MHD: Clinical approach to bleeding patient

Question 1

What can we learn from a CBC with differential lab?

Answer 1

Platelet quantity
Look for involvement of other cell lines
Platelet appearance
Evidence of systemic disorder

Question 2

What can we learn from PT and aPTT?

Answer 2

Are there abnormalities in coagulation system?
Will detect qualitiative AND quantitative disorders, but not differentiate the two
May differentiate which factor is culprit

Question 3

What can we learn from a bleeding time test?

Answer 3

Gives info about platelet activation, but not used anymore today

Question 4

Prolonged bleeding time with a normal platelet count suggests what type of disorder

Answer 4

Qualitative disorder: inherited (Glanzmann, Bernard-Soulier, storage pool disease, VWD)

Question 5

Which receptors are affected in Glanzmann, Bernard-Soulier disorders?

Answer 5

Gp1b in BS

GpIIbIIIa in Glanzman

Question 6

If VWD is suspected, what lab studies can be done to confirm the suspicion?

Answer 6

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

Question 7

How are factor VIII levels related to VWD?

Answer 7

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

Question 8

What lab tests differentiated hemophilia A from VWD?

Answer 8

Ristocetin activity: normal in HemA, low in VWD

vWF:Ag: normal in HemA, low/normal in VWD

Question 9

What causes a prolonged PT?

Answer 9

Liver disease
DIC
Warfarin therapy
Factor VII deficiency

Question 10

What causes a prolonged PTT?

Answer 10

Heparin theapy
Deficiency/inhibition of VIII, IX, XI, XII
Lupus anticoagulant

Question 11

What causes both a prolonged PT and PTT?

Answer 11

Heparin/Warfarin high doses
Dilution
Vit K deficiency
Liver disease
Paraproteins

Question 12

What is the utility of a mixing study?

Answer 12

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

Question 13

What are the most common inherited coagulation defects?

Answer 13

X-linked: Hemophilia A (VIII) and Hemophilia B (IX)

Question 14

How can you confirm normal platelet production?

Answer 14

Bone marrow aspirate showing megakaryocytic hyperplasia