Clotting Disorders Flashcards
When a clot breaks free it is called an:
embolus
What are the risk factors for atherosclerosis?
Hypertension
Hyperlipidemia
Obesity
Smoking
What are the risk factors for stasis?
Immobilization
Varicose veins
Cardiac dysfunction
What are the risk factors for hypercoagulability?
Trauma/surgery
Carcinoma
Estrogen/postpartum
Thrombotic disorders
What is the most common cause of unexplaned thromboses
Factor V leiden
What is the problem with the factor V gene in Factor V Leiden?
Protein can’t be turned off
What factor cleaves factor V (and can’t cleave it if the mutation is there?
Protein C
Why are PTT and INR not helpful in diagnoses of Factor V Leiden?
PTT and INR will be normal because the protein works fine
Genetic testing is needed
How do you treat Factor V leiden?
Don’t unless there’s a thrombosis, then give anticoagulant for a while
A deficiency in this protein will result in a significantly decreased effect of heparin.
ATIII
What is the result of the mutation in the ATIII gene that causes ATIII deficiency?
Makes LESS ATIII
Homozygotes of ATIII deficiency have this prognosis:
Heterzygotes of ATIII deficiency have this prognosis:
Homozygotes: Will not survive into infancy
Heterozygotes: Half get clots
Along with being an anticoagulant, protein C has these two effects:
Firbinolytic (promotes t-PA), anti-inflammatory (decreased cytokines)
What happens to someone with a Protein C deficiency when given warfarin?
Warfarin induced skin necrosis
What is the role of protein S?
Endothelial cell receptor for protein C
What is requried for diagnosis of protein C deficiency
functional testing
If you give this drug to someone with a protein C deficiency, they will very likely get skin necrosis.
Coumadin
What is purpura fulminans?
A thrombotic state associated with vascular injury, resulting in skin necrosis
How do you treat purpura fulminans?
Give protein C
What is the result of the gene deficiency in which factor II (prothrombin) is the culprit?
Makes TOO MUCH prothrombin
Too much homocysteine results in what vascular effect?
thromboses
What is the most common gene defect for homocysteinemia?
MTHFR: Methylene tetrahydrofolate reductase
What are the other two enzyme defects known for hyperhomocysteinemia?
Methionine synthase
Cystathionine beta synthase
What enzyme is deficient in homocysteinuria?
Trans-sulphuration enzyme
What is the effect of homocysteinuria?
Increased homocysteine in blood and urine
Increased thrombosis, premature artherosclerosis
What dietary deficiency can result in homocysteinemia?
B12/folate deficiency
What are the two distinct toxicities to increased homocysteine levels?
Toxic to endothelium, forms ROS
Interferes with NO, which is a vasodilater and antithrombotic
When a patient has antibodies against phospholipids, what tests are deceitful?
INR is falsely prolonged
PTT/PT reagents bound
DAT test and syphilis tests screwed up
What is different about coagulation in vivo/in vitro for Antiphospholipid antibodies?
Promote coagulation in vivo
Inhibit coagulation in vitro
What are the main results of antiphospholipid antibody syndrome? (5)
Recurrent thrombosis Recurrent spontaneous abortion Increased risk of stroke Pulmonary hypertension Renal failure
What is the more definitive test to find antiphospholipid antibody syndrome
PTT mixing study
