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2) Hemostasis, Exam 2 > Section 4 > Flashcards

Section 4 Flashcards

1
Q

What is Hereditary Hemorrhagic Telangiectasia?
How does it effect coagulation?

A
  • Vessel walls are reduced to a single layer of endothelial cells and inadequate support structures resulting in fragile vessels.
  • Telangiectasias are dilated superficial vessels that blanche with pressure; unlike petechia.
  • Bleeding occurs: epistaxis, GI tract, UG tract, and possible in any organ.
  • Since this type of disorder tends to bleed easily due to the damage of the vessel wall, we can assume that blood vessels are more fragile it’s harder for vessels to stay intact. Thus more work on the coagulation cascade.
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2
Q

What is Ehlers-Danlos Syndrome?
How does it affect coagulation?

A
  • Ehlers-Danlos Syndrome is genetic disorder that is manifested by hyper extensible skin, hyper mobile joints, joint laxity, fragile tissues, and a bleeding tendency, primarily subcutaneous hematoma formation.
  • This is related to coagulation, for this syndrome is a collagen disorder. In the adhesion process the vWf does not stick to the collagen. Thus platelets cannot activate and clots cannot be formed.
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3
Q

What is Allergic and Drug-Induced Purpuras?
How does it affect coagulation?

A
  • Autoimmune vascular injury or Drug causes development of antibody to vessel walls.
  • antibodies or drugs can deposit in the tissues and cause damage to the vessel walls, which can prone for bleeding to occur, activating the coagulation cascade.
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4
Q

What is Henoch-Schonlein Purpura?
How does it affect coagulation?

A
  • This condition usually, a child following upper respiratory infection, has IgA deposits in vessels. The damage of the vessels causes a rash, abdominal pain, joint pain, proteinuria/hematuria.
  • The damage vessels activate the coagulation cascade from further bleeding.

There is a small percentage of people who advance to renal disease.

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5
Q

What is Scurvy?
How does it affect coagulation?

A
  • Scurvy is a vitamin C deficiency that decrease synthesis of collagen and in result can weaken the capillary walls.
  • Not having enough collagen made, makes it difficult for the coagulation cascade to it’s part and prevent further bleeding from occurring.
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6
Q

What is Senile Purpura?
How does it affect coagulation?

A
  • Senile Purpura is seen as a common, benign condition characterized by the recurrent formation of purple bruises on the extensor surfaces of forearms and back of hand.
  • This is usually seen in the elderly
  • This is due to the loss of collagen and subcutaneous fat/ elastic fibers to support for small blood vessels.
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7
Q

Define Platelet disorders

A

disorders of platelet function or platelet numbers

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8
Q

Describe the defect in Bernard-Soulier Syndrome:

A
  • defect - lack of glycoprotein Ib on platelet.
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9
Q

What are the laboratory tests and expected results used in diagnosing Bernard Soulier?

A
  • Bleeding time or PFA is increased
  • Platelets are decreased
  • large platelets are seen
  • Platelet aggregation is still happening, but not with ristocetin
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10
Q

What is the defect in von Willebrand’s disease?
What is the differences between Type I, II, III, and Plt type?

A
  • defect is low levels/ not enough of von Willebrand factor, thus the blood doesn’t clot properly
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11
Q

What is Type I von Willebrand disease?

A
  • Most common type
  • decreased amount of all multimers
  • possibly due to abnormal reals from the epithelial cells
  • structure is normal

–
- People may not have symptoms.
- If they have symptoms, those symptoms are mild
- low levels of von Willebrand factor in their blood.
- (vWF is divided into pieces called multimers)

  • VIII low or normal
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12
Q

What are the laboratory finding of Type I von Willebrand disease?

A
  • PT - normal
  • APTT - increased ( due to decrease in factor VIII)
  • PFA - increased (no longer recommended )
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13
Q

What is Type II von Willebrand disease?

A
  • decreased in high M.W. multimers
  • Possibly due to inability to stabilize large multimers
  • VIII Low/Normal
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14
Q

What is Type III von Willebrand disease?

A
  • Most severe
  • All Multimers are absent
  • Possibly due to reduced synthesis or rapid breakdown at sites of synthesis
  • VIII very low
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15
Q

What is Platelet Type von Willebrand disease?

