L25 - Coagulation and platelets Flashcards
Clinical evaluation of the bleeding patient involves determining if the cause is either a __________ or ________. Give examples for each.
- platelet disorder (thrombocytopenia, qualitative platelet disorders)
- coagulation factor disorder (hemophilia A and B, coag factor inhibitors, von Willebrand disease)
Petechiae, ecchymoses, mucocutaneous bleeding suggest ____?
A. von Willebrand Disease
B. platelet defect
C. coagulation factor defect
B
Hemarthrosis, hematuria, deep hematoma suggest
A. von Willebrand Disease
B. platelet defect
C. coagulation factor defect
C
Presence of both types of bleeding suggests
A
Which medication does not have a side effect of bleeding? Al. heparin B. Warfarin C. rivaroxaban D. Aspirin E. Clopidogrel F. dabigatran G. apixaban H. Tylenol
H
Which lab tests assess platelets?
- Platelet count
2. Platelet function (PFA-100, platelet aggregation testing, thromboelastography)
Which is false regarding platelet count?
A. Normal range: 150,000 to 450,000/µL
B. In the absence of qualitative platelet dysfunction >100,000/uL has possible increased risk of bleeding with major trauma or surgery
C. In the absence of qualitative platelet dysfunction
B. there is no increased risk of bleeding, this is for values 50,000-100,000uL
Also, increased risk of bleeding with minor trauma or surgery
for 5,000-50,000
system for analysing platelet function in which citrated whole blood is aspirated at high shear rates through disposable cartridges containing an aperture within a membrane coated with either collagen and epinephrine (CEPI) or collagen and ADP (CADP)
PFA-100
PFA-100 measures the time required for the platelets in a sample of blood to plug a small hole in a tiny tube after being exposed to various activating substances. This is called the _______. If prolonged, this indicates ____ platelet function but do not identify the cause
- closure time
2. lower
- Which lab tests assess coagulation (3)?
2. which factors or parts of the coagulation cascade do they test?
- Prothrombin time (PT) - 7
- Activated partial thromboplastin time (APTT) - 8, 9
- Thrombin time (TT) - thrombin
liver disease, vitamin K deficiency, or warfarin prolong which of the following?
A. TT
B. PT
C. APTT
B
• Prothrombin time (PT)
• Most sensitive to Factor VII
• Prolonged by liver disease, vitamin K deficiency, or warfarin
• Often reported as INR (International Normalized Ratio)
hemophilia, coagulation factor inhibitors, or heparin prolong which of the following? A. TT B. PT C. APTT
C
• Activated partial thromboplastin time (APTT)
• Sensitive to Factors VIII and IX
Prolonged by hemophilia, coagulation factor inhibitors, or heparin
direct thrombin inhibitors prolong which of the following?
A. TT
B. PT
C. APTT
A
• Thrombin time (TT)
• Prolonged by direct thrombin inhibitors (too sensitive)
Low fibrinogen
1:1 mix corrects to normal
A. coagulation factor deficiency
B. coagulation factor inhibitor
A. coagulation factor deficiency
clotting tests give normal values when 50% activity of the involved coagulation factors is present. A 1:1 mix will reduce the activity of all the factors in normal pooled plasma to 50 percent.
• Thus, if the clotting test returns to normal after a 1:1 mix with normal pooled plasma, a factor deficiency was the cause of the abnormal test.
1:1 mix does not correct to normal
A. coagulation factor deficiency
B. coagulation factor inhibitor
B. coagulation factor inhibitor
- Most agents that inhibit clotting factor activity (such as antibodies) will not be effectively diluted out after addition of an equal volume of normal pooled plasma.
- Thus, if the test remains abnormal after 1:1 dilution, an inhibitor was the cause of the abnormal test
Platelet count less than 150,000/ul
Thrombocytopenia
