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36 Cards in this Set
- Front
- Back
Three types of Clinical disorders of haemostasis? |
Vascular disorders Platelet disorders Coagulation disorders |
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What is purpura? |
Subcutaneous bleeding Caused by atropy of supporting tissues of cetaneous blood vessels |
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What is Petechiae? What is the cause? |
Red, flat pinhead spots Due to localised microvasculature haemorrhage |
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What is Ecchymoses? |
Bruises Localised haemorrhage, often involving multiple microvessels |
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What is Epistaxis? |
Nose bleed
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What is Haemarthrosis?
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Bleeding into joints |
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What is Telangectasia?
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Increase in size of microvessels, usually in skin |
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What is Haematoma? |
Localised collection of blood Ccan occur in any tissue, e.g. deep within a muscle |
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Cause of vascular disorders? |
May be inherited or acquired
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Name an inherited vascular disorder? |
Hereditary haemorrhagic telangiectasia - Autosomal dominant inheritance - malformed and thin walled capillaries - –Spontaneous bleeding into skin and mucosa –Defects can lead to haemorrhage andanaemia – (due to repeated haemorrhages) |
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What is the cause of acquired vascular disorders? What are the symptoms? |
Allergic reactions , infection or nutrition Results in purpuras with mucous membrane bleeding Tendency to bruise following minimaltrauma |
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Give an example of an acquired vascular disorder |
Allergic purpura - autoimmune inflammation - effusion of blood into skin - insect bites, food Infection induced purpura - scarlet fever leads to autoimmune damage |
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Give an example of a acquired, nutritional vascular disorder |
Scurvy - Inadequate collagen synthesis - Cell-cell adhesion breaks down in endothelium- Also causes platelet defects |
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Give an example of a disorder due to platelet numbers? What is the cause |
Thrombocytopaenia Can be caused by immune or non-immune reasons |
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cause of ITP |
Formation of autoimmune Ab against platelets- destroys platelets (only last hours),- inhibits megakarypoiesis - impair platelet function Chronic - associated with SLE, HIV |
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What is Immune thrombocytopaenic purpura, ITP? Effects |
F:M = 3:1, 20-30 years in chronic Hl of platelets - 2 days Half life of platelets - minutes from 2-3 days |
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What is the treatment for ITP? |
Do nothing - 90% recover. chronic - no recovery Chronic - aim to maintain platelet count to stop spontaneous bruising Splenectomy - stop sequestration of platelets . 50-90% remission •Thrombopoietin agonists have been used toincrease platelet production |
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Example of Druginduced thrombocytopaenia
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Penicillin, paracetamol - •Induction of anti-platelet antibodies |
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Non-immunethrombocytopaenia |
TTP •Microthrombiformed in arterioles and capillaries –Plateletsactivated and deposited at multiple sites leads to massive consumption |
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Give an example of a hereditary and acquired disorder of platelet function |
Hereditary - Glanzmann’s thrombasthenia - defect in platelet aggregation due to GPIIb:GPIIIa. petechial rash. •Autosomal recessive Acquired - aspirin - inhibits granule release, irreversible for 7 days. Binds COX (low Kd) + ibuprofen |
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Types of coagulation disorders |
•X-linked coagulation disorders–HaemophiliaA–HaemophiliaB •Autosomal recessive coagulation disorders–Afibrinogenaemia(most common) – can’t form crosslinked fibrin. treat - purifiedfibrinogen •Autosomal dominant coagulation disordersvon Willebrandsdisease – vWfactor defect. Affects primary and secondary haemastasis |
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Give an example of a Hereditary coagulation disorder and mutation 10% of patient have what? |
Often single gene defect X-linked coagulation disorders- Haemophilia A Half of the patients have missense or frameshift mutations or deletions in factor VIII gene –10%Haemophilia A patients have antibodies to factor VIII |
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When is HaemophiliaA possible in females? |
–spontaneousmutant father, carrier mother
–haemophiliacfather, carrier mother |
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What is the pathology of Haemophilia A? |
Traumatic bleeding Haemarthrosis - Bleeding into joints from synovial vessels Haematomas - Subcutaneous and muscular bleeding |
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What is the treatment for Haemophilia A? |
Factor VIII replacement Fresh plasma - best if fresh, but can transmit disease So use Cryoprecipitate - Freezeand slow thaw Best method - Recombinant Factor VIII. Expensive |
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Cause of Haemophilia B? |
Deficiency or mutation in factor IX- modulates extrinsic coagulation Similar symptoms |
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What is the cause and symptoms of vW disease? |
Defect/deficiency in vW factor Dominant autosomal disorder |
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What is the effect of vW disease? |
Primary - Poor platelet adhesion to wounds Secondary - reduced factor VIII levels |
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Treatment for vW disease? |
Small daily doses of plasma will increase factor VIII |
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What is the result of Acquired coagulation disorders? |
Multiple failure in coagulation cascade
Involves thrombocytopaenia and/or vascular defects Spontaneous skin purpura |
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What are 4 major causes of Acquired coagulation disorders? |
Vitamin K deficiency Liver disease Inhibitors of coagulation Drug induced |
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What is vitamin K needed for? |
Synthesis of active prothrombin, factors VII, IX and X and proteins C and S are dependent on vitamin K Required for g-carboxylation of glutamic acid |
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What is the cause of liver disease? |
Deficient synthesis and secretion of coagulation factors by liver Correlates with decrease in albumin production •Deficient clearance of activatedcoagulation factors - diffuseintravascular coagulation |
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Druginduced bleeding disorders |
Antibiotics - –interfere with fibrin polymerisation–May affect platelet function |
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What is a platelet-related side effect of aspirin treatment? |
Inhibits cyclo-oxygenase - impaired thromboxane A2 synthesis Impairs release reaction and aggregation of arachidonic acid, collagen, adrenaline and ADP |
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What is a source of vitamin K? |
Green vegetables and bacterial synthesis in the gut |