Bleeding disorders Flashcards
Causes of bleeding
Vascular disorders (rarely)
Platelet disorders
Defective coagulation
Thrombocytopenia
Low platelet count
When thrombocyte count <150 x10^9/ L
HOWEVER: symptoms usually occur when count <15
Causes:
Inherited
Acquired: drugs, ITP, DIC.
Symptoms: GL bleeds Menorrhagia Bruising Epistaxis (nose bleeds)
Causes of thrombocytopenia
Inherited:
Glanzmann’s
Acquired:
Drug related like aspirin and NSAIDs
ITP- immune thrombocytopenia
DIC- disseminated intravascular coagulation.
Symptoms of thrombocytopenia
GI bleeds
Menorrhagia
Epistaxis
Bruising
Normal platelet count
Thrombocytes range:
150-400 x 10^9 / L
Thrombocytopenia occurs when count is below range.
Symptoms occur when count is below 15.
ITP and its treatment (3)
Immune thrombocytopenia, a type of acquired thrombocytopenia.
Occurs when immune system destroys platelets.
Patients have purpura due to bleeding in the capillaries/ small vessels near the skin.
Treatment:
Steriods
IV immunoglobulins
Splenectomy occasionally.
DIC and lab results
Disseminated intravascular coagulation- a type of condition that causes acquired thrombocytopenia.
Blood clots and blacks small blood vessels.
Meningococcal DIC tests show:
High TT, PT and APTT.
Low fibrinogen and platelet levels
Increased D-dimers
Vascular bleeding
Occurs when there is a dysfunction in the blood vessel wall.
Can be inherited or acquired.
Inherited reasons for vascular bleeding.
Hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu).
Ehlers-Danlos syndrome.
Hereditary haemorrhagic telangiectasia.
Autosomal dominant genetic disorder that causes vascular bleeding.
Bleeding into the skin, mucous membranes and organs like the lungs, liver and brain.
Inherited haemophillia
Genetic condition that causes deficient blood coagulation due to missing coagulation factors.
Haemophillia A- X-linked related, lack of factor 8.
Haemophilia B- X-linked, lack of factor 9.
Clinical features of haemophillia
Joint and muscle bleed
Unexpected post-op bleeds
Joint disease- arthropathy
Haematoma- solid swelling of clotted blood in tissues.
Haemarthrosis- bleeding into the joints.
Family history
Tests of coagulation (6)
APTT- activated partial thromboplastin time
PT- partial thromboplastin time
TT- thrombin time
Fibrinogen level
Factor levels
Bleeding time
APTT and PT
APTT- activated partial thromboplastin time.
PT- partial thromboplastin time
APTT- assesses the intrinsic coagulation pathway. Involves the factors- VIII, IX, XI and XII
PT- assesses the extrinsic coagulation pathway. Involves the factors- VII, II, V and X.
Factors assessed in the APTT test
Factors: VIII, IX, XI and XII
8, 9, 11 and 12
Factors assessed in the PT test
Factors: II, V, VII and X
2, 5, 7 and 10.
Diagnosis if haemophillia
- APTT- this will be prolonged. This tests factors: VIII, IX, XI and XII
- PT- this will be normal. Tests for factors: II, V, VII and X.
- Test for factors VIII/ IX- this will be low.
<1 %= severe
1-5%= moderate
>5 %= mild.
Treatment of haemophilia
Infusion of recombinant factor VIII/ IX so that it is 50-100% of normal concentrations.
Prophylaxis treatment also used for the management of conditions.
Risks for haemophilia patients.
HIV, Hep C infections and vCJD
von Willebrand disease
A type of haemophillia where there is a deficiency of the von Willebrand factor due to autosomal dominant genetic cause.
Von Willebrand carries factor VIII in the blood and causes platelets to bind to collagen.
Diagnostic test will show:
Low vWF
Low FVIII in the plasma
Signs:
Mucocutaneous bleeds
Epistaxis
Menorrhagia
Test for von Willebrand disease
- APTT- longer. Due to lack of FVIII.
- Normal PT- extrinsic pathway unaffected.
- Blood test shows low vWF and FVIII.
- Prolong bleeding time.
- Defective platelet function
Treatment
Desmopressin- DDAVP
- This is the synthetic version of vasopressin (ADH)
Antifibrinolytics
IV plasma products
Acquired causes of haemophilia
Liver disease-
Defective clotting proteins
Impaired platelet function and fibrinolysis.
DIC-
Causes release of pro-coagulant into the blood..
This can causes bleeding.
Drugs that cause bleeding disorders
When taken in overdose- excess bleeding.
Iatrogenic- Heparin, Warfarin. Both used to treat cardiovascular problems
Overuse of DOACs
Argatroban
A DOAC that directly inhibits thrombin (FII)
Apixaban
A DOAC that directly inhibits Factor Xa (prothrombinase)
Vitamin K deficiency
Vit K used for gamma carboxylation of factors: II, VII, IX and X.
Causes:
Malabsorption
Biliary obstruction- jaundice in intestine.
Haemorrhagic disease in newborns
Pattern of bleeding for vascular and platelet causes
Bleeding into mucous membrane and skin.
Pattern of bleeding for coagulation disorders
Bleeding into joint and soft tissue.
