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34 Cards in this Set
- Front
- Back
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vWF is syntesized in ________ cells and ________. it is mainly involved in initiating _______ of platelets to damaged vessel walls.
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endothelial; megakaryocytes
adhesion |
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primary hemostasis = ______ and ______ of platelets; then follows ____ _____, ______, and _____.
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adhesion; activation; shape change; secretion; aggregation
PRIMARY HEMOSTASIS = PLATELET PLUG FORMATION |
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secondary hemostasis = _____ ________.
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blood coagulation - Clots form upon the conversion of fibrinogen to fibrin, and its addition to the platelet plug to make fibrin meshwork
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there are 2 pathways in secondary hemostasis, leading to a common pathway:
______ factor + ____ ("extrinsic") = initiation ____ - ____ - ___ ("intrinsic") = propagation |
tissue; VIIa
XIa-IXa-VIIa |
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distinguish between signs and symptoms of primary hemostasis defects and plasma coagulation (secondary hemostasis) defects
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primary hemostasis =
1) mucocutaneous bleeding (petechiae, epistaxis, menorrhagia, prolonged bleeding after tooth extraction) 2) increased bleeding after aspirin/NSAID intake 3) increased intraop and postop bleeding secondary hemostasis= 1) DEEP bleeding (hemarthrosis - bleeding in joint spaces, soft tissue/muscle hematoma, ecchymoses - bruising) 2) inc bleeding intraop, postop, with dental procedures 3) mucosal, GI/GU bleeding |
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what type of tests can you do for primary hemostasis?
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-platelet count/smear review
-PFA-100 (platelet fxn): screens for qualitative platelet and vWD; requires nL platelet count |
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what are tests you can do for secondary hemostasis?
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1) PT and INR
- tests extrinsic (7) and common pathway factor (10,5,2) - checks for Vit K deficiency (10,9,7,2) - monitors warfarin therapy (affects vit K dependent) 2) PTT - for intrinsic and common pathway factors (12, 11, 9, 8, etc) - monitors heparin therapy |
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which test for secondary hemostasis in a pt that evaluates the conversion of fibrinogen to fibrin?
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thrombin time (not often used for congenital bleeding disorders)
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which factor is NOT screened for by PT or PTT?
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factor 13
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pathophysiology of vWD
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deficiency or dysfxn of vWF --> impaired platelet adhesion to endothelium
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type of vWD that is characterized by homozygous, severe deficiency
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type 3
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type of vWD that is characterized by heterozygous, partial deficiency
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type 1
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most vWD types are autosomal dominant, except type __ and __, which is autosomal recessive
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2N, 3
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laboratory tests of hemostasis to screen for and diagnose von Willebrand disease (and what would you expect)?
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- vW panel (vW activity, vW antigen, factor VIII, vW multimers)
- PFA-100 (will be prolonged) - PTT (will be prolonged if FVIII low) |
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use laboratory tests of hemostasis to screen for and diagnose hemophilia A
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hemophilia A, a deficiency of factor VIII, which is part of the contact factor pathway, results in an abnormally prolonged aPTT test but a normal PT test.
so... - factor 8 dec - prolonged PTT - factor 8 analysis (for inversion of intron 22) |
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tx for bleeding in a pt with von Willebrand dz
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-DDAVP (synthetic analog of vasopressin, which will release vWF from WP bodies in endothelial cells); but not all types of vWD will respond to this so you have to check
-Plasma-derived FVIII/vWF products |
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name some complications of hemophilia A
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CNS bleeding, arthritis, muscle fibrosis
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pt presents with hemarthrosis (joint bleeds), muscle hematomas, and slight mucosal bleeding.
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hemophilia A or B (they show up the same in clinic)
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pt has personal/family hx of bleeding with physical evidence of mucocutaneous bleeding. lab's reveal that vWF activity is well below normal, PFA-100 is prolonged and PTT is also prolonged. dx?
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vWD
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what is the most common coagulation factor deficiency?
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factor VIII deficiency (hemophilia A)
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genetic pattern of vWD, hemophilia A vs. hemophilia B.
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vWD = autosomal dom
HA = x-linked recessive HB = x-linked recessive |
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inversion involving intron 22 is characteristic of what dz?
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hemophilia A (mostly severe cases)
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how do you differentiate Hemophilia B vs. hemophilia A?
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HA = deficiency of factor VIII
HB=deficiency of factor IX |
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what lab tests do you run for hemophilia B?
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-factor IX dec
- prolonged PTT |
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tx options for pt with hemophilia A vs. hemophilia B
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HA - recombinant factor 8 product
HB - recombinant factor 9 product |
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5 yo M, otherwise healthy, is referred by his pediatrician for recurrent epistaxis. He has nosebleeds 2-3 times per month, usually lasting 10-15 min each, bleeds from either nostril. Bruises more easily than his siblings. No excessive bleeding, bruising or swelling with vaccines. No surgical challenges. Family history significant for father who had hemorrhage after tonsillectomy as a child, paternal grandfather and uncles with easy bruising and frequent epistaxis. Physical exam unremarkable except for multiple bruises of varying ages on lower extremities.
What screening tests would you order on this patient? I. CBC with smear review II. PT, PTT, fibrinogen III. von Willebrand panel IV. PFA-100 V. Factor VIII and Factor IX A) III only B) V only C) II and V D) I, II, III, IV E) All of the above |
D. This is not an x-linked recessive disorder. So it’s transmitted through the mother’s side. So this is most likely not hemophilia A or B.
