C

2. Learning Outcomes
 By the end of the lecture, the learner is able to:
1. Review platelet plug, coagulation and dissolution
2. State certain conditions affecting the primary,
secondary and tertiary phases of coagulation
3. Describe PT and PTT

3. Review of physiology
 3 phases of hemostasis= platelet plug, coagulation and
fibrinolysis occur simultaneously

4. Platelet structure

5. Platelet plug
1. adhesion: Ia/IIa of plt and collagen; Ib/IX/V of
platelet and vWF and collagen
2. Adhesion activates platelets
3. Activation release granules: TXA2 activates more plts
4. Granules increase calcium which activates
phospholipase A2(PLA2)
5. Phospholipase modifies gpIIb/IIIa to increase
binding with fibrinogen

6. 6. Change in conformation
7. Cross linking of fibrinogen with gp IIb/IIIa
8. aggregation

7. Hemostatic plug formation.

9. Revised hypothesis of coagulation: two limbs of
the tissue factor pathway

10.  Diseases on platelet plug: vWD(poor adherence),
Bernard Soulier D(inability to bind vWF), storage pool
disease, release deficiency(aspirin), Glanzmann
thrombasthenia(def of gpIIb/IIIa)
 Fibrin clot: initiated by FVII+TF; intrinsic is only
amplification
 Fibrinolysis: plasmin

11.  Platelet agonists: ADP, thrombin, epinephrine,
collagen, TXA2
 Degranulation induced by calcium:
1. alpha: vWF, fibrinogen, Factor V, platelet specific
protein: PF4, beta-thromboglobulin
2. delta: serotonin, ATP, ADP, pyrophosphate, calcium

12.  Glycoproteins: gp
IIb/IIIa(absence =Glanzmann)
with fibrinogen
 Phospholipid expression upon
conformational change of
platelets: surface for FXa and
FVa which converts
prothrombin to thrombin;
monocytes and neutrophils

13.  Fibrin clot:
TF+FVII TF+FVIIa(TFPI)
1. FIX to FIXa
2. FX to FXa(amplified by FVa;
inhibited by ProCS)
prothrombin to thrombin;
FXIII to FXIIIa; fibrinogen to
fibrinclot

14.  Thrombin plays central role in
amplification:
1. FV to FVa(inhibited by ProCS)
2. FVIII to FVIIIa(inhibited by
ProCS)
3. FXI to FXIa
 FXII to FXIIa occurs in vitro
only(PTT); deficiency clinically
insignificant

15. Anticoagulant
System

16.  Natural anticoagulants: Tissue factor pathway
inhibitor, Protein C and S, antithrombin III
 Factor V Leiden mutation(Activated protein C
resistance)
 Vit K dependent factors: 10,9,2,7(1927)

17.  Protein C and S:
thrombin+thrombomodulin
activates ProC which binds
with free ProS inactivation
of FVa and FXa
 Antithrombin: with heparin
binds with thrombin; with low
molecular weight
heparininhibits FXa
 TFPI

18. Fibrinolysis: plasminogen(Tissue Plasminogen activator
and plasminogen activator inhibitors)
plasmin(antiplasmin) degrades to fibrin and fibrinogen to
fibrin split products( fragments X, Y, D and D-dimers)

20. Co-factors and
regulators
1. co-factors: calcium and
VitK
2. Regulators:
a. Protein C
b. antithrombin
c. TFPI
d. plasmin
e. Prostacyclin(PGI2)=
inc cytosolic cAMP
leading to inhibition
of degranulation

21. Tenase and prothrombinase
complex
 Tenase= FVIIIa and FIXa
to activate FX
 Prothrombinase= FVa
and FXa
 Targets of new
anticoagulants(existing
are VitK, antithrombin)

25. Common:
 aPTT
 PT(also INR)
 fibrinogen(Clauss method)
 platelet count
 platelet function testing(PFA-100)
Testing of Coagulation

26.  Contact activation pathway= aPTT
 Tissue factor pathway= PT; INR value to monitor
dosing of anticoagulants like warfarin
 Fibrinogen= thrombin clotting time; measurement of
exact amount by Clauss method; deficiency will affect
all screening tests
Common Coagulation Testing

