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Questions and Answers
What is the subnormal platelet count in circulating blood?
What is the subnormal platelet count in circulating blood?
- 100 X 10^9/L
- Above 100 X 10^9/L
- Below 100 X 10^9/L (correct)
- Below 50 X 10^9/L
Inherited thrombocytopenias are very common disorders.
Inherited thrombocytopenias are very common disorders.
False (B)
Name one condition that may present with thrombocytopenia due to generalized bone marrow failure.
Name one condition that may present with thrombocytopenia due to generalized bone marrow failure.
Fanconi anemia
The commonest form of inherited thrombocytopenia involves _____ platelet size and increased platelet volume.
The commonest form of inherited thrombocytopenia involves _____ platelet size and increased platelet volume.
Which of the following is NOT a characteristic of inherited platelet disorders?
Which of the following is NOT a characteristic of inherited platelet disorders?
Platelets play a role in providing a surface for promoting blood coagulation.
Platelets play a role in providing a surface for promoting blood coagulation.
What is the term for a subnormal number of platelets in circulating blood?
What is the term for a subnormal number of platelets in circulating blood?
Match the inherited platelet disorder to its characteristic:
Match the inherited platelet disorder to its characteristic:
Which of the following is a cause of thrombocytopenia?
Which of the following is a cause of thrombocytopenia?
Bernard-Soulier syndrome is characterized by a low platelet count.
Bernard-Soulier syndrome is characterized by a low platelet count.
What is the primary defect in Bernard-Soulier syndrome?
What is the primary defect in Bernard-Soulier syndrome?
The normal diameter of platelets is typically less than ______ micrometers.
The normal diameter of platelets is typically less than ______ micrometers.
Match the following conditions with their characteristics:
Match the following conditions with their characteristics:
What is the primary function of phospholipase C in platelet signaling?
What is the primary function of phospholipase C in platelet signaling?
What is the role of Thrombopoietin (TPO)?
What is the role of Thrombopoietin (TPO)?
Defects in phospholipase C do not affect platelet function despite the presence of thromboxane A2.
Defects in phospholipase C do not affect platelet function despite the presence of thromboxane A2.
Thrombocytopathies are marked by a decrease in platelet size.
Thrombocytopathies are marked by a decrease in platelet size.
What is the normal function compromised in thrombocytopathies?
What is the normal function compromised in thrombocytopathies?
What are the primary aggregating agents that induce platelet aggregation?
What are the primary aggregating agents that induce platelet aggregation?
Glanzmann’s thrombosthenia is characterized by prolonged bleeding time, normal platelet count, and absence of platelet aggregation in response to _____ agents.
Glanzmann’s thrombosthenia is characterized by prolonged bleeding time, normal platelet count, and absence of platelet aggregation in response to _____ agents.
Which of the following therapies is NOT typically used for congenital thrombocytopenia?
Which of the following therapies is NOT typically used for congenital thrombocytopenia?
Match the substance with its corresponding action or characteristic.
Match the substance with its corresponding action or characteristic.
Splenectomy is ineffective for patients with inherited thrombocytopathies.
Splenectomy is ineffective for patients with inherited thrombocytopathies.
What is the role of recombinant FVIIa in therapy?
What is the role of recombinant FVIIa in therapy?
Flashcards
Thrombocytopenia
Thrombocytopenia
A condition where the number of platelets in the blood is below normal, usually below 100 x 10^9/L.
Platelet Adhesion
Platelet Adhesion
Platelets do not attach to normal, healthy blood vessels.
Platelet Plug Formation
Platelet Plug Formation
Platelets form a plug at the site of a damaged blood vessel to stop bleeding.
