thrombotic disoders Flashcards
What is venous thromboembolism (VTE)?
Venous thromboembolism (VTE) is the process of blood clot formation in the veins. It includes deep vein thrombosis (DVT) and pulmonary embolism (PE).
What is provoked VTE?
Provoked VTE refers to a VTE event that has a clear precipitating cause identified from the patient’s history or diagnostic tests
What is unprovoked VTE?
Unprovoked VTE refers to a VTE event that does not have a clear cause identified from the patient’s history or diagnostic tests.
What is thrombophilia?
Thrombophilia is a condition in which the blood in the body clots more easily than normal. This can increase the risk of developing blood clots, including VTE.
What are the three components of Virchow’s triad?
The three components of Virchow’s triad are circulatory stasis, hypercoagulable state, and vascular injury.
What are some causes of circulatory stasis?
Causes of circulatory stasis include bed rest, lower limb orthopaedic surgery, major abdominal surgery, pregnancy, and long haul flights or long car journeys.
What are some causes of hypercoagulable states?
Causes of hypercoagulable states include smoking, oestrogens (oral contraceptives, HRT), active cancer, and inherited and acquired thrombophilias.
What are some causes of vascular injury?
Causes of vascular injury include limb trauma including surgery, foreign bodies such as IV cannulae and pacemaker wires, sepsis, bacteria and toxins, previous DVT, and May Thurner Syndrome.
What is venous thromboembolism (VTE)?
Venous thromboembolism (VTE) is the process of blood clot formation in the veins. It includes deep vein thrombosis (DVT) and pulmonary embolism (PE).
What are the common clinical presentations of DVT?
Unilateral calf swelling, heat, pain, redness, and hardness. However, DVT can be asymptomatic or without any signs.
What is the commonest site of DVT?
The leg, particularly the calf (popliteal and tibial veins) and the thigh (femoral and iliac veins).
What are the differential diagnoses of DVT?
Baker’s cyst, cellulitis, muscular pain. A detailed history to determine any risk factors is key to differentiating DVT from other conditions.
What is the investigation of choice for DVT?
Doppler ultrasound, which is quick, safe, and provides real-time 2D images. Colour Doppler (Duplex) can show the direction and velocity of blood flow, and thrombosed veins are non-compressible. A D-dimer test can be useful to rule out DVT if the probability is low. Contrast venography is rarely required, but can be useful in extensive disease or to look for anatomical malformations.
How is DVT managed?
Treatment usually involves anticoagulation with heparin or low-molecular-weight heparin (LMWH), followed by warfarin or direct oral anticoagulants (DOACs). Compression stockings can be used to reduce swelling and prevent post-thrombotic syndrome. In severe cases or if anticoagulation is contraindicated, a filter can be inserted into the inferior vena cava to prevent pulmonary embolism.
What is D-dimer and how is it used in the diagnosis of DVT/PE?
D-dimer is a breakdown product from fibrin, the fibrous mesh component of blood clots. It is only present when the coagulation system has been activated and is elevated in venous thromboembolism. A D-dimer test is very sensitive and can be used to rule out DVT/PE if low probability. However, it is not very specific, and a positive test is not diagnostic. In cases of high clinical probability, a D-dimer test should not be used.