27. Others:
 Thrombin clotting time, Bleeding time
 mixing assay, coagulation factor assay,
antiphospholipid antibodies, D-dimer
 Genetic tests(Leiden mutation, prothrombin G20210A)
 platelet function tests
 Thromboelastography(TEG or Sonoclot),
 euglobulin lysis time – measures how fast clots
breakdown (fibrinolytic activity in plasma)
Testing of Coagulation

28. Diseases
 Factor Deficiencies, Factor inhibitors
 Vit. K deficiencies
 DIC, Liver disease
 Platelet disorders
 Thrombotic disorders

29. • Congenital afibrinogenemia(absent;
homozygous) and
hypofibrinogenemia(reduced; heterozygous)
• Conditions are rare; umbilical stump bleeding
for homozygous; bleeding after surgery in
heterozygous
Fibrinogen Deficiencies

30. • Acquired hypofibrinogenemia:
-advanced liver disease
-DIC
-thrombolytic therapy
• Acquired Dysfibrinogenemia:
- abnormal fibrinogen in acute or chronic
liver disease
-primary or metastatic liver disease
Fibrinogen Deficiencies

31.  Prolonged: PT,PTT, TT
 Prolonged Reptilase time
 Venom of Bothrops snakes
 Has similar activity to thrombin
Typical lab tests for fibrinogen
deficiency

32.  Rare
 Two forms: reduced or absent production acquired or
congenital
 Acquired: FVII def, IX def, X def, Vit K def, warfarin
Tx, liver disease, lupus anticoagulant, topical bovine
thrombin
 PT,PTT prolonged, FII low
Prothrombin(Factor II) deficiency

33.  2 forms
 Acquired= liver disease and DIC
 Rarely combined Factor V and VIII def
 PT, PTT prolonged; low FV
Factor V deficiency

34.  2 forms
 Acquired= Vit K deficiency, warfarin Tx, deficiency
of FII, IX, X, DIC, liver disease
 PT prolonged
 PTT normal
 Low FVII also low FII,IX,X
Factor VII deficiency

35.  Factor 8 circulates in plasma bound to vWF
 90%= decreased levels of FVIII
 10%= abnormal molecule
 X linked recessive
 Characteristic: intra-articular, intracranial,
intramuscular hemorrhage
 PT normal, PTT prolonged
 Low FVIII; also low FII,IX,X
Hemophilia A(FVIII deficiency)

36. Stratification:
mild= 6-20% of normal activity; rare
bleeding
moderate= 1-5% of normal activity;
occasional spontaneous bleeding
severe= <1%; frequent spontaneous
bleeding
Hemophilia A

37.  IgG that binds to FVIII
 Reasons:
1. exogenous FVIII transfused
2. spontaneous inhibitors postpartum:
2-5 months after birth of 1st child;
disappears after 12-18 months
3. inhibitors with allergic and enhanced
immunologic reactions:
RA, SLE, malignancy, MM, PCN
4. no obvious underlying reasons
Factor 8 inhibitors

38.  PT normal
 PTT prolonged
 Mixing studies:
1. 1:1 normal at zero
incubation
2. at least 8 sec prolonged at 1:1 ratio incubated at
37C for 60-120 mins
 FVIII activity decreased
 FVIII inhibitor assay for quantification
Typical lab of Factor VIII inhibitor

39.  70-90%= decreased Factor 9
 10-30%= abnormal factor 9
 Same stratification with Hemophilia A
 1-5% have inhibitor
Hemophilia B(Factor IX def)

40.  Rare
 Acquired or congenital
 Amyloidosis= amyloid material irreversibly binds
with Factor X
 Lab: PT, PTT prolonged
 Low FX
Factor X deficiency

41.  Common
 Homozygotes have 20% activity
 Heterozygotes have 20-70% activity
 Jewish descent; Ashkenazi origin
 Bleeding does not correlate well with FXI activity
 Acquired= pregnancy, proteinuria, DIC
 Lab: PT normal, PTT prolonged, low FXI
Factor XI deficiency

42.  FXII, PK, HMWK
 Prolongs PTT
 No clinical bleeding
 PT normal
Deficiency of contact factors

43.  Rare
 Umbilical cord stump
bleeding in homozygotes
 PT, PTT normal
Factor XIII deficiency

44.  Occasional bleeding
 Acquired= liver disease,
nephrotic syndrome, amyloidosis,
DIC, thrombolytic therapy
 Typical Lab:
PT normal
PTT normal
antiplasmin decreased
Antiplasmin deficiency

