Platelet Disorders (haematology) Flashcards
What is primary haemostasis?
It is when platelets produce chemicals that make platelets nearby to be sticky and form a platelet plug.
What is secondary haemostasis?
It is when fibrin forms a mesh that traps platelets and RBCs forming a clot.
Two types of platelet disorders, and how they differ from each other.
Qualitative- with regards to the functioning of the platelets, the majority has normal platelet number.
Quantitative- with regards to the platelet number, majority functions normally.
Two types of quantitative platelet disorders
Thrombocytopenia and thrombocytosis
Name the four types of qualitative platelet disorders
Bernard-Soulier syndrome
Storage pool disorder
Von willebrand disease
Glanzmann’s thrombasthenia
What are the two types of thrombocytopenia? (4)
We have megakaryocytic thrombocytopenia whereby the bone marrow is fully functional but platelets are being destroyed in circulation.
-Here there will be high number of megakaryocyte bcs they are continuously stimulated to produce more platelets.
-Then amegakaryocytic theombopenia is when there are no megakaryocytes produced due to a bone marrow defect, platelet count will be low.
What are the three causes of thrombocytopenia?
Increased destruction- autoimmune diseases, ITP, DIC drugs.
Decreased production- Drugs, nutritional deficiencies, bone marrow infiltration.
Sequestration- any cause of splenomegaly such as portal hypertension and myelofibrosis.
Causes of thrombocytosis (3)
Reactive- Iron deficiency and infections.
Clonal- Myeloproliferative neoplasms
What are the three general tests taken for platelet disorders?
Full platelet count
Peripheral smear
Coagulation studies (PT and aPTT)
What are the examples of specific tests done in platelet disorders? (6)
-Autoimmune screen
-Bone marrow examination.
-Platelet aggregation studies
-Platelet function analysis
-Von willebrand antigen and function
-Electron microscopy