A
  • GP Ib has increased affinity for vWF
  • Platelets agglutinate and are removed
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16
Q

For von Willebrand factor antigen (vWF: Ag):

  • discuss the principle
  • list the factors/components/reagents
  • state reference range
  • interpret results
A
  • Principle: look at von Willebrand factor antigen. These tests are looking at whether or not vWF is present.
    1. Quantitate plasma vWF through ELISA, Chemiluminescence immunoassay, or Automated method utilizes latex particles
    2. Separate multimers on basis of molecular size through Agarose gel electrophoresis or crossed immunoelectrophoresis.
  • interpretation:
    1. Quantitate plasma vWF detects if vWF is there or not.
    2. detects if multimers are there or not.
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17
Q

For von Willebrand factor Activity - Ristocetin co-factor (vWF: RCo:

  • discuss the principle
  • list the factors/components/reagents
  • state reference range
  • interpret results
A
  • Principle: Uses patient’s plasma and donor pleas.
    -Uses a platelet aggregometer
    -Measures the ability of Patient’s plasma vWF to agglutinate Donor platelets in the presence of Ristocetin.
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18
Q

For von Willebrand factor multimer analysis

  • discuss the principle
  • list the factors/components/reagents
  • state reference range
  • interpret results
A
  • a method for analyzing the concentration and distribution of vWF multimers that are present in plasma
  • Method name ( Agarose Gel/Electrophoresies )
    -Interpret: in normal plasma, vWf multimers appear as a series of banks separated by the mass of 2 subunits. Higher resolution gels reveal the presence of three bands with comprising each multiuser ( a major band with leading and trailing sub-bands), the result of proteolytic cleavage in the circulating blood.
  • there are no clear reference ranges for vWF multimer analysis - for it’s primarily a qualitative test.
  • look at the VWD Type spreadsheet
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19
Q

Discuss the laboratory tests (include expected results) used in diagnosing classic (Type I) von Willebrand’s disease

A
  • PT is normal
  • APTT is increased, due to decrease in factor VIII
  • PFA is increased (no longer recommended )
  • Other specialized testing to help distinguish types
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20
Q

Differentiate the platelet aggregation patterns seen in von Willebrand’s, Bernard-Soulier and Glanzmann’s.

A
  • Von Willebrand’s will have platelets aggregate in blood smears.
  • In Bernard-Soulier, platelets do not aggregate in response to reistocetin even after adding normal plasma, but they do have normal aggregation in response to adenosine diphosphate, epinephrine, and collagen.
  • Glanzmann’s Throbasthenia is the opposite of vW disease and BS
  • can do agglutination but they cannot aggregate
  • defect is platelets lack GP IIb and IIIa. Lab finding are normal except PFA is increased.
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21
Q

Discuss how von Willebrand’s can be differentiated from Bernard-Soulier

A

Add normal donor plasma to patient platelets and it will correct von Willebrand’s, but Bernard-Soulier will not.

22
Q

Discuss why 1-deamino-8-d-arginine vasopressin (DDVAP) is used in the treatment of von Willebrand’s disease

A
  • induces body to release stored vWF
  • best for Type I
23
Q

Discuss how Waldenstrom’s macroglobulinemia and multiple myeloma can cause bleeding tendencies

A
  • Igs coating platelets an collagen fibers
  • affecting the platelets by causing adhesion issues
24
Q

Discuss how aspirin and ibuprofen affect platelet function

A
  • Aspirn inhibits cyclooxygenase, which is needed for TXA2 production.
  • Thus keeps platelets from aggregating.
  • Ibuprofen will block cyclooxygenase, which is needed for TXA2 production
  • Temporary affect on platelets for 24 hours.
25
Q

Discuss how platelet antibodies affect platelet number and/or function

A
  • Antibodies attack platelets and cause a low platelet count
26
Q

Describe the defect in Glanzmann’s Thrombasthenia

A

The defect is platelets lack GP IIb and IIIa

27
Q

Discuss the laboratory tests (include expected results) used in diagnosing Glanzmann’s.

