2.5Vm - Pathology Ii - Test Iii - Hemostatic Disorders

Front 1

What are clinical signs of platelet disorders usually associated with?

Back 1

Mucosal hemorrhage
- Petechia, epistaxis, internal bleeding, etc.

Front 2

Two types of platelet disorders

Back 2

- Quantitative (most common)
- Qualitative

Front 3

Thrombocytopenia (define)

Back 3

Decreased number of platelets

Front 4

Thrombocytosis (define)

Back 4

Increased numbers of platelets

Front 5

What is the most common platelet disorder?

Back 5

Thrombocytopenia

Front 6

Lifespan of a platelet

Back 6

7 - 10 days

Front 7

Two important causes of thrombocytopenia

Back 7

- Consumption
- Destruction

Front 8

What process consumes platelets?

Back 8

Clotting

Front 9

What causes destruction of platelets?

Back 9

Immune mediated disease

Front 10

3 immune-mediated diseases involved in the destruction of platelets

Back 10

- Idiopathic immune mediated thrombocytopenia (IMT)
- Evans Syndrome (IMT + IMHA)
- Immune mediated thrombocytopenia secondary to disease

Front 11

What's the most common cause of an increase in platelet numbers?

Back 11

Reactive thrombocytosis

Front 12

How does a reactive thrombocytosis occur?

Back 12

Secondary megakaryocytic hyperplasia in bone marrow due to generalized stimulation of one or more of the other cell lines in the marrow due to a physiologic demand for increased hematopoiesis

Front 13

What is a physiologic thrombocytosis associated with?

Back 13

Splenic contraction
- Transient increase

Front 14

In which thrombocytosis form are platelet levels extremely high?

Back 14

Neoplastic thrombocytosis

Front 15

Essential thrombocythemia (define)

Back 15

An uncontrolled and purposeless proliferation of megakaryocytes in the bone marrow
- Associated with physiologic thrombocytosis

Front 16

What is Essential thrombocythemia AKA?

Back 16

Chronic megakaryocytic leukemia

Front 17

What is often found in a bone marrow examination of a neoplastic thrombocytosis?

Back 17

Dwarf megakaryocytes

Front 18

What procedure can lead to a falsely low count of platelets?

Back 18

Bad venous collection due to clumping
- Seen mostly in cats

Front 19

What anticoagulant should be used when assessing platelets?

Which one should be used if that one fails?

Back 19

EDTA

Sodium Citrate

Front 20

What should be used to determine if a thrombocytopenia is from a consumptive process?

Back 20

Clotting profile

Front 21

What two things should be considered if a consumptive process is not found in a thrombocytopenia?

Back 21

- Decreased production
- Destruction

Front 22

Which form of qualitative disorders has a history of bleeding problems since youth?

Back 22

Hereditary primary platelet defects

Front 23

5 documented primary platelet disorders

Back 23

- Glanzmann's thrombasthenia
- Chedlak-Higashi syndrome
- Bovine thrombopathia
- Platelet dense granule effect
- Canine thrombopathia

Front 24

What is the most common inherited bleeding disorder in dogs?

Back 24

von Willebrand Disease

Front 25

What does vWD appear clinically as?

Back 25

Platelet defect

Front 26

Two sources of vWF in the body

Back 26

- Endothelial cells
- Circulating

Front 27

Type I vWD (multimers, structure)

Back 27

- Overall number of multimers decreased
- Structure of multimers is normal

Front 28

Type II vWD (multimers, structure)

Back 28

- Loss of high molecular weight multimers
- Structurally abnormal vWF molecule

Front 29

Type III vWD (multimers, structure)

Back 29

Loss of all multimers
- Nothing in notes about structure

Front 30

What breed is predisposed towards Type I vWD?

