Hemostasis Defects Flashcards
Intrinsic pathway deficiencies lengthen the _______.
PTT (partial thromboplastin time)
aPTT tests all of the factors except ______.
VII (it is also sensitive to blood thinners)
PT/INR times can be prolonged with deficiencies in ________.
II, VII, V, X, vitamin K, liver functioning, and fibrinogen
List the four most common congenital clotting disorders.
Hemophilia A (factor VIII), hemophilia B (factor IX), hemophilia C (factor XI), and von Willebrand disease
In the x-linked hemophilias (which are ______), carrier females are often _____.
A and B; symptomatic
In hemophilia C, bleeding occurs in areas of fibrinolysis such as ________.
the prostate, bladder, or uterus
Thombin time (TT) tests the _________ activity.
fibrinogen
Prothrombin time (PT) tests the ________.
extrinsic pathway as well as the common pathway (Xa, Va, IIa)
PT is used to monitor ______ therapy.
warfarin, because PT tests all of the vitamin-K dependent serine proteases
Normal PTT range is ________.
25 - 32 seconds
Thrombin time detects ______ deficiency.
fibrinogen
PFA-100 tests the __________.
platelet function (platelet function analyzer)
The most common bleeding disorders are ___________.
hemophilia A (VIII deficiency), hemophilia B (IX deficiency), and von Willebrand disease
Hemophilia A and hemophilia B cause ________ clinical presentations.
identical (specific factor assays must be done to distinguish the two, although A is 10x more common)
Genetically, both hemophilia A and B are _________.
X-linked recessive
The minimum clotting ability needed for surgery is _______.
50%
In factor VII deficiency, only the ______ is prolonged.
PT
vWF is important for __________.
adhering platelets to collagen and carrying VIII
von Willebrand disease results in _________.
mild bleeding disorders
Lab tests for vWD will show _________.
increased PTT and bleeding times
Type I vWD is _______, while type II is ________; type III is _________.
deficient vWF; defective vWF; total absence
Arginine vasopressin is only effective in type ______ vWD.
I
Aggregating to ristocetin tests for ________.
type II vWD
Liver disease tests will show __________.
PT > PTT, but both prolonged (note, vitamin K deficiency and warfarin can also cause this)
Describe antiphospholipid syndrome.
Patients develop an antibody to phospholipids that prolongs the PTT but actually lead to an increased tendency to clot
What is the Russell Viper Venom Test?
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.
If PTT is longer than PT, but both are prolonged, think of _________.
DIC
If you do a 1:1 mixture of patient plasma with normal plasma and the PTT does not correct, then the diagnosis is likely ________.
lupus antcoagulant
If the 1:1 correction does not stay corrected at two hours, then the diagnosis is likely ________.
factor VIII inhibitor
