CPR 9.01 a+b Coagulation Intro, Disorders, Thrombophilia

Question 1

the arrest of bleeding by either the physiological properties of vasoconstriction and coagulation or through external intervention.

Answer 1

Hemostasis

Question 2

the sequential process by which the multiple coagulation factors of blood interact in the coagulation cascade, resulting in the formation of an insoluble fibrin clot.

Answer 2

Coagulation

Question 3

a series of serine proteases and their cofactors that interact to form thrombin that in turn converts fibrinogen to fibrin.

Answer 3

Procoagulants

Question 4

the action of the procoagulants is held in check by protease inhibitors that limit the clot formation/extension.

Answer 4

Anticoagulants

Question 5

Describe the process of primary hemostasis.

Answer 5

Formation of primary platelet plug

(a) Endothelial disruption causes collagen exposure. As platelets circulate in the bloodstream, they encounter this collagen.
(b) α2-βI or GPVI receptors located on the platelets can directly bind to collagen, or GPIb (IX/V) receptors on the platelets can bind to VWF that are are also bound directly to the exposed collagen.
(c) αII-β3 receptors are then activated on the platelet and either form dimers with other platelets or via VWF to create platelet plug. (primary hemostasis)

Question 6

What are the functions of platelets in the clotting mechanism?

Answer 6

(a) Primary hemostatic plug
(b) Secrete substances for Platelet recuruitment, Vessel contraction, Coagulation.
(c) Provides optimal surface for coagulation to proceed: phospholipid membrane. Optimized formation of complexes.

Question 7

Which factors make up the Extrinsic pathway?

Answer 7

Tissue factor and VII

Question 8

Which factors make up the Intrinsic pathway

Answer 8

XII, XI, IX+VIII

Question 9

Which factors make up the Common Pathway?

Answer 9

X+V, II, I

Question 10

The intrinsic tenase complex consists of what 4 components?

Answer 10

IXa, VIIIa, and Platelets (and Ca++)

Question 11

The extrinsic tenase complex consists of what 2 components?

Answer 11

TF and VIIa

Question 12

The Prothrombinase complex consists of what 4 components?

Answer 12

Xa, Va, and Platelets (and Ca++)

Question 13

Describe the prevalence of VWD

Answer 13

Most common bleeding disorder, about 1% of population. Equal in all ethnic groups.

Question 14

What are the 4-5 most common types of symptoms seen in VWD?

Answer 14

1. Mucosal-type bleeding: menorrhagia, epistaxis, bruising.
2. Excesive bleeding with trauma: Post-op, oral extraction, prolonged bleeding after cuts, postpartum hemorrhage.
3. GI bleeding seen with severe deficiency.
4. Increased risk of development of significant anemia as well as hysterectomy (if undiagnosed).

Question 15

Describe the general mechanism of ITP

Answer 15

2. Organ specific AI disorder. Platelet destruction→ Thrombocytopenia.

Question 16

What are the clinical findings of ITP?

Answer 16

easy bruising, petechiae and purpurae, epistaxis, hematuria, oral/GI bleeding.

Question 17

What are the mechanisms by which a baby might be Vitamin K deficient and how can this be prevented?

Answer 17

1. Newbown’s liver down’s use vitamin K efficiently or Low vitamin K stores (poor placentral transfer, sterile gut, breast milk bad content)
2. Prevention: Phrophylaxis via 0.5-1mg IM VK at birth.

Question 18

What are the coagulation factors affected in VKD?

Answer 18

II, VIII, IX, X, Protein C and S: 1972 C&S

Question 19

What are the coagulation factors deficient in Hemophilia? What is each type called?

Answer 19

VIII or IX (or XI)

(a) VIII: A IX: B XI: C

Question 20

What are the main categories for acquired thrombophilia

Answer 20

A. Increased Activation of Coagulation
B. Deficiencies and dysfunctions of coagulation regulation
1. Consumption of factors
2. Protein Loss
C. Decreased synthesis of anti-coagulation factors
1. Decreased antithrombin, protein C, protein S can lead to acute thrombosis.

Question 21

What are the clinical criteria for the diagnosis of APLS?

Answer 21

1. Clot: one or more episodes of venous, arterial, or small vessel thrombosis.
2. Pregnancy morbidity: one ore more miscarriages after 10th week. 3+ miscarriages before 10th wek. One or more normal pregnancies with pre-eclamspia or eclampsia with 34 or less gestational weeeks.

Question 22

What are the laboratory criteria for the diagnosis of APLS?

Answer 22

1. Positive on 2 or more occasions
   (a) High titer IgG and/or IgM aCL
   (b) IgG or IgM to beta-2GP1
   (c) Lupus anticoagulant