Bleeding tendencies Flashcards
What is the most common cause of an inherited haemophilia?
Von Willebrand disease.
What is the most common cause of inherited thrombophilia?
Activated protein C resistance.
How is Von Willebrand factor involved in clotting?
It is involved in platelet adhesion; it binds to collagen that is exposed in the vessel.
Is also a carrier for clotting factor VIII and helps to stabilise this clotting factor.
How does Von Willebrand disease often present?
With minor problems such as epistaxis, easy bruising, menorrhagia and bleeding after minor trauma or surgery (for example, after tooth extraction).
Which blood tests are you likely to be interested in for a patient with suspected Von Willebrand disease and what would the results be if a patient had Von Willebrand disease?
- Prolonged APTT
- Prolonged PT
- Increased bleeding time
- Reduded factor VIII
- Reduced VWF
Which blood tests are you likely to be interested in for a patient with suspected Von Willebrand disease and what would the results be if a patient had Von Willebrand disease?
- Prolonged APTT
- Prolonged PT
- Increased bleeding time
- Reduded factor VIII
- Reduced VWF
- *APTT is a reflection of the intrinsic pathway.
- **Factor VIII is involved in the intrinsic pathway.
1) Patients with haemophilia A and deficient in what?
2) Patients with haemophilia B are deficient in what?
3) What type of inheritance pattern do the haemophilias have?
1) Clotting factor 8.
2) Clotting factor 9.
3) X-linked recessive.
How can haemophilia present in neonates?
Intracranial haemorrhage, haematomas and prolonged bleeding after circumcision.
What is a feature of severe haemophilia and what can this lead to?
Haemarthrosis is a feature of severe haemophilia which can lead to joint deformity.
1) What might blood tests show in people with haemophilia?
2) How is a diagnosis of haemophilia made?
1) Prolonged APTT but normal PT.
2) By factor VIII or factor IX assays.
1) What might blood tests show in people with haemophilia?
2) How is a diagnosis of haemophilia made?
1) Prolonged APTT (as tests intrinsic and common pathways) BUT normal PT (because PT measures extrinsic and common pathways).
2) By factor VIII or factor IX assays.
Why can desmopressin be helpful in patients with mild factor VIII deficiency?
Because it stimulates VWF release from endothelial cells which promotes stabilisation of residual factor VIII.
In addition to medications, what other management is required for patients with haemophilia?
Avoid NSAIDs, Heparin and Warfarin as these can promote bleeding.
Avoid contact sports.
Name 2 acquired coagulation disorders.
1) Vitamin K deficiency
2) Liver disease
State 4 causes of vitamin K deficiency.
1) Haemorrhagic disease of the newborn.
2) Severe malnutrition
3) Malabsorption (cholestatic jaundice)
4) Warfarin.
State 3 causes of coagulation disorders which occur in the liver.
1) Reduced synthesis.
2) Thrombocytopenia due to hypersplenism (causes portal HTN).
3) DIC.
What are the 3 main categories of cause of thrombocytopenia?
1) Impaired production of platelets
2) Excessive destruction of platelets.
3) Sequestration of platelets in an enlarged spleen (splenomegaly/ hypersplenism).
Give 3 causes of impaired production go platelets.
Bone marrow failure Myelodysplastic syndromes Myeloma Aplastic anaemia HIV
Give 3 causes of excessive destruction of platelets.
- Immune/ idiopathic thrombocytopenia purpura.
- SLE/CLL/ viruses/ heparin
- Alloimmune neonatal thrombocytopenia
- DIC
- Thrombotic thrombocytopenia purpura
What is the difference between immune/ idiopathic and thrombotic thrombocytopenia purpura?
Immune/ idiopathic = bleeding due to destruction of platelets (body destroys platelets).
Thrombotic = Clotting due to platelets being used up
1) What can thrombotic thrombocytopenia purpura cause?
2) What causes immune/idiopathic thrombocytopenia purpura?
1) Fever, haemolytic anaemia and low platelet count. The cause is unknown.
2) Antibodies against GPIIb/IIIa receptor. Can occur in children who have had a recent viral illness.
What does disseminated intravascular coagulation arise due to?
Systemic activation of coagulation, often as part of an inflammatory response. It can be a sign of a serious, life-threatening underlying illness.
Give 3 conditions which can potentially lead to DIC.
Cancer Septicaemia Haemolytic infusion reactions Obstetric complications Trauma, burns and surgery Liver disease
**DIC only happens in seriously unwell patients.
Why can DIC cause both bleeding and thrombosis?
Can cause bleeding due to the condition using up all of the coagulation factors and clotting as there is less anticoagulant.
Generally, what happens in haemophilia?
Secondary haemostasis (formation of fibrin mesh) occurs at a much slower rate than normal, causing increased bleeding.
1) Deficiency in which factor is asymptomatic?
2) What happens in severe Von Willebrand disease?
1) Factor XII
2) CF VIII gets broken down faster than normal and so patients can become deficient in factor VIII (why VWD can mimic haemophilia A).
1) Which clotting factors does the liver synthesise?
2) Vitamin K is needed to synthesise and release which clotting factors?
1) All except from III. IV, VI and IX.
2) II, VII, IX, X.
State 5 clinical features associated with haemophilia.
Ecchymosis Haematomas Prolonged bleeding after a cut or surgery. Blood oozing after tooth extraction. GI Bleeding Haematuria Epistaxis Haemarthrosis Brain bleeds
1) What bleeding disorder might malabsorption cause?
2) How is this bleeding tendency treated?
1) Vitamin K deficiency.
2) IV Vitamin K (10mg) or in acute haemorrhage, with human prothrombin complex or FFP.
Aside from malabsorption, name 4 other causes of vitamin K deficiency.
Drugs (e.g. warfarin) Malnutrition Alcoholism Cystic fibrosis CKD Cholestatic disease
What blood test results might you see in a patient with vitamin K deficiency?
Increased PT
Increased or normal APTT.
