Aani Haem: Clotting and bleeding Flashcards
Von Wilibrand Factor (VWF) is cleaved by which molecule?
ADAMTS13
VWF binds to which protein to bind platelets to collagen?
GP1B
What is another way of saying thrombin?
Factor 2A
What does thrombin do to speed up coagulation?
It speeds up activation of 8 to 8A and 5 to 5A
Which molecule is used to platelets bind directly to collagen?
GP1A
What breaks down the fibrin clot?
Plasmin
How is plasmin formed?
TPA (tissue plasmin activator) activates plasminogen into plasmin
What does warfarin do?
Inhibits Vit K dependent gamma carboxylation of factor 2,7,9,10 AND inhibits protein C and S and Z
What are the natural anticoagulants?
Protein C
Protein S
Anti Thrombin 3
TPA
What does TPA do?
TPA activates plasminogen to plasmin
What does heparin do?
It enhances the action of anti-thrombin 3 (which inhibits 2,11,9,10a)- same as warfarin but 11 instead of 7
Which factor does the extrinsic pathway begin with?
7
Virchow’s Triad?
Hypercoagubility
Vessel Damage
Blood stasis
Which coagulation factors can a pt have an excess of?
8,2, fibrinogen
Which acquired conditions can lead to hypercoagubility? (Therefore increased VTE risk)
Factor V leiden, Deficiency in protein C, deficiency in protein S, deficiency in antithrombin
Which acquired condition causes most severe risk of VTE?
Antithrombin deficiency
How does INR work?
The higher the number, the thinner the blood. The more risk factors a person has for developing VTE, the higher the target INR should be
When to stop LMWH?
When INR is within target range
How to reverse the effects of warfarin?
IV Vit K or Factor concentrates
How to reverse the effect of heparin?
Protamine Sulphate
Unwanted side effects of Heparin?
Heparin induced thrombocytopaenia (HIT)
Osteoporosis
These are more common in unfractionaed heparin
Which measurement is used to monitor heparin therapy?
APTT
Which measurement is used to monitor warfarin therapy?
PT
What is post-phlebitic syndrome?
Injury to veins/valves following a DVT
How to prevent post-phlebitic syndrome?
TED stockings
Explain genetics of Osler Weber Rendu (HHT)
Autosomal Dominant (positive FH common)
Sturge-Weber syndrome cosmetic defect?
Port-wine stain on face
Symptoms of Osler Weber Rendu? (HHT)
Bleeds e.g. nose bleeds & gut. Can lead to IDA.
Can get RED spider web telangiectasia on lips, skin etc.
Von Recklinghausen disease cutaneous presentation?
Cafe Au Lait spots and neurofibromas. (This condition is also called Neurofibromatosis 1- NF1)
Pzeuts-Jegher’s Syndrome?
Tan brown lesions on skin and oral mucosa - does not result in bleeding
Categories of platelet disorders
- Low Platelet FUNCTION (acquired or congenital)
- Low platelet COUNT (high destruction or low production)
Platelet COUNT disorders - give details
Low production: Bone marrow failure
Increased destruction: AITP (autoimmune thrombocytopaenic purpura)/ Drugs (e.g. Herparin) /DIC / HUS/ TTP - these vessel abnormalities cause damage to platelets as they pass through fibrin mesh
Platelet FUNCTION disorders - give details
Acquired: Aspirin . uraemia , Cardiopulmonary bypass - cardiac surgery releases PF4 which induces Heparin Induced Thrombocytopaenia
Congenital: Thrombasthenia (Glycoprotein deficiency) & storage pool disease
How does Aspirin affect platelets?
It inhibits COX 1 and COX 2. These are needed to create thromboxane A2 for platelet aggregation
Is Aspirin reversible or irreversible?
Irreversible
What is Storage Pool disease?
Platelets don’t have enough granules so leads to platelet dysfunction –> bleeding
What are the types of immune thrombocytopaenic purpura?
Acute and Chronic.
What are the differences between Acute and Chronic AITP? (Thombocytopaenic Purpura)
Acute: Children Equal genders Preceding infection is common Self limiting VERY low plt count (<20,000) Resolves after 1-6 weeks
Chronic: Adults Females more likely Rare to have preceding infection IVIg/Steroids/splenectomy usually needed Moderately low plt count (<50,000) Long Term
Which factor is deficient in Haemophilia A?
8 (Sounds like A) A Eight
Which factor is deficient in Haemophilia B?
9
Which haemophilia is more common?
A
How can VWF help Haemophilia A?
VWF carries factor 8 in circulation
Treatment of Haemophilia?
Factor concentrates
How do you diagnose Haemophilia?
Normal PT, High APTT
How do antibiotics affect bleeding?
Abx can prevent warfarin breakdown so increase warfarin levels so reduce coagulation factors levels and lead to bleeding
Causes of DIC?
- Trauma
- Malignancy
- Sepsis
- Toxins
Diagnosing DIC?
- Low platelets
- Low fibrinogen
- High D dimers
- High FDP
- Long PT
How to treat DIC?
FFP
Transfusions
Platelets
Diagnosing von wilibrand disease
- Low VWF
- Low Factor 8
- High APTT
- High bleeding time