Abnormal Hemostasis Flashcards
What is APTT?
Activated partial thromboplastin time (APTT) is a medical test that characterizes blood coagulation. It is an indicator of the Intrinsic Pathway.
What is PT/INR?
Prothrombin time (PT) and international normalized ratio (INR) are assays that evaluate the Extrinsic Pathway.
Thrombocytosis
Increased platelet count
Thrombocytopenia
Decreased platelet count
Primary fibrinolysis
In primary fibrinolysis, fibrinogen is converted into fibrinogen degradation products.
Secondary fibrinolysis
In secondary fibrinolysis both fibrin and fibrinogen are digested by plasmin.
What are the categories of quantitative platelet disorders?
Thrombocytopenia
Thrombocytosis
What are some of the common causes of thrombocytopenia?
- Bone marrow hypoplasia
- Hereditary thrombocytopenia
- Drug induced thrombocytopenia
Immune thrombocytopenic purpura (ITP)
Presentation with purpura on the skin and increased bleeding due to IgG mediated autoimmunity resulting in low platelets
Thrombotic thrombocytopenic purpura (TTP)
Cause formation of microscopic thrombi that can damage organs due to the inhibition of ADAMTS13 which results in multimers of vWF to increase in the blood and increase the amount of platelets in adhesion.
How does aspirin alter platelets?
It blocks the formation of thromboxane A2 as it is a COX inhibitor which leads to the inhibition of platelet aggregation
Glanzmann’s Thrombasthenia
Defect in GP IIb and IIIa that interferes with platelet aggregation and increases the bleeding time
Bernard-Soulier Disease
Defect in GP Ib prevents platelet adhesion which will increase the bleeding time
Storage Pool Disease
Decrease in the number of dense granules so aggregation is interfered with and bleeding is prolonged.
What are some causes of thrombocytosis?
- Splenectomy
- Reaction to cancer/drugs/infection
- Autonomous increase in platelets (thrombocythemia)
What are qualitative platelet disorders?
Platelet numbers are usually normal, however, platelet function is impaired.
What are some causes of qualitative platelet disorders?
- Disease induced platelet defects
- Drug induced platelet defects
- Diet induced platelet defects
What is the cause and manifestation of Gray Platelet Syndrome?
Lack of alpha granules. Present with purpura of unknown origin.
How does Omega-3 affect platelet function?
Blocks generation of thromboxane A2