Thrombophilias (Self-made, INC) Flashcards
What is Virchow’s triad?
- Stasis
- Vessel Wall Injury
- Hypercoagulability
What is the pathophysiology behind increased thrombosis risk during infection and inflammation?
- Infection leads to release of procoagulants.
- Inflammation causes endothelial cell damage, which can activate leukocytes, chemokine release, TNF, etc.
What is thrombophilia more closely associated with in terms of thrombosis etiology?
It typically precedes venous thrombosis, but not arterial.
What inherited thrombophilia puts someone most at risk for DVT?
Factor V Leiden
What is the diagnostic test for Factor V Leiden?
APC test.
Lack of change when Activated Protein C is added = Factor V Leiden
What is the underlying pathophysiology of Factor V Leiden?
- Increased coagulation due to slow inactivation of F5a.
- Decreased AC due to lack of cleavage product which impairs APC.
What is the gold standard for detecting inherited thrombophilias?
DNA Testing
What is the underlying physiology of Prothrombin gene mutations?
Increased plasma prothrombin levels.
What is the Protein C & S mnemonic?
Clot Stoppers.
AC effect.
What are patients with Protein C deficiency most commonly susceptible to?
Warfarin-induced skin necrosis
What is the treatment protocol for warfarin-induced skin necrosis?
- Stop warfarin
- Start Vit K, heparin, Protein C concentrate/FFP
What factors does Protein C deficiency mainly affect?
- F8
- F5
What are the usual coag studies for a patient with homozygous Protein C deficiency? Heterozygous?
- Heterozygous: Normal
- Homoygous: similar to DIC, elevated aPTT and PT, low fibrinogen, and thrombocytopenia.
What natural condition can lower Protein S levels?
Pregnancy or those on OCPs.
How does antithrombin III deficiency typically manifest?
Spontaneous DVT or mesenteric vein thrombosis or related to pregnancy/surgery.
What part of pregnancy puts a patient most at risk for thrombosis?
Puerpium
Where is a DVT most common in a pregnant woman? Why?
DVT most commonly occurs in the left lower extremity due to crossing of the right iliac artery OVER the left iliac vein.
What findings are typically associated with suspicion of APS?
- SLE
- Multiple miscarriages
- Thrombotic events
- Livedo Reticularis
- Libman-Sacks endocarditis
What congenital heart defects predisposes someone to DVT?
- PFO
- ASD
What clinical findings suggest DVT?
- Swelling, pain, and discoloration only in the involved extremity.
- Calf tenderness or along deep medial thigh veins.
- Potentially warm/erythematous over thrombosis.
What is the most specific clinical finding for DVT?
Unilateral leg edema > 3m below tibial tuberosity.
What Well’s score is high probability for DVT? PE?
- DVT: 3+
- PE: 4+
What is the primary diagnostic test for DVT?
Compression Venous US w/ Doppler.
What is the primary diagnostic test for a PE?
CTPA
CT Pulm Angio
V/Q scan works as well.
What is the first-line treatment for DVT?
- Heparin + Warfarin
- DOAC alone
When should an IVC filter be considered for DVT?
- CI to AC or high risk of proximal vein thrombosis/PE.
- Recurrent thromboembolisms despite AC.
What are the initial screening tests for a patient with suspected hypercoagulability?
- Antithrombin
- Protein C & S
- Factor V Leiden
- Prothrombin gene mutation
- APS antibody
How can warfarin and heparin influence screening tests for thrombophilias?
- Warfarin lowers Protein C & S levels (Vit K dependent)
- Heparin reduces antithrombin levels.
What is the general starting dose for warfarin?
5mg
