Platelets and Primary Hemostasis

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Endstage DIC?

Hypocoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Liver failure

Hypocoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Viperidae envenomation

Hypocoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Vit K deficencies

Hypocoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Sepsis

Hypercoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Protein losing nephropathy

Hypercoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Endocrine disorders like DM or cushings

Hypercoagulation

Identify if the following is a cause of Hypocoagulation or hyper coagulation?

Severe anemias

Hypercoagulation

Under normal conditions the body will be ____ and ____?

Anti-coagulable - preventing clots

Profibrinolytic - break down clots fast

Laminar flow

What will we see in primary hemostasis?

Platelets

Petechation

What are characteristics of platelets in mammals?

Anucleate

Blue cytoplasms

Reddish cytoplasmic granules

What are characteristics of thrombocytes in non-mammals?

Round dense nucleus

Clear cytoplasm

Found in clumps

What is the in the phospholipid bilayer of a platelet>

Glycoproteins for activation adhesion and aggregation

How are platelets made?

Megakaryocytes break off

What is the life cycle of a platelet? What animals are they typically circulating for longer?

3-9 days

Splenictomized animals

Where is thrombopoietin produced? What will enhance its production?

Liver

IL-6 inflammatory

What is going to initiate coagulation?

Vascular inj stimulating Tissue factor expression on sub endothelial cells

What are the 4 steps of Primary hemostasis?

Platelet Adhesion

shape change

granual secretion

aggregation

What things might a platelet release in its granules?

ADP

Serotonin

Fibrinogen

Factor V (5)

Factor XI (11)

What are some things that could cause pseudothrombocytopeina?

Clumping - dramatic collection, improper handling/ EDTA

Macroplatelets

Given the following values from blood smear calculate the number of platelets for a dog?

5, 5, 4, 6, 5, 5, 4, 8, 5, 6

(5 + 5 + 4 + 6 + 5 + 5 + 4 + 8 + 5 + 6) / 10 =5.3

5.3 * 15,000 =79,500/uL

Given the following values from blood smear calculate the number of platelets for a cat?

5, 5, 4, 6, 5, 5, 4, 8, 5, 6

(5 + 5 + 4 + 6 + 5 + 5 + 4 + 8 + 5 + 6) / 10 =5.3

5.3 * 20,000 =106,000 /uL

What breed is predisposed to macrothrombocytopeina?

Cavalier king Charles - increased size of platelets

What will you see on CBC of macrothrombocytopenia?

Total platelet mass (plateletcrit) - normal

Giant platelets (High MPV)

Low platelet count

Name a few clinical signs of primary hemostasis?

Petechiae

Gingival bleeding

Hematuria

Melena

Epistaxis

What are 4 main causes of thrombocytopenia?

Splenic sequestration

Decreased production

Increased consumption/ utilization

Increased destruction

What are causes of splenic sequestration?

Splenic congestion - neoplasia/ heat stroke (uncommon)

What is the main cause of decreased production primary hemostasis?

Bone marrow panhypoplasia (decreased megakaryocytic)

-drugs (estrogen/ chemo)

-Toxins

-Radiation

What are infectious causes of decreased production primary hemostasis?

Erlichiosisi

FeLV

EIA

BVD

What are causes for platelet utilization/ consumption?

Trauma

Thromboembolic dz

Viperidae envenomation

Hemangiosarc

DIC

What is Primary immune mediated thrombocytopenia (ITP)?

Circulating platelets/ megakaryocytic destroyed by immune mediated mechanisms - Platelets numbers dramatically reduced

What Breeds do we typically see ITP?

Cocker spaniels

Toy poodles

If we see a normal platelet number on CBC but have evidence of bleeding/ clotting disorders what two things might we suspect?

Thrombocytopathy - impaired function

Deficiency in vWF

What is von willebrands factor used for?

Platelet adhesion to collagen

What breeds typically get VWD?

Doberman pinschers

What is Glanzmann thrombasthenia?

Defect in platelet aggregation due to genetic GPIIb/IIIa deficiency (Can't bind to fibrinogen)

Buccal mucosal bleeding time test is contraindicated in what pts?

Thrombocytopenic pts - no additional info collected

When would a buccal mucosal bleeding time (BMBT) test be indicated?

Normal platelet count w/ concurrent clinical signs of primary hemostatic disorders

When will we see a prolonged (over 4mins) BMBT test?

Thrombocytopenia

vWD

Thrombopathy

What are the two most common tests for vWD?

Elisa

Immunoelectrophoresis

What is the cause of physiologic Thrombocytosis?

Epinephrine induced splenic contraction -> increased number of circulating platelets

What is the cause of reactive or paraneoplastic thrombocytosis?

Inflammation or tumor production of IL-6 which stimulates TPO release -> increased platelet production

What is recovery from thrombocytopenia?

Rebound response causing increased bone marrow megakaryocyte production

What nutritional deficiency can occasionally cause thrombocytosis?

Iron deficiency