A

-PFA is increased
- PT is normal
- APTT is normal
- Platelet count is normal
- Platelet aggregation is normal only w/ Ristocetin

28
Q

Describe the defect in the storage pool disease: Hermansky-Pudalk Syndrome

A
  • platelet dense granule deficiency
  • dilation of canicular system on plt surface
  • Swiss cheese platelets (electron microscope only)
  • Results in deficient release rxn
29
Q

Describe the defect in the storage pool disease: Gray Platelet Syndrome

A
  • Marked decreased in Platelet Alpha granules
  • Hypo or granular platelets
30
Q

Describe the defect in the storage pool disease: Wiskott Aldrich Syndrome

A
  • Micro platelets
  • Decreased alpha and dense granules in platelets
  • Plt sequestration - decreased platelets numbers
  • recurrent infections - B and T cell dysfunction (serum IgM decreased)
31
Q

Describe the defect in the storage pool disease: Chediak-Higashi

A
  • Platelets lack normal dense granules
  • abnormality
32
Q

Define thrombocytopenia

A
  • Decrease in the number of platelets in the peripheral blood to less than the reference interval; usually less than 150, 000/uL.
33
Q

Discuss four pathophysiological causes for thrombocytopenia (section 3 notes)

A
  • decreased production leads to decreased IPF values
  • increased platelet destruction and increase IPF values
34
Q

Discuss 2 general categories of causes of decreased platelet production

A
  • Congenital hypoplasia
    –> Lack of adequate bone marrow megakaryocytes.
    –> falconi syndrome (low levels of rbcs, wbcs, and platelets

–> Wiskott - Aldrich (platelet sequestration - platelets are removed from the circulation and are not destroyed. Immunodeficiency in males (T and B cells function )

–> May Hegglin (ineffective thromoboiesis w/ large bizarre platelets

  • Acquired hypoplasia
    –> destruction of cells in the bone marrow, thus destruction of platelets
    – This can be caused by irradiation, drugs, ethanol, early aplastic anemia, pernicious anemia and folate deficiency, viruses, bacterial infection, malignancies, myelodyplastic syndromes.
35
Q

List 3 causes of congenital platelet hypoplasia

A

–> falconi syndrome (low levels of rbcs, wbcs, and platelets

–> Wiskott - Aldrich (platelet sequestration - platelets are removed from the circulation and are not destroyed. Immunodeficiency in males (T and B cells function )

–> May Hegglin (ineffective thromoboiesis w/ large bizarre platelets

36
Q

Discuss the laboratory features seen in May-Hegglin anomaly

A
  • ineffective thrombopoiesis w/ large bizarre platelets
  • Dohle like bodies
37
Q

List 9 causes of acquired platelet hypoplasia

A
  • irradiation
  • drugs
  • ethanol
  • early aplastic anemia
  • pernicious anemia and folate deficiency
  • viruses
  • bacterial infections
  • malignancies
  • myeloodyplastic syndromes
38
Q

Define Idiopathic thrombocytopenia purpura (ITP), include the most likely processed involved.

A
  • Mucocutaneous bleeding secondary to thrombocytopenia caused by a platelet-specific autoantibody that shortens platelet life span.
  • Acute ITP occurs more often children, whereas chronic ITP occurs more often in middle aged adult, more commonly in women than in men
39
Q

Discuss the most common laboratory findings in ITP.

A
  • PLT count often <20,000
  • BM - megakaryoctye hyperplasia (platelets are being destroyed and the bone marrow is working)
  • Bleeding time or PFA is increased
  • Deficient clot retraction
40
Q

Discuss the differences in chronic and acute ITP

A

Chronic:
- most 20-50 years
- fluctuating course
- bleeding episodes (days or weeks)
- spontaneous remissions (uncommon)
- may be seen as an early manifestation of AIDs

Acute:
- most in kids
- most have history of infection 2-21 days previous (most viral)
- sometimes occurs after immunization
- usually self limiting (80% spontaneous remission

41
Q

Discuss the mechanism(s) of drugs induced immune thrombocytopenia

A
  • a true auto-Ab develops that is not dependent on the presence of the drug
  • Example: Hapten - linkage of drug to platelet, then ab forms
  • Drug - ab complex attaches to platelet
42
Q

Discuss the mechanism(s) by which heparin can cause thrombocytopenia

A

Heparin - associated thrombocytopenia (HAT)
- Direct non-immune mediated plt activation
-not associated with risk of thrombosis ( blood clots block your blood vessels)

Heparin- induced thrombocytopenia (HIT):
- Case: patient presents with thrombosis
- patient is put on heparin
- within 7 days platelet count drops
- develops antibody to PF4 - heparin complex
- subsequent fall in the plt count
-effect of unfractionated heparin therapy in which antibodies to heparin platelet factor 4 complex develop. The antibody and target antigen complex bind platelet Fc receptors and activation platelets causing thrombocytopenia. Associated venous and arterial thrombosis can lead to amputation and death.

