Haematology Flashcards
What is deep vein thrombosis?
Formation of a blood clot (thrombus) in a deep vein of the body
What are DVTs caused by?
Poor blood flow leading to clot formation
Give 5 risk factors for a DVT
- ) Venous flow stasis (e.g. immobility)
- ) Trauma/surgery
- ) Hypercoagulability
- ) Advanced age
- ) Sickle cell disease
- ) Pregnancy
- ) Taking oestrogen (HRT, pill)
- ) Cancer
- ) Obesity
- ) Thrombophilia
- ) Increased age
Give the steps of the clotting cascade (6)
1) Platelets adhere to endothelium
2) Aggregate forms
3) Clotting factors release
4) Prothrombin to thrombin
5) Thrombin catalyses fibrinogen to fibrin
6) Fibrin reinforces clot
Give 3 symptoms/signs of a DVT
- ) May be asymptomatic
- ) Calf warmth, tenderness, swelling, redness, pain
- ) Mild fever
- ) Pitting oedema
- ) Usually in just one leg
Give 3 tests for DVT
- ) D dimer
- ) US compression
- ) Thrombophilia test before anticoagulation if abnormal presentation
What is D dimer?
A fibrin degradation product
What does a normal/positive D dimer result mean?
Normal - excludes diagnosis
Positive - doesn’t confirm diagnosis
What do we do if an US compression if negative?
Perform again after a week as the clot may have spread up and become detectable
Give 3 parts of treatment of a DVT
- ) LMWH/ warfarin
- ) DOACs
- ) Underlying cause
- ) IVC filter in active bleeding/anticoagulants fail
What does DOACs stand for?
Direct oral anticoagulants
Give 2 methods of prevention of DVTs
- ) Stop oral contraceptive pill 4 weeks pre-op
- ) Mobilise early
- ) LMWH
- ) Compression stockings
What is a thrombosis?
Inappropriate blood coagulation occurs inside a vessel
What is arterial circulation high in?
Platelets
What is venous circulation high in?
Fibrin
Name 3 places an arterial thrombosis can occur and what it can cause
- ) Coronary circulation - MI
- ) Cerebral circulation - CVA/stroke
- ) Peripheral circulation - peripheral vascular disease
What is the treatment for a stroke?
Aspirin/clopidogrel, TPA
What is an embolism?
The passage of material through the venous or arterial circulations
What is the most common process of an embolism?
Thrombo-emolus from a DVT
Give 3 symptoms for an embolism
- ) Asymptomatic possible
- ) Transient dyspnoea
- ) Chest pain
- ) Haemoptysis
- ) Secondary effusion
- ) CV collapse
- ) Sudden death
What is a paradoxical embolism?
An embolus that travels through the venous circuit and then across the heart through a patent foramen ovale
Give 2 causes of a systemic arterial embolism
- ) Atherosclerotic plaques
- ) IE
What does the Virchow triad include?
- ) Stasis of blood flow
- ) Endothelial injury
- ) Hypercoagulability
What is a pulmonary embolism?
Large embolus that blocks the pulmonary arteries