Wiskott-Aldrich Syndrome
Wiskott-Aldrich Syndrome
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Inherited Platelet Disorders
Inherited Platelet Disorders
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May-Hegglin Anomaly
May-Hegglin Anomaly
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Bernard-Soulier Syndrome
Bernard-Soulier Syndrome
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Inherited Thrombocytopenia with Reduced Platelet Size (Example: Wiskott-Aldrich Syndrome)
Inherited Thrombocytopenia with Reduced Platelet Size (Example: Wiskott-Aldrich Syndrome)
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Thrombocytopenia due to Abnormal Regulation
Thrombocytopenia due to Abnormal Regulation
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Thrombocytopenia due to Increased Destruction
Thrombocytopenia due to Increased Destruction
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Thrombocytopenia due to Splenic Sequestration
Thrombocytopenia due to Splenic Sequestration
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Thrombocytopenia due to Ineffective Thrombopoiesis
Thrombocytopenia due to Ineffective Thrombopoiesis
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Thrombocytopathies
Thrombocytopathies
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Bernard-Soulier Syndrome (BSS)
Bernard-Soulier Syndrome (BSS)
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Defective Binding to VWF
Defective Binding to VWF
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Thrombin
Thrombin
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Adrenaline (Epinephrine)
Adrenaline (Epinephrine)
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ADP (Adenosine Diphosphate)
ADP (Adenosine Diphosphate)
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Secondary Aggregating Agents
Secondary Aggregating Agents
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Glanzmann's Thrombasthenia
Glanzmann's Thrombasthenia
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Study Notes
Course Information
- Course title: Clinical Laboratory Sciences
- Course number: MCLS7211
- Course name: Blood Homeostasis and Coagulation
- Semester: First Semester
- Academic year: 2024/2025
- Lecturer: Dr. Ola Karmi
- Email: [email protected]
Platelets Disorders
- Platelets do not adhere normally to intact healthy endothelium
- Platelets help arrest bleeding from damaged blood vessels
- Platelets plug the rupture in vessel walls
- Platelets provide a surface for promoting blood coagulation
Coagulation Cascade and Fibrinolysis
- Coagulation and fibrinolysis work together to maintain a delicate balance
- Coagulation is a cascade of reactions that form a clot
- Fibrinolysis breaks down the clot when healing is complete
Thrombocytopenia
- A subnormal number of platelets in circulating blood (usually below 100 X10^9/L)
- Clinical symptoms usually show up when platelet count is less than 50, and severe and spontaneous bleeding occur with a platelet count of less than 10
- Low platelet count is the most common cause of severe bleeding
- Risk of hemorrhage is inversely proportional to the platelet count
Causes of Thrombocytopenia (Non-Inherited)
- Drugs and Chemicals: Maternal use is common, causing suppression of platelet production or direct damage to platelets. Certain chemicals cross the placenta, leading to severe thrombocytopenia in newborns.
- Infections: Infections, such as viral infections, toxoplasmosis, CMV, rubella, herpesviruses, or hepatitis, cause mild to severe thrombocytopenia in newborns.
- Infiltration of Bone Marrow: Rare cases with disseminated reticuloendotheliosis and congenital leukemia cause thrombocytopenia. This often involves the myeloid and erythroid depressions in children.
- Isoimmune thrombocytopenia: Antibodies formed in the mother due to active immunization of the mother by fetal platelets (IgG). Elevated in newborns of PIA1-negative mothers and PIA1-positive fetuses, often causing severe bleeding.
Causes of Thrombocytopenia (Inherited)
- Inherited thrombocytopenia with reduced platelet size: Example: Wiskott-Aldrich syndrome (rare, X-linked recessive disorder)
- Inherited thrombocytopenia with normal platelet size: Congenital deficiency of megakaryocytes. Increased volume and reduced number of platelets, especially common.
- Inherited thrombocytopenia with increased platelet size: Giant platelets are associated with inherited diseases.
Classification of Congenital Platelet Disorders
- Thrombocytopenia: Non-inherited and inherited disorders.
- Thrombocytopathies: Disorders associated with reduced platelet size, normal size, or increased size; disorders of platelet adhesion, signalling, and aggregation.
Platelet Structures
- Key structures are discussed in images illustrating platelet disorders.
Laboratory Evaluation
- Screening tests for thromboyctpenia: Decreased platelet count
- Screening tests for thrombocytopathies: Usually normal platelet count
Therapy
- Severe congenital thrombocytopenia: Washed maternal platelets, corticosteroids, or exchange transfusions.
- Splenectomy is effective in inherited thrombocytopenia.
- Patient education, avoiding trauma, and regular dental care.
- Suppress bleeding (antifibrinolytic agents), desmopressin, recombinant FVIIa.
- Platelet transfusions from HLA-matched donors.
- Allogenic bone marrow transplantation is a possible cure.
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Description
Test your knowledge on platelet disorders, the coagulation cascade, and fibrinolysis as part of the Blood Homeostasis and Coagulation course. This quiz will cover important definitions, mechanisms, and clinical implications related to platelets and coagulation processes.
