Hematology

Question 1

Von Willebrand Disease

Answer 1

MC congenital bleeding disorder

vWF made in endothelium. allows platelets to bind to exposed collagen in walls of injured vessels, initiate platelet plug formation. Carries Factor 8, protects it from degradation

3 types:
Type 1 (AD): mild deficiency of vWF; Tx: Desmopressin
Type 2 (AD): qualitative deficiency of vWF; Tx: Desmopressin
Type 3 (AR): almost absence vWF; Tx: F8/vWF concentrate

Question 2

Factor V Leiden

Answer 2

MC inheritable hyper coagulable disorder
Results in venous thrombosis

Altered factor V can’t be inactivated by Protein C, increases thrombin formation

Question 3

Antithrombin III deficiency

Answer 3

Antithrombin III (protease) inhibits coagulation by neutralizing activity of thrombin (F IIa, IXa, Xa)

Deficiency of this will leak to increased activity of these factors

MCC of resistance to unfractionated heparin (unable to obtain therapeutic levels of aPTT while on heparin drip_

Question 4

Protein C or S deficiency

Answer 4

Congenital or acquired
Protein C + S inactivate F Va and VIIIa -> decreases thrombin formation

When protein C or S are deficient, thrombin is increased

Question 5

Prothrombin gene mutation

Answer 5

Affects prothrombin mRNA –> decreased prothrombin levels –> increased thrombin levels

Question 6

Aspirin

Answer 6

Irreversibly inhibits PG synthesis in platelets
by acetylating cyclo-oxygenase
Permanent platelet dysfunction
Abnormal bleeding time

Question 7

HIT

Answer 7

Body forms IgG Ab to platelet factor 4

Tx: stop heparin, send serotonin release assay (confirmatory test)