Flashcards in MHD: Clinical approach to bleeding patient Deck (14):
What can we learn from a CBC with differential lab?
Look for involvement of other cell lines
Evidence of systemic disorder
What can we learn from PT and aPTT?
Are there abnormalities in coagulation system?
Will detect qualitiative AND quantitative disorders, but not differentiate the two
May differentiate which factor is culprit
What can we learn from a bleeding time test?
Gives info about platelet activation, but not used anymore today
Prolonged bleeding time with a normal platelet count suggests what type of disorder
Qualitative disorder: inherited (Glanzmann, Bernard-Soulier, storage pool disease, VWD)
Which receptors are affected in Glanzmann, Bernard-Soulier disorders?
Gp1b in BS
GpIIbIIIa in Glanzman
If VWD is suspected, what lab studies can be done to confirm the suspicion?
VWF antigen to see if patient has any VWF
vWF:ristocetin activity to see if VWF works
FVIII clotting activity to see if VIII is affected
VW multimers looks at VWF structure
How are factor VIII levels related to VWD?
VWF is a carrier for FVIII, so in the absence of VWF, the half life of FVIII is decreased and levels will be lower than normal
What lab tests differentiated hemophilia A from VWD?
Ristocetin activity: normal in HemA, low in VWD
vWF:Ag: normal in HemA, low/normal in VWD
What causes a prolonged PT?
Factor VII deficiency
What causes a prolonged PTT?
Deficiency/inhibition of VIII, IX, XI, XII
What causes both a prolonged PT and PTT?
Heparin/Warfarin high doses
Vit K deficiency
What is the utility of a mixing study?
To differentiate between a clotting factor deficiency and an inhibitor of the clotting factor function
Mix patient plasma with normal plasma, will clot if problem was a deficiency, but will not clot if problem was inhibitor
What are the most common inherited coagulation defects?
X-linked: Hemophilia A (VIII) and Hemophilia B (IX)