Answer 8

extrinsic pathway as well as the common pathway (Xa, Va, IIa)

Question 9

PT is used to monitor ______ therapy.

Answer 9

warfarin, because PT tests all of the vitamin-K dependent serine proteases

Question 10

Normal PTT range is ________.

Answer 10

25 - 32 seconds

Question 11

Thrombin time detects ______ deficiency.

Answer 11

fibrinogen

Question 12

PFA-100 tests the __________.

Answer 12

platelet function (platelet function analyzer)

Question 13

The most common bleeding disorders are ___________.

Answer 13

hemophilia A (VIII deficiency), hemophilia B (IX deficiency), and von Willebrand disease

Question 14

Hemophilia A and hemophilia B cause ________ clinical presentations.

Answer 14

identical (specific factor assays must be done to distinguish the two, although A is 10x more common)

Question 15

Genetically, both hemophilia A and B are _________.

Answer 15

X-linked recessive

Question 16

The minimum clotting ability needed for surgery is _______.

Answer 16

50%

Question 17

In factor VII deficiency, only the ______ is prolonged.

Answer 17

PT

Question 18

vWF is important for __________.

Answer 18

adhering platelets to collagen and carrying VIII

Question 19

von Willebrand disease results in _________.

Answer 19

mild bleeding disorders

Question 20

Lab tests for vWD will show _________.

Answer 20

increased PTT and bleeding times

Question 21

Type I vWD is _______, while type II is ________; type III is _________.

Answer 21

deficient vWF; defective vWF; total absence

Question 22

Arginine vasopressin is only effective in type ______ vWD.

Answer 22

I

Question 23

Aggregating to ristocetin tests for ________.

Answer 23

type II vWD

Question 24

Liver disease tests will show __________.

Answer 24

PT > PTT, but both prolonged (note, vitamin K deficiency and warfarin can also cause this)

Question 25

Describe antiphospholipid syndrome.

Answer 25

Patients develop an antibody to phospholipids that prolongs the PTT but actually lead to an increased tendency to clot

Question 26

What is the Russell Viper Venom Test?

Answer 26

You add viper venom and phospholipid to a sample of patient plasma. The venom activates X, but if a patient has antiphospholipid antibody, then the PTT will not correct. Adding more antibody will correct the time.

Question 27

If PTT is longer than PT, but both are prolonged, think of _________.

Answer 27

DIC

Question 28

If you do a 1:1 mixture of patient plasma with normal plasma and the PTT does not correct, then the diagnosis is likely ________.

Answer 28

lupus antcoagulant

Question 29

If the 1:1 correction does not stay corrected at two hours, then the diagnosis is likely ________.

Answer 29

factor VIII inhibitor