Thrombosis Flashcards
What is the preferred anticoagulant for individuals with triple-positive antiphospholipid antibody syndrome (APS)?
Warfarin is the oral anticoagulant of choice for triple-positive APS, as DOACs have shown a high risk of breakthrough thrombosis.
Why is warfarin preferred over DOACs in triple-positive APS?
The TRAPS study (Trial of Rivaroxaban in Antiphospholipid Syndrome) showed an unacceptably high number of breakthrough thromboses in APS patients treated with DOACs compared to warfarin
Patients receiving thrombolysis must be monitored very closely.
Oozing from line sites and elevation of D-dimers simply indicate that thrombolysis is occurring, and the oozing can be managed with local pressure.
Reduced fibrinogen and platelet counts are expected and can be replaced with cryoprecipiate and platelet transfusions.
A drop of hemoglobin greater than 2 g/dL in a 24-hour period indicates excessive bleeding, so thrombolysis should be discontinued to assess and correct the bleeding.
progression of thrombosis , heparin-induced thrombocytopenia (HIT) after surgery on UFH
Discontinue unfractionated heparin and initiate bivalirudin.
Thrombolysis is contraindicated given the recent major surgery.
Homozygous protein C deficiency
A severe inherited prothrombotic state must be considered for any infant presenting with neonatal purpura fulminans.
ileofemoral venous thrombosis , no FH , no risk factors.next step in management
Anatomic abnormalities such as May-Thurner syndrome (narrowed left iliac vein) and ileofemoral venous thrombosis atresia and abnormalities must be considered for a patient with this presentation and lack of other obvious risk factors.
An inherited thrombophilia (probably a major one such as protein C or protein S deficiency) should also be considered for this patient but testing should be performed at a later time. Protein C and Protein S are likely to be decreased due to consumption at the time of presentation because of the extensive nature of this patient’s thrombosis.
thrombophilia workup
Defects that have been strongly associated with increased risk of VTE include:
- Factor V Leiden mutation
- Prothrombin 20210 mutation
- deficiencies in Protein C, Protein S, or antithrombin.
- Antiphospholipid antibodies is also performed, but in patients who have experienced a VTE, because this is an acquired rather than an inherited thrombophilia.
Factor V leiden
FVL is the most common inherited thrombophilia, occurring in 5% of Caucasians and 1% to 2% of other ethnic groups.
FVL is a mutant form of coagulation factor V, which renders factor V insensitive to actions of protein C, a natural anticoagulant.
Heterozygous FVL increases the risk of VTE approximately fourfold. However, the risk of arterial thrombosis is much lower. It is a mild thrombophilia, and 95% of patients with heterozygous FVL never develop VTE. Guidelines do not recommend anticoagulation during pregnancy or post-partum for asymptomatic women with heterozygous FVL. However, current guidelines still recommend that progestin-only contraceptives be used as first-line therapy for such patients, with estrogen-only considered in special circumstances or when progestin-only contraceptives are not efficacious.
what can lead to low protein C/S ( falsely low) ?
Newborns have naturally low levels of protein S. Warfarin also lowers protein C and protein S activity. Pregnancy causes low protein S levels. Acute thrombosis also lowers the levels of all natural anticoagulants.
Lupus anticoagulant
The LA is characterized by a prolonged PTT that does not correct on 1:1 mixing with normal plasma.
The LA is caused by an antiphospholipid antibody that binds the phospholipid in the PTT.
Excess phospholipid neutralizes the antibody and allows the reaction to proceed.
right subclavian vein thrombosis anatomic cause?
thoracic outlet syndrome. Thoracic outlet syndrome involves compression of the subclavian vein by the cervical rib. Activities such as pitching cause repeated trauma to the vein, resulting in thrombosis