Back 30

Dobermans

Front 31

What breed is predisposed towards Type II vWD? (2)

Back 31

- German Shorthaired Pointers
- German Wirehaired Pointers

Front 32

What breed is predisposed towards Type III vWD? (2)

Back 32

- Scottish Terriers
- Shetland Sheepdogs

Front 33

6 causes of acquired platelet disorders

Back 33

- Medication administration (such as ASA)
- Disseiminated intravascular coagulation (DIC)
- Renal failure
- Liver disease
- Hyperactivity of platelets
- Paraproteinemias associated with plasma cell myeloma

Front 34

4 reasons to suspect a qualitative platelet disorder

Back 34

- Unexplained petechia
- Unexplained epistaxis
- Hemorrhage with normal platelet counts and normal coagulation
- Breed disposition

Front 35

What test assesses formation of platelet plug only?

Back 35

Buccal mucosal bleeding time test (BMT)
- Not affected by defects in clotting cascade

Front 36

Two things that a prolonged BMT is associated with

Back 36

- vWF Deficiency
- Qualitative platelet defects

Front 37

When is a von Willebrand Factor Antigen Assay performed?

Back 37

When platelet numbers are normal but has prolonged mucosal bleeding time

Front 38

What's used to measure total [vWF] in plasma?

Back 38

ELISA immunoassay

Front 39

What level of [vWF] in plasma is indicative of vWD?

Back 39

< 50% of normal

Front 40

Shortcoming of ELISA test for vWD testing

Back 40

Cannot differentiate between the three different types of vWD

Front 41

What occurs with too much fibrinolysis?

Back 41

Hemorrhage

Front 42

What occurs with too little fibrinolysis?

Back 42

Thrombosis

Front 43

What activates plasminogen to plasmin, and when?

Back 43

tPa (tissue plasminogen activator)
- When associated with fibrin

Front 44

What is the specific breakdown product of cross-linked fibrin?

Back 44

D-Dimer

Front 45

What is measuring of D-Dimer useful in?

Back 45

Determining if fibrinolysis of the clot is occurring

Front 46

Two tests for evaluating fibrinolysis

Back 46

- Measure FDPs in blood
- D-Dimer assays

Front 47

5 common causes of increased FDPs

Back 47

- DIC
- Thrombotic disease
- Liver disease
- Severe hemorrhage
- Inflammation (due to fibrin deposition)

Front 48

Can D-dimer assays determine if an animal has DIC?

Back 48

No

Front 49

Two causes of increased D-dimer

Back 49

- Thrombosis
- DIC

Front 50

3 things that Virchow's Triangle consists of

Back 50

- Damage to endothelium
- Alteration in blood flow
- Hypercoagulability

Front 51

What is Virchow's Triangle?

Back 51

Disease processes that alter the normal homeostatic balance of blood flow in vessels

Front 52

3 reasons hypercoagulability of blood occurs

Back 52

- Increased platelet activity
- Increased coagulation factor activity
- Decreased natural inhibitors (antithrombin and protein C)

Front 53

Two things that antithrombin inhibits

Back 53

- Thrombin
- Factor Xa

Front 54

What does low antithrombin put animals at risk for?

Back 54

Thromboembolic disease

Front 55

4 common disorders in the body associated with decreased antithrombin

Back 55

- Severe hepatic insufficiency
- Protein losing enteropathy
- Protein losing nephropathy
- Increased consumption (DIC)

Front 56

What is the most common reason for decreased antithrombin?

Back 56

Increased consumption (DIC)

Front 57

What level of normal antithrombin indicates a risk of thrombosis?

Back 57

< 60%

Front 58

What do normal levels of D-dimer suggest in terms of thrombolism?

Back 58

That no thrombosis is present

Front 59

Key feature of Disseminated Intravascular Coagulation (DIC)

Back 59

Widespread fibrin formation

Front 60

2 conditions in DIC that result in thrombosis

Back 60

- Tissue ischemia
- Consumption of platelets, coagulation factors, natural inhibitors, and fibrinolytic factors

Front 61

What does ischemia in DIC lead to?

Back 61

Multiple organ failure

Front 62

What does tissue anoxia lead to in DIC?

Back 62

Inhibition of antithrombin (through an acidosis)

Front 63

General mechanisms for DIC (6)

Back 63

- Stagnant blood flow
- Endothelial damage
- Release of large quantities of tissue factor
- Release of other coagulation factor activators
- Release of proteolytic enzymes
- Decreased clearance of activated coagulation factors and consumption of inhibitors of normal coagulation