Unit 12: Platelets and Primary Hemostasis

The main function of the peripheral zone of a platelet is:

• platelet adhesion and aggregation

• maintain structure and support

• store platelet granules and secrete them during activation

• All of the above

platelet adhesion and aggregation

The main function of the sol-gel zone of a platelet is:

• platelet adhesion and aggregation

• maintain structure and support

• store platelet granules and secrete them during activation

• All of the above

maintain structure and support

The main function of the organelle zone of a platelet is:

• platelet adhesion and aggregation

• maintain structure and support

• store platelet granules and secrete them during activation

• All of the above

store platelet granules and secrete them during activation

Approximately 30% of peripheral platelets are stored in the:

• bone marrow

• spleen

• liver

• kidney

spleen

Adhesion is the term used to describe platelets ability to:

• provide a phospholipid surface for thrombin formation

• stick to each other

• stick to endothelial cells

• stick to exposed collagen

stick to exposed collagen

What factor is required for adhesion?

von Willebrand’s factor (vWF)

What factor in platelets allows for adhesion to vWF in exposed collagen?

• GPIb/IX

• GPIIb/IX

• GPIIb/IIIa

• GPIIIb/IIa

GPIb/IX

Aggregation is the term used to describe platelets ability to:

• provide a phospholipid surface for thrombin formation

• stick to each other

• stick to endothelial cells

• stick to exposed collagen

stick to each other

What factor in platelets allows for aggregation, binding fibrinogen?

• GPIb/IX

• GPIIb/IX

• GPIIb/IIIa

• GPIIIb/IIa

GPIIb/IIIa

A defect in primary hemostasis (platelet response to an injury) often results in:

• mucosal bleeding

• petechiae

• ecchymoses

• All of the above

All of the above

Common symptoms of platelet disorders include:

• petechiae

• ecchymoses

• hematomas

• All of the above

All of the above

Severe thrombocytopenia is likely to affect which of the following tests:

• PT

• APTT

• Bleeding time

• All of the above

Bleeding time

What are the 3 platelet adhesion disorders? Which ones are acquired or inherited?

1. Bernard-Soulier syndrome (BSS) - inherited

2. von Willebrand disease - inherited

3. myeloproliferative disorders (CML, ET, PV, MMM) - acquired

In Bernard-Soulier syndrome (BSS), platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

adhere

What qualitative bleeding disorder is a decreased or abnormal function in GPIb/IX factor?

• Glanzmann Thrombasthenia

• storage pool defects

• Bernard-Soulier syndrome

• May-Hegglin anomaly

Bernard-Soulier syndrome

In von Willebrand’s disease, platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

adhere

Which of the following is the most common hereditary bleeding disorder:        

• von Willebrand disease

• storage pool defects

• Bernard-Soulier syndrome

• May-Hegglin anomaly

von Willebrand disease

In myeloproliferative disorders (CML, ET, PV, MMM), platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

adhere

Abnormal aggregation with ristocetin is seen in what type of platelet disorders?

• adhesion

• aggregation

• secretion

• All of the above

adhesion

What are the 2 platelet aggregation disorders? Which ones are acquired or inherited?

1. Glanzmann Thrombasthenia (GT) - inherited

2. Uremia - acquired

In Glanzmann Thrombasthenia (GT), platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

aggregate

What qualitative bleeding disorder is a defect in GPIIb/IIIa factor?

• Glanzmann Thrombasthenia

• storage pool defects

• Bernard-Soulier syndrome

• May-Hegglin anomaly

Glanzmann Thrombasthenia

In uremia, platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

aggregate

Uremia causes a decrease in the synthesis of:

• ADP

• Collagen

• Ionized calcium

• Thromboxane A₂

Thromboxane A₂

What are the 4 platelet secretion disorders? Which ones are acquired or inherited?

