PATH - Coagulation Disorders

Question 1

Prothrombin Time (PT)

Answer 1

tests function of common and extrinsic pathway (factors I, II, V, VII, and X).

Defect–>INC PT

Question 2

International normalized ratio (INR)

Answer 2

calculated from PT
1 = normal, > 1 = prolonged

Most common test used to follow patients on *warfarin

Question 3

Partial Thromboplastin Time (PTT)

Answer 3

tests function of common and intrinsic pathway (all factors except VII and XIII).

Defect–>INC PTT

Question 4

Hemophilia A, B, or C

Answer 4

INC PTT

Intrinsic pathway coagulation defect.
ƒ-A: deficiency of factor VIII; X-linked recessive (most common)
-B: deficiency of factor *IX; X-linked recessive.
ƒ-C: deficiency of factor *XI; autosomal recessive

Macrohemorrhage in hemophilia—hemarthroses (bleeding into joints), easy bruising, bleeding after trauma or surgery

Treatment: desmopressin + factor VIII concentrate (A); factor IX concentrate
(B); factor XI concentrate (C).

Question 5

Vitamin K deficiency

Answer 5

INC PT
INC PTT

General coagulation defect
Bleeding time normal

DEC activity of factors II, VII, IX, X, protein C, protein S.