Heme/Coag Flashcards
1
Q
Platelet granules
- Alpha
- Delta (dense)
A
Platelet granules
- Alpha granule
- thromboglobulin
- P-selectin
- PDGF
- PF4
- platelet fibrinogen
- thrombospondin
- VWF
- Delta (dense) granule [Delta’s CASA]
- Ca++
- ATP
- Serotonin
- ADP dense granule -> vasoconstriction
2
Q
Fibrinolysis
- TPA cleaves __ to __
- Plasmin cleaves __into __
Three inhibitors:
- _
- _
- _
A
Fibrinolysis
- TPA cleaves plasminogen to plasmin
- Plasmin cleaves fibrin into fibrin split products
Three inhibitors
- Alpha two antiplasmin inhibits plasmin
- PAI inhibits plasminogen
- TAFI (thrombin activatable fibrinolysis inhibitor) inhibits binding of plasminogen and TPA to fibrin
3
Q
Anticoagulation
- Thrombomodulin
- Activated protein C + protein S (its carrier)
- AT
A
Anticoagulation
- Thrombomodulin
- binds to thrombin to activate protein C
- Activated protein C + protein S (its carrier)
- inhibit FV and FVIII
- AT
- binds to heparin and inhibits conversion of II to IIa
- also inhibits Xa action
- Liver-produced
4
Q
Platelets cell-surface antigens
- The GP (glycoprotein) Ib/V/IX complex:
- receptor for __
- CD__
- The GP IIb/IIIa complex:
- receptor for __
- platelet antigen __ a/w GP IIIa
- __ alleles, __
- Platelet antigens __ a/w GP IIb
- CD41 = __
- CD61 = __
- GP Ia/IIa complex:
- __receptor __
- GP Ic/IIa complex:
- __receptor
- Red cell antigens:
- __
- Class __ MHC antigens
- Passively adsorbed __
A
Platelets cell-surface antigens
- The GP (glycoprotein) Ib/V/IX complex:
- receptor for vWF
- CD42
- The GP IIb/IIIa complex:
- receptor for fibrinogen
- platelet antigen PLA a/w GP IIIa
- 2 alleles, PLA1 and PLA2
- Platelet antigens baka and bakb a/w GP IIb
- CD41 = GP IIb/IIIa
- CD61 = GP IIIa
- GP Ia/IIa complex:
- collagen receptor Bra/Brb
- GP Ic/IIa complex:
- fibronectin receptor
- Red cell antigens:
- ABO, I, i, P, Le (no Rh antigens)
- Class I MHC antigens
- Passively adsorbed IgG and coagulation factors
5
Q
Extrensic Pathway
Intrinsic Pathway
The Common Pathway
A
Extrensic Pathway
- FVII
- tissue injury leads to the release of tissue factor (III)
- FVIIa cleaves factor X to factor Xa
- Xa is capable of activating VII to VIIa
- VIIa capable of activating IX to IXa, so in vivo activation of VII can propel the intrinsic pathway
- major mechanism by which the administration of FVIIa exerts its therapeutic effect
Intrinsic Pathway
- FXII, FXI, FIX, FVIII, prekallikrein, and HMWK (plus calcium and phospholipids)
- endpoint is conversion of factor X to factor Xa
- initiated by the proximity of prekallikrein, HMWK, FXII and FXI to one another and to a negatively charged surface (contact phase)
- early evolutionion (ocean/sand)
- results in conversion of prekallikrein to kallikrein, which activates FXII to FXIIa
- XIIa activates more prekallikrein to kallikrein, establishing a cycle
- activation of FX carried out by the tenase complex (Calcium, FVIIIa, FIXa) on plt surface
- Platelets
- when activated, express an abundance of phosphatidylserine (PS) and phosphatidylinositol (PI) on surface
- facilitate attachment of the tenase complex
- Xa is capable of activating VII to VIIa, thus providing a link with the intrinsic pathway
The Common Pathway
- FX, FII, and fibrinogen
- Xa converts FII (prothrombin) to FIIa (thrombin)
- thrombin converts fibrinogen (I) to fibrin (Ia)
- prothrombinase complex forms on the surfaces of platelets
- anchored by PS and PI
- consists of Va and Xa
- Fibrinogen is composed of pairs of three polypeptides:
- A-α, B-β, γ
- A and B are referred to as fibrinopeptides (FpA and FpB)
6
Q
Control of Coagulation
- Thrombin concentration controlled by:
- __degradation
- __
- Thrombin activation controlled by:
- __
- inactivates thrombin and __
- can be stimulated by __
- __
- __
- __
- thrombin combines with __ on endothelial cell surfaces forming __ complex that converts __ to __
- __ inactivates__, with __as its cofactor
- __
- Plasmin
- primary agent of __degradation
- formed from __which is structurally incorporated into the fibrin clot
- Tissue plasminogen activator (tPA)
- converts __to __
- released from __ following injury
- exposure to __activates tPA
- Plasmin is controlled by:
A
Control of Coagulation
- Thrombin concentration controlled by:
- fibrin degradation
- tissue factor pathway inhibitor (TFPI)
