Exam 3 - The Bleeding Patient Flashcards

1
Q

what is involved in primary hemostasis?

A

involves the interactions between damaged vessels & platelets

forms initial unstable platelet plug

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2
Q

what is involved in secondary hemostasis?

A

results in formation of thrombin to stabilize the platelet & enzymatic reactions activate coagulation factors

stabilizes the platelet plug

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3
Q

what is fibrinolysis responsible for? what does it prevent?

A

responsible for normal degradation of the clot

prevents total occlusion of each injured vessel

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4
Q

what are the general steps of primary hemostasis?

A
  1. injury to a vessel wall
  2. vasoconstriction
  3. platelet adhesion to subendothelium
  4. vWF assists
  5. platelet aggregation to form a plug
  6. phospholipid surface is provided for coagulation enzyme complexes
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5
Q

what is the common signalment of animals with bleeding disorders?

A

more common in dogs than cats

  • inherited coagulopathies more common in juveniles & certain breeds
  • ITP more common in certain breeds
  • neoplasia more likely in older patients
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6
Q

how should collecting samples be performed for a bleeding patient for diagnostic tests?

A
  • collect sample prior to therapy if possible
  • atraumatic venipuncture on a peripheral vein
  • pressure wrap for 5 minutes after
  • no cystocentesis!!
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7
Q

why run a PCV & total protein on a bleeding patient?

A

assess for anemia

low PCV & TP = acute blood loss

low PCV & normal TP = hemolysis or bone marrow disease

check color of plasma for more clues

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8
Q

what is indicated if the patient has a low PCV & TP? what about a low PCV & normal TP?

A

low PCV & TP = acute blood loss

low PCV & normal TP = hemolysis or bone marrow disease

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9
Q

why should a blood smear be performed on all patients with a bleeding disorder?

A

manual platelet count!!!!!

look at RBC morphology, parasites, etc

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10
Q

what is normal when looking at platelets on a blood smear?

A

11-25 platelets/HPF is normal with each platelet = 15,000/uL

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11
Q

what is a normal BMBT time?

A

<4 minutes

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12
Q

why do a BMBT?

A

crude test made with a controlled incision to assess the formation of the initial platelet plug

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13
Q

why run a PT & PTT on a bleeding patient?

A

evaluate secondary hemostasis

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14
Q

what does PT evaluate? what about PTT?

A

PT - extrinsic & common pathways

PTT - intrinsic & common pathways

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15
Q

what is a significant result on PT/PTT tests?

A

> 20% increase from reference interval

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16
Q

what is included in the extrinsic pathway?

A

factor VII

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17
Q

what is included in the common pathway?

A

X, V, II, & I

18
Q

what is included in the intrinsic pathway?

A

XII, XI, IX, & VIII

19
Q

vitamin K is essential for what clotting factors?

A

II, VII, IX, & X

20
Q

what clotting factors aren’t produced in the liver?

A

VIII & vWF

21
Q

what are 4 general disorders of primary hemostasis?

A
  1. vascular wall abnormalities - vasculitis
  2. von willebrand’s disease
  3. quantitative platelet disorder
  4. qualitative platelet disorders
22
Q

what disease processes are included in vascular wall abnormalities?

A

immune-mediated (primary or secondary) or infectious

23
Q

what disease processes are included in quantitative platelet disorders?

A
  1. platelet destruction
  2. decreased platelet production
  3. sequestration
  4. consumption
24
Q

what are 6 general categories of diseases causing secondary hemostasis?

A
  1. vitamin k antagonist rodenticide toxicity
  2. vitamin k deficiency
  3. liver dysfunction
  4. inherited coagulation factor deficiencies
  5. disseminated intravascular coagulation
  6. drug toxicity
25
how long can it take for interstitial fluid to equilibrate in bleeding patients?
2-24 hours
26
how does iron-deficiency anemia generally start?
regenerative & then becomes non-regenerative
27
how is iron-deficiency anemia characterized?
microcytic, hypochromic - thrombocytosis is common chronic, external blood loss - usually from chronic gi bleeding (hookworms, neoplasia, drugs, paraneoplastic syndrome, IBD)
28
what diagnostics should be run if you suspect iron-deficiency anemia?
fecal float urinalysis abdominal ultrasound maybe FNA
29
what are 3 general mechanisms in which anemia can be classified?
1. blood loss 2. hemolysis 3. impaired RBC production
30
what are 3 important natural inhibitors of blood coagulation?
1. antithrombin 2. protein c 3. tissue factor pathway inhibitor
31
what can you use blood pressure measurements for in the bleeding patient?
hypovolemia - associated with hypotension epistaxis - associated with hypertension
32
how is anemia severity characterized based off of PCV in dogs & cats?
dogs mild - 30-36% moderate - 18-29% severe - <18% cats mild - 20-24% moderate - 15-19% severe - <14%
33
at what RBC parameter does spontaneous bleeding occur?
<30,000/uL
34
what may be seen on rbc morphology on blood smear supportive of a bleeding problem?
schistocytes
35
T/F: anemia due to hemorrhage starts of as non-regenerative & then becomes regenerative
true
36
what is a BMBT used for?
assess for disorder of primary hemostasis after platelet count has been confirmed to be adequate
37
what is a normal BMBT time for cats?
<2 minutes
38
what is fibrinogen?
acute phase protein synthesized in the liver - coagulation factor II
39
what can cause hypofibrinogenemia?
liver dysfunction, consumption (DIC or sepsis), congenital disorder, or massive blood transfusion
40
why does iron-deficiency anemia occur?
chronic blood loss depletes bone marrow iron stores over time