This patient with very low factor V (FV) activity is bleeding into his leg. Which of the following therapies is/are appropriate?

Fresh frozen plasma
FV concentrate
Trick question! There is no FV concentrate available.
Tranexamic acid
Antifibrinolytic agents are supplemental treatment provided there is no bleeding in the unitary tract.
Platelet transfusion
Platelets contain FV, so this is a reasonable strategy to supplement fresh frozen plasma if the latter is not sufficient to raise FV levels > 20%.
Cryoprecipitate is enriched in fibrinogen, FVIII, VWF and FXIII, not FV.

Although the mixing study did not show evidence of an inhibitor towards factor V (FV), there is concern that there is a clearance-enhancing antibody against FV. What is a reasonable treatment strategy to eradicate the inhibitor (more than one answer may be correct)?

There are no studies looking at the relative efficacy of different immunusuppressants in patients with acquired clotting factor inhibitors, but prednisone plus cyclophosphamide or rituximab are more commonly used than cyclosporine.
Anti-thymocyte globulin (ATG)
High dose prednisone
Prednisone and rituximab

This patient was treated as follows:

  • Packed red blood cells 17 units over 17 days
  • Fresh frozen plasma 18 units over 17 days
  • Platelets 19 units over 17 days
  • Prednisone 1 mg/kg/day for 21 days, then tapering doses

The following is his time course:

PT (sec)PTT (sec)FV level (%)Transfusion
Day -512.327.7NDNo transfusion
Day 133.5121.6NDNo transfusion
Day 236.11502Rx2, FFPx3
Day 3421503R, FFP
Day 443.51502Rx2, FFP, Px3
Day 5 46.91503No transfusion
Day 641.6146.52Rx2, FFP, Px2
Day 742150NDR, FFP, P
Day 8 26.9104.3NDR
Day 930.5120.34R, P
Day 10 27.9119.96R, FFP, P
Day 1122.7101.78R, FFPx2, Px2
Day 1222.197.910R, FFP, Px2
Day 13 20.287.3NDR, FFPx3
Day 1417.348.6NDPx2
Day 15 15.337.234R, FFPx2, Px2
Day 1615.635.841FFP
Day 1713.226.483No transfusion
ND, not done; R, red cell transfusion; FFP, fresh frozen plasma; P, platelet transfusion

As can be seen from the data in the previous slide, the patient’s FV activity level increased, and his PT and aPTT decreased over the ensuing 17 days while being treated with high dose prednisone (to reduce inhibitor level), fresh frozen plasma and platelets (to increase the FV level), and packed red cells to replace blood loss from the muscle hematoma (he also developed some GI blood loss, which contributed to the anemia).

The following is the time course for serum haptoglobin and an unknown serum marker:

PT (sec)? (IU/L)
Day 31431170
Day 4ND1453
Day 5 157ND
Day 6ND961
Day 8 105ND
Day 9-16NDND
Day 1737ND
Day 26 – 31<10400-500
Day 3223318
Day 3343270
ND, not done; R, red cell transfusion; FFP, fresh frozen plasma; P, platelet transfusion

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