- inhibition of the tissue factor-FVIIa-FXa complex
- Thrombin activation controlled by:
- Antithrombin
- inactivates thrombin and FIXa, FXa, FXIa and FXIIa
- can be stimulated by heparin (basis for therapy)
- α2-macroglobulin
- heparin cofactor II
- α1-antitrypsin
- thrombin combines with thrombomodulin on endothelial cell surfaces forming thrombin-TM complex that converts protein C to activated protein C (APC)
- APC inactivates FVa and FVIIIa, with protein S as its cofactor
- Antithrombin
- Plasmin
- primary agent of fibrin degradation
- formed from plasminogen which is structurally incorporated into the fibrin clot
- Tissue plasminogen activator (tPA)
- converts plasminogen to plasmin
- released from vascular endothelial cells following injury
- mechanisms for fibrin degradation and formation set into motion simultaneously
- exposure to fibrin activates tPA
- Plasmin is controlled by:
- rapid degradation by α2-antiplasmin
- inhibition by plasminogen activator inhibitors (PAI-1 and PAI-2)
7
Q
PLATELET AGGREGATION STUDIES
- Optical density (%)
- w/ aggregation __
- __and __are weak agonists and biphasic
A
PLATELET AGGREGATION STUDIES
- Optical density (%)
- w/ aggregation, less light scattering, lower optical density
- ADP and epinephrine are weak agonists and biphasic
8
Q
Platelet aggregometry
- Pre-analytical
- no aspirin or NSAIDs for __ days
- tubes kept at __ temp (__causes platelet activation)
- test performed within __ hours
- sample of__ (prepared by?)
- sample stirred continuously within a cuvette while being exposed to various agonists
- light transmission through the sample __as aggregation takes place
- optical density __
- Is there spontaneous aggregation?
- adult __% platelet aggregation (__in newborns) in response to platelet agonists:
- __
- biphasic curve (primary and secondary wave of aggregation)
- __
- monophasic curve (primary aggregation only)
- __
- ___
- response with concentration >1.2 mg/mL
- little to no response <0.8 mg/mL
- __
- response follows a short lag
- Monitor release of platelet dense granules (secondary wave) during aggregation
- assay __ using __ assay
A
Platelet aggregometry
- Pre-analytical
- no aspirin or NSAIDs for >7 days
- tubes kept at room temp (cold causes platelet activation)
- test performed within 2 hours
- sample of platelet-rich plasma (slow-centrifugation of whole blood)
- sample stirred continuously within a cuvette while being exposed to various agonists
- light transmission through the sample increases as aggregation takes place
- optical density decreases
- no spontaneous aggregation
- adult >60% platelet aggregation (less in newborns) in response to platelet agonists:
- (AACRE)
- ADP, Arachidonate, Collagen, Ristocetin, Epinephrine
- biphasic curve (primary and secondary wave of aggregation)
- low-dose ADP and epinephrine
- monophasic curve (primary aggregation only)
- high-dose ADP, collagen, ristocetin
- ristocetin
- response with concentration >1.2 mg/mL
- little to no response <0.8 mg/mL
- collagen
- response follows a short lag
- Monitor release of platelet dense granules (secondary wave) during aggregation
- assay secreted ATP using firefly luminescence assay
9
Q
Abnormal aggregometry
- most common cause of abnormal aggregometry is __
- decreased aggregation with arachidonate
- no secondary phase with epinephrine and ADP
- poor response to epinephrine
- response to everything but risotocetin
- poor response to all agents except ristocetin
A
Abnormal aggregometry
- most common cause of abnormal aggregometry is a medication
- decreased aggregation with arachidonate
- aspirin/aspirin-like agents
- no secondary phase with epinephrine and ADP
- storage pool defects and aspirin
- poor response to epinephrine
- myeloproliferative diseases
- response to everything but risotocetin
- von Willebrand disease and Bernard-Soullier syndrome
- poor response to all agents except ristocetin
- Glanzmann thombasthenia
10
Q
A
Response to everything but risotocetin
- von Willebrand disease and Bernard-Soullier syndrome
11
Q
A
Poor response to all agents except ristocetin
- Glanzmann thombasthenia
12
Q
Congenital Platelet Disorders
A
Congenital Platelet Disorders
- Bernard-Soulier Disorder
- Glanzmann thrombasthenia
- May Hegglin
13
Q
___
- What type of problem?
