Question

PATIENT 3 (Please answer all questions)

Melissa G., a 20-year-old woman who had been diagnosed with von Willebrand's disease, was scheduled for elective surgery. Her physician wanted to stabilize her von Willebrand's factor (vWF) before surgery and ordered a therapeutic trial of l-deamino-8-D-arginine vasopressin (DDAVP) (Stimate [desmopressin]), a non-blood treatment that increases the release of vWF from storage sites (endothelial lining of blood vessels). She was a weak responder, and her vWF levels did not increase adequately; therefore, the next option was to use blood component therapy. Melissa had approximately 20% of the normal concentration of vWF.

11. What would you expect Melissa's results to be on the following coagulation tests (increased, normal, or decreased)?

a. Prothrombin time (PT)
b. Activated partial thromboplastin time (APTT) c. Platelet count
d. Bleeding time
e. VIII:C
f. Ristocetin-induced platelet aggregation (RIPA)

12. Why did the physician try nonblood treatment before ordering blood component replacement therapy?

13. What is/are the component(s) of choice for stabilizing the concentration of vWF?

Answer 1

VWD is of three type type1(~85%) ,type 2(15%) and type 3(rare).

11.) A.) Prothrombin time: increased because in vwd patient the Prothrombin (factor 2 is decreased) resulting in increase in Prothrombin time.

B.) Activated partial thromboplastin time(APTT) : Increased because (it measures the cloting ability of factor 8,9,11 and 12) in Melissa the levels does not change after dDAVP.

C.) Platelet count: Normal because the VWD is inherited and it causes platelet dysfunction but does not affect value.

D.) Bleeding time: increased as the time taken to clot is increased the bleeding time will be more.

E.) VIII:C : decreased she had 20% of normal conc that is ~20 IU/dl which is very low seen in(type 2M /N and type 3).

F.) RIPA: Decreased or absent.

12.) dDAVP is acts via V2 receptor mediated platelet aggravation. Were it is used for checking the bleeding in vwd by releasing the factor 8 and vwf. Its partial effective in type2M and N, were completely ineffective in type 3. So to determine which type the physician must have given non blood component before administering blood components.

13.) Cryoprecipitate is one of choice for VWD, it contains 100units if antihemophilic factor and 250mg of fibrinogen were it is indicated in case of factor 8, vwf deficiency.(beacuse non responsive to dDAVP) 1unit of cryoprecipitate per 10kg bodyweight raises the fibrinogen of 50mg/dl in absence of bleeding.

Thankyou..