1. Storage Pool diseases - inherited

2. Alpa granule deficiency (Gray Granule deficiency) - inherited

3. Defective Thromboxane A₂ Synthesis - inherited

4. Aspirin ingestion - acquired

In storage pool diseases, platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

secrete

Which of the following is the most common hereditary platelet function defects:        

• von Willebrand disease

• storage pool defects

• Bernard-Soulier syndrome

• May-Hegglin anomaly

storage pool defects

You perform whole blood lumiaggregometry on a patient who complains of easy bruising.  Aggregation and secretion are both diminished when the agonists thrombin, ADP, arachidonic acid, and collagen are used.  What is the most likely platelet abnormality:

• aspirin effect

• storage pool defects

• Bernard-Soulier syndrome

• May-Hegglin anomaly

storage pool defects

In Alpa Granule deficiency, platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

secrete

What platelet disorder is known as “Gray platelet syndrome?”

• Chediak-Higashi syndrome

• Pelger-Huet anomaly

• May-Hegglin anomaly

• Alp Granule deficiency

Alp Granule deficiency

In Defective Thromboxane A₂ Synthesis, platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

secrete

In Defective Thromboxane A₂ Synthesis, a decrease in A₂ synthesis is caused by a lack of this enzyme:

• dioxygenase

• cyclooxygenase

• lipooxygenase

• epoxygenase

cyclooxygenase

In aspirin ingestion, platelets lack the ability to:

• aggregate

• secrete

• adhere

• release fibrinogen

secrete

The most common acquired functional platelet disorder is due to:

• aspirin ingestion

• uremia

• vonWillebrand’s disease

• DIC

aspirin ingestion

Aspirin ingestion blocks the synthesis of:

• ADP

• Collagen

• Ionized calcium

• Thromboxane A₂

Thromboxane A2

The most common platelet disorder is:

• Bernard-Soulier syndrome

• Aspirin ingestion

• Thrombocytopenia

• Storage pool defects

Thrombocytopenia

May-Hegglin Anomaly causes thrombocytopenia by:

• decreasing platelet production

• increasing platelet destruction

• causing an abnormal platelet distribution

• All of the above

decreasing platelet production

Vitamin B₁₂ and Folate deficiencies cause thrombocytopenia by:

• decreasing platelet production

• increasing platelet destruction

• causing an abnormal platelet distribution

• All of the above

decreasing platelet production

Idiopathic Thrombocytopenia Purpura (ITP) causes thrombocytopenia by:

• decreasing platelet production

• increasing platelet destruction

• causing an abnormal platelet distribution

• All of the above

increasing platelet destruction

What is the most common form of thrombocytopenia?

• Neonatal alloimmune thrombocytopenia (NAIT)

• Heparin induced thrombocytopenia (HIT)

• Idiopathic thrombocytopenia purpura (ITP)

• None of the above

Idiopathic thrombocytopenia purpura (ITP)

Which of the following is NOT a hallmark of ITP:

• thrombocytopenia

• large overactive platelets

• severe anemia

• megakaryocte hypoplasia

sever anemia

(Acute/Chronic) ITP is seen in children ages 2-4 years or following viral infections, can last 3-6 weeks, and usually has a platelet count of < 20 × 10⁹/L.

acute ITP

(Acute/Chronic) ITP is seen in adults ages 20-40 years (usually adult females), can last 6-12 months, and usually has a platelet count of 30-80 × 10⁹/L.

chronic ITP

DIC, TTP, HUS, and artificial heart valves cause thrombocytopenia by:

• decreasing platelet production

• increasing platelet destruction

• causing an abnormal platelet distribution

• All of the above

increasing platelet destruction

Endotoxemia and Hypothermia cause thrombocytopenia by:

• decreasing platelet production

• increasing platelet destruction

• causing an abnormal platelet distribution

• All of the above

causing an abnormal platelet distribution

Sequestration of platelets in the lungs is known as ___________.

endotoxemia

Sequestration of platelets in the liver is known as ___________.

hypothermia

What type of disorders can cause persistent thrombocytosis?

myeloproliferative disorders