- Defect __ (CD__)
- Can’t bind __
- Thrombocytopenia?
- __PT, PTT, ___bleeding time
- Impaired __ aggregation
- Platelet flow cytometry shows ↓ __
A
Bernard-Soulier
- Adhesion problem
- Defect GPIb/V/IX (CD42)
- Can’t bind vWF
- Large giant platelet w pseudonucleolus
- Thrombocytopenia
- Normal PT, PTT, increased bleeding time
- Impaired ristocetin aggregation
- If you add normal ptls + ristocetin, aggregation will be nl b/c the abnormality is on the patients plt.
- Platelet flow cytometry shows ↓ CD42a, b and d (GPIba, V and IX)
14
Q
___
- __problem
- Plts can’t bind __
- Abnormal __
- Thrombocytopenia?
- Plt aggregation studies?
- Dx: Flow cytometry shows ↓ __
- Differential diagnosis
- _& _
- both defect in__ interactions
- __normal PT/PTT
- __↑PT/PTT
- _& _
A
Glanzmann thrombasthenia
- Aggregation problem
- Plts can’t bind fibrinogen
- Abnormal GP IIb-IIIa
- Normal plt count
- Poor response to all agents except ristocetin
- Dx: Flow cytometry shows ↓ CD41 (GPIIb) and CD61 (GPIIIa)
- Differential diagnosis
- Glanzmanns & Afibrinogenima
- both defect in fibrin:fibrin interactions
- Glanzmann’s normal PT/PTT
- Afibrinogenemia ↑PT/PTT
- Glanzmanns & Afibrinogenima
15
Q
May Hegglin Anomaly
- Mutation
- Inheritance
- Thrombocytopenia?
- PMN function?
A
May Hegglin Anomaly
- Mutation in myosin heavy chain 9 gene
- Autosomal dominant
- WBC inclusion (Dohle-like) + Giant plt
- Thrombocytopenia, but little bleeding
- PMN function is normal
16
Q
Giant Platelets
A
Giant Platelets
Lying about how big your plts are: FIB GAMMMES
- Fechner syndrome
- ITP
- Bernard Soulier
- Gray platelet syndrome
- Alport syndrome
- May Hegglin
- Montreal plt syndrome
- Mediterranean macrothromocytosis
- Epstein syndrome
- Sebastian syndrome
17
Q
Storage Pool Deficiency
- Decreased plt __due to deficiencies in __
- __morphology, __ on EM
- Plt agg studies:
- __
- __ collagen & AA
- __ristocetin
- __ATP:ADP ratio
- 5 Examples of Storage Pool Deficiency
A
Storage Pool Deficiency
- Decreased plt aggregation due to deficiencies in dense/alpha granules
- Normal morphology, no granules on EM
- Plt agg studies:
- No 2nd wave ADP, EPI
- Decreased collagen & AA
- Normal ristocetin
- ↑ ATP:ADP ratio
- 5 Examples of Storage Pool Deficiency (Quebec is Gray, Cold & Wet, never Hot)
- Quebec plt disorder
- Gray platelet syndrome
- Chediak Higashi
- Wiscott Aldrich syndrome
- Hermansky-Pudlak Syndrome
23
Q
vWD Type I
- multimers?
- frequency?
- tests?
- treated w DDAVP?
vWD type 2a and 2b
- Type 2a
- multimers?
- tests?
- treated w DDAVP?