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Lab results are as follows:
CBC is normal with hemoglobin 12.5g/dL (11.5-14.5), platelets 210K/uL (150-450). Smear shows platelets of varying sizes with granules present. PT is 14 sec (12.3-15.0), PTT is 31sec (24-33.8), fibrinogen 299mg/dL (220-440). Von Willebrand panel shows: Factor VIII = 68%, (47-169 ), von Willebrand activity = 25% (54-120), von Willebrand antigen = 47% (56-176), vWF multimer pattern= normal. PFA-100: collagen epi 180 sec (84-183), collagen ADP 120 sec(69-126). The most likely diagnosis at this time would be: A) Mild hemophilia A B) Type 1 von Willebrand disease C) Mild hemophilia A with type 1 von Willebrand disease D) Type 2 variant of VWD E) Platelet functional defect |
B. when you're looking for the type of vWD, know that type 1 is most common. in type 2, the multimer is abnormal.
types 1 and 3 are quantitative defects (where there's low numbers of vWF). type 1 is mild deficiency. it's not type 3 bc he has some vW activity...type 3 would show no activity at all. |
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Lab results are as follows:
CBC is normal with hemoglobin 12.5g/dL (11.5-14.5), platelets 210K/uL (150-450). Smear shows platelets of varying sizes with granules present. PT is 14 sec (12.3-15.0), PTT is 31sec (24-33.8), fibrinogen 299mg/dL (220-440). Von Willebrand panel shows: Factor VIII = 68%, (47-169 ), von Willebrand activity = 25% (54-120), von Willebrand antigen = 47% (56-176), vWF multimer pattern= ABNORMAL. PFA-100: collagen epi 180 sec (84-183), collagen ADP 120 sec(69-126). The most likely diagnosis at this time would be: A) Mild hemophilia A B) Type 1 von Willebrand disease C) Mild hemophilia A with type 1 von Willebrand disease D) Type 2 variant of VWD E) Platelet functional defect |
D. type 2 variant of vWD
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How would you treat bleeding episodes in this patient?
I. Fresh frozen plasma II. Recombinant vWF product III. Plasma-derived Factor VIII product containing vWF IV. DDAVP and/or Stimate, once adequate response is documented V. Aminocaproic acid A) I and II B) II only C) III and IV D) III, IV, V E) All of the above |
D.
fresh frozen plasma is for places that don't have specific plasma derived products. FVIII product is useful for hemophilia A. aminocaproic acid is a anti-fibrinolytic, so it helps your body not break down the clot. so it can be used for menorrhagia, nose bleeding. |
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name the anti-fibrinolytic drug (helps you not break down clot and keep the body clotting) that can be useful for bleeding problems, like menorrhagia or nose bleeding
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aminocaproic acid
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1) A 16 year old female is referred for menorrhagia. Her workup reveals hemoglobin 11g/dL (12-16), platelet count of 250,000/uL (150-450), von Willebrand activity of 27% (54-120), von Willebrand antigen of 45% (56-176), factor VIII activity of 48% (47-169) and a normal vWF multimer pattern. All of the following are appropriate treatment options for this patient except:
A. Aminocaproic acid B. Intravenous desmopressin, once adequate response has been documented C. Intranasal desmopressin (Stimate), once adequate response has been documented D. Plasma-derived factor VIII product containing von Willebrand factor E. Recombinant factor VIII product |
E
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3 year old male is seen for preoperative screening prior to tonsillectomy. He has a history of recurrent epistaxis but no other bleeding symptoms. Family history is negative for known bleeding disorders. Prothrombin time is 13.5 seconds (11.5-14.5), international normalized ratio is 1.0 (0.9-1.1), and activated partial thromboplastin time is 31 seconds (24-33.8). PFA-100 shows closure time with collagen epinephrine of 190 seconds (84-183), and with collagen ADP of 135 seconds (69-126). All of the following could explain these lab results except:
A. aspirin use the day prior to testing B. qualitative platelet defect C. von Willebrand disease D. hemophilia A E. severe thrombocytopenia |
D. hemophilia A would give you an abnormal PTT time (due to factor 8 deficiency)
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A 10 month old boy is referred for easy bruising. His mother reports excessive bleeding after neonatal circumcision and swelling of the thighs after vaccinations. She has also noticed several episodes of swelling of his right knee since he started crawling. On physical exam, he has multiple large ecchymoses on his buttocks, legs and back. Upon further questioning, the mother recalls that her father and her uncle had problems with postoperative bleeding. The patient’s parents deny any personal bleeding history. Evaluation of this patient is likely to reveal all of the following except:
A. prolonged activated partial thromboplastin time (PTT) B. autosomal dominant inheritance C. inversion within intron 22 of the factor VIII gene D. Factor VIII activity <5% (normal 47-169) E. normal prothrombin time |
B. hemophilia is an x-linked recessive; there are 2 clues: passing down father's side and "multiple large ecchymoses"
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All of the following statements are true except:
A. Factor VIII plays a key role in fibrin formation by enhancing the activation of factor X by factor IX. B. When calculating factor replacement dosing, one unit per kilogram body weight of recombinant factor IX product increases factor IX activity by approximately 1%. C. Type I von Willebrand disease often presents with deep bleeding symptoms such as hemarthroses. D. A prolonged PTT can be seen in severe von Willebrand disease. E. The prothrombin time and international normalized ratio are used to monitor warfarin effect, whereas the activated partial thromboplastin time is used to monitor heparin effect. |
C.(Type 2n and type 3 present like hemophilia, but not type 1. they present bc vWF is a carrier for factor 8 and prolong its half-life. and these specific types of vWD will actually cause a deficiency in factor 8 bc they don't last as long in the blood supply)
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