43
Q

Describe the differences between HAT, HIT, and HITTS

A

HAT (Heparin-associated thrombocytopenia ): basically a non-immune response to heparin therapy —> platelet activation. Not associated with risk of thrombosis

HIT ( Heparin-induced thrombocytopenia): basically pt had a thrombosis and they were put on heparin, but that made it trigger the PF4 and activate the coagulation cascade, leading to unwanted thrombosis and less platelets are in the system.

HITTS: a sub group of patients experience PLT counts as low as 20 x 10 ^3/mm^3 as well as thrombosis. This initiates the coagulation cascade

44
Q

Describe the principle of the Heparin Induced Platelet Aggregation test (HIPA)

A
  • Test for the presence of Heparin-induced Ab in patient plasma. (Patient must be off heparin for 8 hours)
  • Use Platelet Aggregometer
  • Normal Donor Plts + Pt. PPP + dilution of heparin
    –> If AB present in patient plasma the plus will aggregate
  • Negative control: Donor Plts + Pt. PPP + saline
45
Q

Discuss the pathophysiology of neonatal alloimmune thrombocytopenia

A
  • The mother produces a platelet specific antibody and that attacks the baby’s when expose to baby’s blood.
  • Rh antigen
46
Q

Discuss why ITP can cause problems in pregnant women?

A
  • If a women with ITP becomes pregnant, her platelet count may drop in the third trimester, exacerbating existing symptoms.
  • not actually “auto” - mother has ITP or SLE, commonly develops in pregnancy.
    -Mom’s has the autoimmune disorder, mom’s plt is low, she is at risk at delivery.
    -Baby is at risk if at vaginal birth b/c of cranial pressure.
  • High risk delivery
  • fetal scalp platelet
47
Q

Define HELLP syndrome and describe expected laboratory findings.

A

HELLP Syndrome
- H emolysis
- EL Elevated Liver enzyme
- LP Low Platelet Count

A life-threatening pregnancy complication, considered a variant of preeclampsia. Preeclampisa is when pregnancy induced hypertension in association with either edema or proteinuria after 20 weeks gestation.

Lab findings:
–> Low platelets and schistocytes
- Hemolysis -> Hgb &Hct, LDH, Bilirubin, Haptoglobin
- Hepatic Dysfunction -> AST>48 IU, ALT> 24 IU/L, LDH>164 IU/L

48
Q

Describe the hallmark findings of Thrombotic Thrombocytopenic Purpura (TTP), include laboratory findings.

A
  • abnormally large vonWilliambrand factor
  • Platelet thrombus forms - micro thrombi
  • Appears to results from small platelet aggregates and unusually large vonWillebrand factor that occlude the capillaries in organs.
    –> Auto-antibody against ADMATS13
    –> Rare inherited variant of TTO is caused by ADAMTS13 deficiency

Lab findings:
- Hemolytic anemia with schistocytes and other signs
- Thrombocytopenia (hemorrhage)
-Fluctuating neurological dysfunction
-Fever and PROGRESSIVE renal disease

49
Q

Describe how to distinguish between TTP and Hemolytic Uremic Syndrome (HUS)

A
  • Distinguished from TTP by severity of renal failure and absence of neurologic symptoms.
    -As well, there is often seen organisms such as E.coli in kids with HUS, and there’s acute renal failure.
50
Q

Define thrombocytosis

A

increase in the number of platelets in the peripheral blood to more than the reference interval; usually more than 450,000/ uL.

51
Q

Describe what is meant by reactive thrombocytosis

A

response to blood loss, major surgery, childbirth, tissue, necrosis, inflammatory disease, exercise, etc.

Reactive thrombocytosis is an elevated platelet count (greater than 450k) that develops secondary to another disorder.

52
Q

Describe the pathophysiology and hallmark findings of Essential Thrombocythemia

A
  • Bone marrow increases megakayocytes production, thus platelet count is greater than 600k, even greater than 1 million.
  • Larger masses of platelet aggregates
  • Giant and buzzard form, many small forms also
  • Spontaneous plt aggregation and plt function defects reusing in thrombotic and hemorrhagic complications
  • causes thrombosis. and bleeding issues for plt don’t function properly
    and giant bizarre forms of platelets form.

2) Hemostasis, Exam 2 (5 decks)

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