- Type 2b
- multimers?
- tests?
- treated w DDAVP?
- mutation?
Type 3
- inheritance?
- multimers?
- tests?
- treated w DDAVP?
vWF 2M and 2N
- Type 2M
- multimers?
- tests?
- treated w DDAVP?
- Type 2N (Normandy)
- genetics?
- multimers?
- tests?
- treated w DDAVP?
- Frequency
A
vWD Type I
- Low quantity, normal multimers, functionally normal
- Most common type
- Sometimes all tests are normal
- Only type treated w DDAVP
vWD type 2a and 2b
- Type 2a
- Decreased large and medium sized multimers
- Disproportionately low vWF:RCo (quality) relative to vWFAg (quantity)
- Type 2b
- Mutation in exon 28 of VWF that causes increased affinity of VWF for GP1bα
- Decreased high molecular weight (HMW) multimers
- Leads to increase clearance of vWF
- Increased RIPA
- No DDAVP
- Test: mutations in exon 28 of VWF gene
Type 3
- Autosomal recessive, most AD
- Severe marked deficiency
- Absence of vWF, F8 also low
- But may have nl coag parameters
- vW multimer test, all multimers low
- No DDAVP
vWF 2M and 2N
- Type 2M
- Defect in GP 1b binding, but no loss of HMW multimers
- vWF made but doesn’t work
- Decreased vWFRco
- +/- normal RIPA, vWF Ag, F8
- Suspect when vwf:RCo < vWF ag
- Type 2N (Normandy)
- Defective binding of vWF to F8
- Hemophilia-like (but AR), women w low F8, think of this dz
- Tests: decreased FVIII, decreased vWFAg:C levels
- Normal RIPA, multimers, ristocetin
- Normal sequence analysis of F8 gene to rule out hemophilia
- Frequency
- 2A>2N>2M>2B
24
Q
A
25
Q
vWD Type I
- multimers?
- frequency?
- tests?
- treated w DDAVP?
A
vWD Type I
- Low quantity, normal multimers, functionally normal
- Most common type
- Sometimes all tests are normal
- Only type treated w DDAVP
26
Q
vWD type 2a and 2b
- Type 2a
- multimers?
- tests?
- treated w DDAVP?
- Type 2b
- multimers?
- tests?
- treated w DDAVP?
- mutation?
A
vWD type 2a and 2b
- Type 2a
- Decreased large and medium sized multimers
- Disproportionately low vWF:RCo (quality) relative to vWFAg (quantity)
- Type 2b
- Mutation in exon 28 of VWF that causes increased affinity of VWF for GP1bα
- Decreased high molecular weight (HMW) multimers
- Leads to increase clearance of vWF
- Increased RIPA
- No DDAVP
- Test: mutations in exon 28 of VWF gene
27
Q
Type 3
- inheritance?
- multimers?
- tests?
- treated w DDAVP?
A
vWD Type 3
- Autosomal recessive, most AD
- Severe marked deficiency
- Absence of vWF, F8 also low
- But may have nl coag parameters
- vW multimer test, all multimers low
- No DDAVP
28
Q
vWF 2M and 2N
- Type 2M
- multimers?
- tests?
- treated w DDAVP?
- Type 2N (Normandy)
- genetics?
- multimers?
- tests?
- treated w DDAVP?
- Frequency
A
vWF 2M and 2N
- Type 2M
- Defect in GP 1b binding, but no loss of HMW multimers
- vWF made but doesn’t work
- Decreased vWFRco
- +/- normal RIPA, vWF Ag, F8
- Suspect when vwf:RCo
- Type 2N (Normandy)
- Defective binding of vWF to F8
- Hemophilia-like (but AR), women w low F8, think of this dz
- Tests: decreased FVIII, decreased vWFAg:C levels
- Normal RIPA, multimers, ristocetin
- Normal sequence analysis of F8 gene to rule out hemophilia
- Frequency
- 2A>2N>2M>2B
29
Q
Pseudo VWF—platelet type
- Mutations in __ resulting in ↑ binding of __to __ multimers
- The abnormality is on the patients __, not with __
- VW multimer test shows __ vWF multimers
- __RIPA studies
- Platelet agg studies show __
- Aggregation with __
- Mutations in __gene, whereas __ has mutations in exon 28 of VWF gene
A
Pseudo VWF—platelet type
- Mutations in GP1ba resulting in ↑ binding of GPIba to HMW VWF multimers
- The abnormality is on the patients platelets (GP1b), not with vWF
- Plts bind large VWF multimers
- VW multimer test shows decreased large vWF multimers
- Abn RIPA studies
- Platelet agg studies show low dose ristocetin aggregation
- Aggregation with cryoprecipitate
- Mutations in GP1bα gene, whereas VWF 2B has mutations in exon 28 of VWF gene
32
Q
Activated Protein C Resistance
- Fequency?
