Bleeding disorders

Question 1

mixing studies are helpful for

Answer 1

differentiate betwen factor deficiency and an inhibitor as the cause a prolonged aPTT. It’s mixing the pt’s plasma with 1:1 ratio with normal plasma

Question 2

a prolonged aPTT can happen with

Answer 2

congenital or acquired von Willebrand dx and isolated deficiencies of 8, 9, and 11. Antiphospholipid antibodies (lupus inhibitor) causes prolonged aPTT but with thormbosis and not bleeding

Question 3

chronic liver disease causes

Answer 3

decreased synthesis of all vitamin K dependent clotting factors (II, VII, IX, and X) 10 9 7 2.. Will see prolonged PT and aPTT in chronic liver dx

Question 4

von Willebrand dx genetically inherited via

Answer 4

autosomal dominant disorder

Question 5

What can precipitate bleeding in von Willebrand dx pts?

Answer 5

NSAIDS

Question 6

deficiency in vWF can result in what lab change? What about only moderate vWF deficiency?

Answer 6

see prolonged aPTT (activated PTT) in deficiency of vWF In moderate vWF deficiency see no aPTT level change.

Question 7

When can there be a falsely normal aPTT level in vWF dx pts?

Answer 7

vWF is an acute phase reactant and so vWF and factor 8 levels can be elevated in times of stress, pregnancy, OCP, or liver disease. Tests should be repeated after this resolves

Question 8

If we suspect vWF dx what testing should we do?

Answer 8

If APTT and PT are ok but we strongly suspect they have vWF dx, please get: plasma vWF antigen, plasma vWF activity (ristocetin cofactor activity), Factor 8 activity

Question 9

ristocetin cofactor activity is

Answer 9

plasma vWF activity

Question 10

Treatment of vWF dx is

Answer 10

desmopressin or DDAVP which acts by releasing vWF and factor 8 from endothelial cells.

Question 11

what does von willebrand factor do?

Answer 11

it binds to platelets and subendothelial collagen receptors at exposed injury sites and binds to adja cent platelets and is a carrier protein to factor 8 which has reduced concentration and half life in an unbound stae. Thus a deficiency in vWF prolongs APTT

Question 12

minor factor 9 deficiency is

Answer 12

hemophilia B

Question 13

hemophilia B can present with

Answer 13

bleeding and normal coagulation studies (no prolonged PTT

Question 14

hemophilia A and B presents with

Answer 14

recurrent hemarthroses (joint bleeding) soft tissue hematoma in addition to mucocutaneous bleeding and

Question 15

inheritance pattern of hemophilia?

Answer 15

X linked inheritance pattern and so most patients are men

Question 16

hypofibrinogenemia

Answer 16

give cryoprecipitate

Question 17

Algorithm for evaluation of bleeding disorders

Answer 17

Question 18

Who is at risk for a vitamin K deficiency?

Answer 18

rare in healthy ind wiht balanced diet.

Seen in TPN, ppl on antibiotics, alcoholics, malnourished pts, and those with fat malabsorption syndromes (CF, primary biliary cirrhosis and celiac dx and inflammatory bowel dx)