4.1 Primary Hemostasis and Related Bleeding Disorders Flashcards

1
Q

What is the function of primary hemostasis?

A

Formation of a weak platelet plug

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2
Q

What is the function of secondary hemostasis?

A

Stabilization of the platelet plug formed in primary hemostasis

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3
Q

What are the 2 sources of von Willebrand’s Factor?

A
  • Platelets

- Endothelial cells in the Weibel-Palade body

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4
Q

What is the protein that binds the platelets to vWF?

A

GP Ib

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5
Q

What is the first response to blood vessel damage?

A

Vasoconstriction

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6
Q

After vasoconstriction in response to injury, what occurs next?

A

vWF will bind to collagen on the disrupted tissue and then platelet adhesion to vWF will occur via GP Ib binding

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7
Q

What happens to the platelets after adhesion?

A

Adhesion will lead to platelet activation with a change in the conformation of the platelets and lead to the release of ADP which will expose GP IIb/IIIa and TXA2, which will promote platelet aggregation

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8
Q

What occurs during platelet aggregation?

A

Platelets link to each other with GP IIb/IIIa via fibrinogen and form a weak platelet plug, marking the end of primary hemostasis.

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9
Q

What are the 2 major types of primary hemostasis disorders?

A

Quantitative and Qualitative

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10
Q

What is the major symptom of primary hemostasis disease?

A

Skin and mucosal bleeding - epistaxis is a major one

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11
Q

What is immune thrombocytopenic purpura (ITP)?

A

Autoimmune disease where IgG is made in the spleen against GP IIb/IIIa

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12
Q

Who gets ITP most often?

A

The acute form is most often found in children.

The chronic form is most often found in adult women.

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13
Q

What are the lab findings in ITP?

A
  • Decreased platelet count
  • Normal PT/PTT
  • Increased megakaryocytes in bone marrow
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14
Q

What is microangiopathic hemolytic anemia?

A

Pathologic formation of platelet micro thrombi in small vessels which consumes the platelets and leads the the shearing of the RBCs

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15
Q

With what other syndromes is microangiopathic hemolytic anemia seen with?

A

Thrombotic Thrombocytopenic Purpura

Hemolytic Uremic Syndrome

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16
Q

What is the cause of TTP?

A

Due to decreased ADAMTS13 which normally cleaves vWF multimers into monomers. The multimers will lead to abnormal platelet adhesion and result in the micro thrombi

17
Q

What are the general findings of TTP and HUS?

A

Skin and mucosal bleeding
Microangiopathic hemolytic anemia
Renal failure (HUS)
CNS abnormalities (TTP)

18
Q

What is Bernard-Soulier Syndrome caused by?

A

GP Ib defect that impair platelet adhesion to vWF

19
Q

What is Glanzmann Thrombasthenia cause by?

A

GP IIb/IIIa defect that impairs platelet aggregation

20
Q

What is the effect of uremia on platelets?

A

Uremia disrupts platelet function so both adhesion and aggregation are impaired