- Usually __ point mutation, which prevents inactivation by protein C, so __ production is unchecked, leading to thrombosis
- __ gene Mutation:
- Arg for gln at position 506 (__)
- Arg for threonine at position 306 (__)
- Mutation in __ and __
Dx
- Functional assay:___
- Screening test
- If pt doesn’t have APCR and you add ProtC to their specimen, ↑ PTT __
- If patient has APCR and you add ProtC to their specimen, ↑ PTT __
- PCR for __
A
Activated Protein C Resistance
- Most common cause of thrombophilia
- Usually Factor V point mutation, which prevents inactivation by protein C, so prothrombin production is unchecked, leading to thrombosis
- Factor V gene Mutation:
- Arg for gln at position 506 (Factor V Leiden)
- Arg for threonine at position 306 (Factor V Cambridge)
- Mutation in factor II and methylene tetrahydrafolate reductase (MTHFR)
Dx
- Functional assay: PTT:resistance ratio
- Screening test
- If pt doesn’t have APCR and you add ProtC to their specimen, ↑ PTT >2:1
- If patient has APCR and you add ProtC to their specimen, ↑ PTT <2:1
- PCR for Factor V Leiden mutations
33
Q
Protein C Deficiency
- __heterozygous, homozygous __
- Genetic cases have __risk of thrombosis
- acquired __
- __thromboembolism
- Coumadin -> __
- Laboratory diagnosis:
- Patient must be off __
A
Protein C Deficiency
- Usually heterozygous, homozygous die in infancy
- Genetic cases have increased risk of thrombosis
- acquired usually don’t
- Venous thromboembolism
- Coumadin -> skin necrosis
- Laboratory diagnosis:
- Patient must be off Coumadin
34
Q
Protein S Deficiency
- Prot S is a __to Prot C
- 40% is __
- 60% Protein S binds to ___
- __is an acute phase reactant
- increased __-> decreased Protein S
- Thus __ during stress (pregnancy)
- __is an acute phase reactant
- Labs:
- __ (worst test)
- __ (best test)
- Inheritance?
- Oral contraceptives, estrogen therapy and pregnancy
- decrease protein S, but not ___
A
Protein S Deficiency
- Prot S is a cofactor to Prot C
- 40% is free, functional protein S
- 60% Protein S binds to C4b binding protein
- C4b is an acute phase reactant
- increased C4b -> decreased Protein S
- Thus ↓ Prot S during stress (pregnancy)
- Labs:
- total protein S (worst test)
- protein S activity (best test)
- Autosomal dominant
- Oral contraceptives, estrogen therapy and pregnancy
- decrease protein S, but not protein C or antithrombin
35
Q
Antithrombin III deficiency
- Antithrombin binds to __to inhibit factors __
- In ATIII deficiency, patient presents w ↓response to __
- Acquired- __
- If a patient has thrombosis that you treat with __and the PT does not rise sufficiently, the patient may have ATIII deficiency
A
Antithrombin III deficiency
- Antithrombin binds to heparin to inhibit factors II and X.
- In ATIII deficiency, patient presents w ↓response to heparin
- Acquired- liver, nephrotic dz, DIC
- If a patient has thrombosis that you treat with heparin and the PT does not rise sufficiently, the patient may have ATIII deficiency
36
Q
Prothrombin G20210A Mutation
- __mutation leads to __prothrombin levels
- __is the location of the mutation in the gene
- Guanidine to adenine substitution in the 3’ untranslated portion of prothrombin gene on Chr _
A
Prothrombin G20210A Mutation
- Point mutation leads to high prothrombin levels
- 20210 is the location of the mutation in the gene
- Guanidine to adenine substitution in the 3’ untranslated portion of prothrombin gene on Chr 11
