Hematology Flashcards
Thrombus
Blood clot
Embolus
Blood clot on the move
Embolism
Embolism that gets stuck in a blood vessel
Arterial thrombosis
Often caused by atherosclerotic lesions on arterial endothelium and usually consists of a platelet-rich clot (white clot).
Venous thrombosis
Often triggered by blood stasis or inappropriate activation of the coagulation cascade and usually consists of a fibrin clot (red clot).
Platelet aggregation inhibitors
(antiplatelet drugs) prevent platelet clots.
Two types of PCIs
Balloon angioplasty & stenting
PCI
Percutanteus coronary intervention
Thrombin inhibitors and vitamin K antagonist
(anticoagulants) prevent fibrin clots.
Indications for Anticoagulants
deep vein thrombosis (DVT) prophylaxis and treatment and pulmonary embolism (PE) prophylaxis and treatment.
Primary Adverse Reactions: Antiplatelet and anticoagulant medications
Bleeding, such as hemorrhagic stroke or GI hemorrhage.
COX-1 inhibitor
Inhibits thromboxane A2 production to decrease platelet aggregation. Ex. aspirin.
ADP Inhibitors
Inhibit adenosine diphosphate’s involvement in stimulating platelet aggregation. Examples - Clopidogrel, prasugrel; ticagrelor, ticlopidine
GP IIb/IIIa Blocker - tirofiban based on the venom of an Asian viper
Physically block glycoprotein IIb/IIIa receptors to prevent fibrinogen, etc. from cross-linking platelets during platelet aggregation. Examples - abciximab, eptifibatide, and tirofiban
Antiplatelet / vasodilators
dipyridamole – coronary vasodilator - Used in combination with aspirin or warfarin to prevent thrombo- embolism in patients with a prosthetic heart valve. Cilostazol – peripheral vasodilator - Used for intermittent claudication.
Direct Thrombin Inhibitors
Unfractionated heparin, bivalirudin and lepirudin. Directly bind to and inhibit thombin to prevent it from converting fibrinogen to fibrin.
Indirect Thrombin Inhibitors
low-molecular-weight heparins (dalteparin, enoxaparin and tinzaparin), apixaban, fondaparinux and rivaroxaban. Directly bind to and inhibit Factor Xa to prevent it from converting prothrombin to thrombin.
Vitamin K antagonist drug
warfarin
Vitamin K antagonist action
Directly interferes with the function of vitamin K and inhibits the synthesis of clotting factors II (prothrombin), VII, IX and X in the liver.
Endogenous fribrinolytic system
tissue plasminogen activator (tPA) and urokinase convert plasminogen to plasmin.
Plasmin
degrades fibrin and dissolves fibrin clots, thus allowing blood flow to resume
Thrombolytics
recombinant versions of tPA and urokinase which are used to treat acute myocardial infarction, acute ischemic stroke and pulmonary embolism.
Clot busters
Thrombolytics; breaks up bad clots AND good clots that are preventing bleeding
Aminocaproic acid
inhibits plasminogen’s activation to plasmin to control hemorrhage in fibrinolytic disorders
Tranexamic acid
Tranexamic acid has the same mechanism as aminocaproic acid and is used for bleeding prophylaxis in some hemophilias.
Protamine
binds to and neutralizes unfractionated heparin and LMWH to treat heparin/LMWH overdose
Vitamin K
reverses warfarin’s inhibition of clotting factor synthesis to treat warfarin overdose
Anemia definition
A below-normal plasma hemoglobin concentration. Typically due to a decreased number of circulating red blood cells or an abnormally low total hemoglobin content per unit of blood volume.
Causes of anemia
Causes include chronic blood loss, bone marrow abnormalities, increased hemolysis, toxic effects of some medications and dietary deficiencies.
Dietary requirements for normal RBC production
Iron, folic acid and vitamin B-12 (cyanocobalamin)
Iron deficiency
results from a negative iron balance due to depletion of iron stores as occurs with acute or chronic blood loss and/or inadequate intake or absorption of iron in food or supplements.
Hypochromic anemia
RBCs are pale
Microcytic anemia
RBCs are smaller than normal
Tx for hypochromic/microcytic anemia
Iron supplementation
Folate deficiency
associated with an increased demand in pregnancy and lactation, poor absorption due to some small intestine conditions, alcoholism and exposure to drugs such as methotrexate and trimethoprim
Megaloblastic anemia
RBCs are larger than normal due to folate deficiency or B-12 deficiency
Megaloblastic anemia tx
Vitamin B-12 and folic acid are both required for other megaloblastic anemias.
Cyanocobalamin (vitamin B-12) deficiency
typically associated with decreased absorption due to inadequate intrinsic factor production by gastric parietal cells, bariatric surgery and nonspecific malabsorption syndromes.
pernicious anemia
Type of megaloblastic anemia due to inadequate intrinsic factor
Pernicious anemia tx
Vitamin B-12 supplementation
Erythropoietin
glycoprotein hormone that is produced in the kidneys. It regulates red blood cell proliferation and differentiation in the bone marrow
Erythropoietin Uses
Recombinant versions are used to treat anemia caused by end-stage renal disease, HIV infection and cancer
Sickle cell disease
inherited red blood cell disorder in which RBC’s contain abnormal hemoglobin S that causes them to dehydrate and become hard and sticky and to take on the shape of a farmers’ sickle.
Sickle cell pain crisis
Sickle cell disease can cause “sickle cell pain crisis” and can damage blood vessels and eventually major organs.
Hydroxyurea
increases the amount of hemoglobin F in RBC’s and protects them from the harmful effects of hemoglobin S.
Pentoxifylline
acts by increasing RBC flexibility and reducing the viscosity of the blood thereby improving blood flow and tissue oxygenation.
