Defects in Coagulation factors

Question 1

What are the general clinical features of secondary hemostasis ( coagulation cascade)?

Answer 1

Deep tissue bleeding into muscles and joints (hemarthrosis) and rebleeding after surgical procedures (eg circumcision and wisdom tooth extraction)

Question 2

PT

Answer 2

Prothrombin Time

• Factor 7
• Factor 2, 5,10 and fibrinogen

Extrinsic pathway

Question 3

PTT

Answer 3

Partial Thromboplastin Time
Intrinsic factors: 12, 11, 9, 8
Common: 2, 6, 10 and fibrinogen

Question 4

Hemophilia A

Defect:

Labs:

Tx:

Answer 4

X-linked disorder
Factor 8 deficiency

Labs:
increase PTT, normal PT
Decrease factor 8
Normal platelet count and bleeding

Tx: recombinant factor 8

Question 5

Hemophilia B

Defect

labs:

Answer 5

X linked disorder
Factor 9 deficiency

Labs:
increase PTT, normal PT
Decrease factor 9
Normal platelet count and bleeding

Question 6

Von Willebrand disease

Defect

Presentation:

Labs:

Tx:

Answer 6

most common inherited coagulation disorder

vWF deficiency
Autosomal dominant

Presents: mucosal and skin bleeding
Low vWF impairs platelet adhesion

Labs:
Increase bleeding time
Increase PTT (factor 8 is stabilized by vWF)
Normal PT
Abnormal ristocetin test (induces platelt agglutination by causing vWF to bind to platelet GPIb)

Tx: Desmopressin

Question 7

Coagulation factor inhibitor

Answer 7

Acquired antibody against factor 8 (most common) – can be against any factor though,

Clinically similar to hemophilia A (if factor 8 is target)

PTT does not correct upon mixing with normal plasma
- Hemophilia A will correct

Question 8

DIC

Answer 8

Wide spread activation of clotting due to pathological activation of coagulation cascade.

Causes: “STOP Making New Thrombi”

Sepsis
Trauma
Obstetric complication
acute Pancreatitis
Nephrotic syndrome
Transfusion

Lab: schiztocytes, increase fibrin split products (D-dimers), decrease fibrinogen, decrease V and 8