Disorders of Hemostasis - Ex 6

Question 1

Vascular and platelet abnormalities - CS

Answer 1

Petechial hemorrhages

Question 2

Coagulation disorders - CS

Answer 2

Large hemorrhages:

• subcutaneous
• body cavities
• hemarthrosis (bleeding into joint spaces)

Question 3

Vascular disorders

Answer 3

Increased vessel fragility and/or defective sub endothelial collagen

Question 4

Acquired vascular disorders

Answer 4

Vasculitits (including envenomation)

Cushing’s Syndrome

Scurvy

Question 5

Lab Results - Vascular Disorders

Answer 5

Bleeding time: P 
ACT: N 
APTT: N
PT: N
QF: N
PLT: N to decreased (consumption)

Question 6

Thrombocytopenia:

<50,000/ul

<10,000/ul

Answer 6

<50,000ul –> increased bleeding secondary to trauma

<10,000ul –> spontaneous bleeding

Question 7

First rule out of thrombocytopenia

Answer 7

Artefact: platelet clump

esp in cats

Question 8

Thrombocytopenia - decreased production

Causes

Answer 8

1. Infectious agents (Ehrlichia)
2. Neoplasia (myelophthisis)
3. Drugs (estrogen)

Question 9

Thrombocytopenia - increased destruction

Causes

Answer 9

Primary Immune-mediated

Seen with IMHA

Question 10

Lab Results - Thrombocytopenia

Answer 10

Bleeding time: P 
ACT: N --> P 
APTT: N 
PT: N
QF: N

Question 11

Platelet Dysfunction - Acquired

Causes

Answer 11

NSAIDS (most common!!)

Others: 
Myeloma proteins 
FDPs 
Uremia 
Phenothiazines

Question 12

Lab Results - Platelet Dysfunction

Answer 12

BT: P 
ACT: N
APTT: N
PT: N
QF: N
vWF: N
PLT: N

Question 13

Platelet Dysfunction - Inherited

Answer 13

von Willebrand disease! (Type 1 is most common)

vWF on sub endothelium binds to platelets –> lack of vWF –> platelets cannot bind and form clot

Question 14

How do we measure vWF?

Answer 14

Measured immunologically (Ag)

Question 15

Types of vWD

Answer 15

Type 1:

• dec vWF:Ag
• dec all multimers
• *most common

Type 2:

• dec vWF:Ag
• dec all multimers, esp high MW
• *more severe than type 1

Type 3:

• vWF:Ag = undetectable
• *defect in the gene –> most severe form

Question 16

Lab Results - vWD

Answer 16

BT: P 
ACT: N --> P 
APTT: N --> P 
PT: N 
QF: N 
vWF: dec to absent

Question 17

Coagulation Disorders (Inherited) - Factors IX and VIII:C

Answer 17

IX - Dog, cat (severe bleeding)

VIII:C - dog, cat, sheep, horse (variable bleeding)

Question 18

Coagulation Disorders (Acquired) - Vit K and Hepatic Failure

Answer 18

1. Dec Vit K
   - vit K antagonists (rodenticides)
   - bile duct obstruction
   - malabsorption
   - dietary vit k deficiency
2. Hepatic failure
   - decreased production of factors

Question 19

Lab Results - Vit K antagonism/deficiency

Answer 19

BT: N
ACT: P 
APTT: P 
PT: P 
QF: N
vWF: N

Question 20

Lab Results - Hepatic Failure

Answer 20

BT: N
ACT: P 
APTT: P 
PT: P 
QF: Dec 
vWF: N

Question 21

Combined Disorders

Answer 21

DIC

• thrombocytopenia
• coagulopathy

Question 22

Lab Results - DIC

Answer 22

BT: P 
PLT: Dec
ACT: P 
APTT: P 
PT: P 
QF: P
FDPs: Inc
D-dimers: Inc 

***Everything is abnormal!