Hemostasis

Question 1

Steps of hemostasis

Answer 1

1. Vasoconstriction
2. Temporary blockage of a break by a platelet plug
3. Blood coagulation - formation of fibrin clot (thrombin converts fibrinogen to fibrin)

Eventually Fibrinolysis (how the clot dissolves)

Question 2

Platelet plug

Answer 2

made of thrombocytes (platelets) - adhesion, activation, aggregation

Question 3

Platelets (thrombocytes)

Answer 3

150-450,000. Thrombocytopenia - low platelets. Thrombocytosis/thrombocythemia - high platelets.

Question 4

Diseases with not enough clot

Answer 4

Hemophilia, thrombocytopenia, DIC, factor deficiency

Question 5

Diseases with too much clot

Answer 5

Factor V Leiden, antiphospolipid, HIT, DVT, protein C or S deficiency

Question 6

S/S of bleeding

Answer 6

tachycardia, hypotension, altered mental status, weak pulses, cool to touch, pallor

Question 7

Pts at risk of bleeding

Answer 7

Condition: cancer, excess ETOH, liver disease, kidney disease, connective tissue disorders, hypothyroidism
Meds: NSAIDs, anti-coagulants, glucocorticoids

Question 8

PT (prothrombin time)

Answer 8

time it takes plasma to clot when exposed to tissue factor (extrinsic) - 11 - 13 seconds

Question 9

INR (international normalized ratio)

Answer 9

measures activity of prothrombin, fibrinogen, some factors. Normal .8-1.1

Question 10

PTT (partial thromboplastin time)

Answer 10

time it takes plasma to clot when exposed to substances that activate contact factors (intrinsic). Normal 30-40 seconds (higher therapeutic range for anticoagulation). Assessed in pts receiving heparin.

Question 11

Causes of thrombocytopenia

Answer 11

Decreased platelet production, increased consumption or both. Ex: liver disease, HIV, meds (antibiotics, estrogen, SSRI), chronic renal failure, cancer

Question 12

HIT

Answer 12

Heparin induced thrombocytopenia - pt develops an allergy to it –> immunity mediated clotting disorder that causes low platelet count

Question 13

ITP/ATP

Answer 13

Immune thrombocytopenia purpura - autoimmune disorder in which lifespan platelet is decreased by antiplatelet antibodies

Question 14

TTP

Answer 14

Thrombotic thrombocytopenia purpura - platelets abnormally clump together due to autoimmune reaction from platelet aggregation leading to inappropriate clotting

Question 15

Embolus

Answer 15

Thrombus that detached from vessel wall and circulating in blood stream

Question 16

Virchow’s triad

Answer 16

Stasis of blood, hypercoagulability, vessel wall injury

Question 17

Hypercoaguable states

Answer 17

Cancer, thrombophilia, inflammatory disease, sepsis, dehydration, COC use, postpartum

Question 18

Endothelial damage

Answer 18

IV drug use, surgery, trauma, IV/central line

Question 19

Stasis risks

Answer 19

Immobility, varicose veins, surgery, long travel, pregnancy, obesity

Question 20

D-dimer test

Answer 20

Checks for fibrin degradation to show theres a blood clot

Question 21

Tx for clotting

Answer 21

Anticoagulants

Question 22

Fibrinolytics

Answer 22

clot buster - degrades fibrin. Used for PE, cardiac arrest, ischemic stroke.