45. Diseases
 Factor Deficiencies, Factor inhibitors
 Vit. K deficiencies
 DIC, Liver disease
 Platelet disorders
 Thrombotic disorders

46.  Reasons:
warfarin, antibiotics, malabsorption
syndrome, decreased Vit K intake,
long term parenteral nutrition, biliary
obstruction
 PT prolonged; prolongation does not predict
risk of hemorrhage
Vit K deficiency

47.  PT prolonged
 PTT maybe prolonged
 FII,FVII, FIX, FX, protein C and S
deficiencies
 Always rule out warfarin
Typical lab of Vit K deficiency

48. Diseases
 Factor Deficiencies, Factor inhibitors
 Vit. K deficiencies
 DIC, Liver disease
 Platelet disorders
 Thrombotic disorders

49.  Causes: 10-20% gram negative sepsis
- OB complication
- extensive tissue injury
- liver disease
- ABO incompatible blood
transfusion
ARDS
chronic= malignancy:
Promyelocytic
Leukemia, solid tumors
DIC

50.  microvascular thrombosis
 consumption of platelets and
coagulation factors
 followed by hemorrhage and
overactivation of the fibrinolytic
system
Signs and Symptoms of DIC

51.  Increased FDP or D dimer
 Prolonged PT
 Prolonged PTT
 Decreased platelets
 Decreased fibrinogen
 Positive schistocytes in
peripheral smear
Typical lab tests of
DIC

52.  D dimer or FDP positive due to decreased
clearance by the diseased liver
 Fibrinogen decreased or normal
 Platelets decreased or normal
 Coagulation factors may have deficiencies
Liver disease may have DIC
or DIC like syndrome

53. Diseases
 Factor Deficiencies, Factor inhibitors
 Vit. K deficiencies
 DIC, Liver disease
 Platelet disorders
 Thrombotic disorders

54.  Accelerated platelet destruction in the
absence of DIC, TTP, drug induced and
neonatal thrombocytopenia
 Antibody mediated
 May be associated with Helicobacter
pylori
Idiopathic immune
thrombocytopenic purpura(ITP)

55.  Acute=antipathogen Ab cross reacting
with an epitope on platelet membrane
 Chronic=platelet autoAb to platelet
glycoproteins
Idiopathic immune
thrombocytopenic
purpura(ITP)

56.  acute= <20,000/cumm platelets(20x109/L)
 Chronic=>50,000 /cumm platelets
 Platelets are large on peripheral smear; megakaryotes
are increased in the BM
 PT, PTT normal
Typical lab test results of ITP

57.  Hx: heparin, quinidine, quinine, gold salts,
sulfonamides.
: include soft drinks, topical meds, over the
counter drugs which may contain quinine
 IgG +drug binds to plt destruction
 Heparin induced thrombocytopenia(HIT) - PF4 is the
antigen
Drug induced thrombocytopenia

58.  Decreased in platelets 7-10 days after blood
transfusion
 Ab mediated destruction of transfused and
autologous platelets
 Ab to HPA-1a which patients lacks
Post transfusion purpura

59.  Transplacental maternal IgGcoats HPA-1a fetal
platelets removed by the RES newborn
hemorrhagic diathesis
 50% mortality due to intracranial hemorrhage
 Thrombocytopenia persists for 2 wks
Neonatal alloimmune
thrombocytopenia(NAIT)

60.  Clonal proliferation of neoplastic multipotent stem
cell
 Hemorrhages and thrombosis
 Increased platelet count and BM megakaryocytic
hyperplasia
 Spent phase= myelofibrosis and decreased platelet
counts
Essential thrombocythemia

61.  Functions of vWF: plt adhesion, binding of FVIII
prolonging half life
 Types: quantitative, qualitative
 >60% of patients have blood type O
von Willebrand disease

62.  Ristocetin co-factor activity functional assay=
abnormal or no aggregation
 vWF assay for quantity
 FVIII coagulant activity= decreased secondary
to low vWF
 vWF multimeric analysis for size distribution
Typical lab of vWD

63.  BS= decreased functional gpIb/IX/V, the plt
receptor for vWF
 GT= decreased functional gpIIb/IIIa, the
complex that binds fibrinogen to plts
Bernard Soulier; Glanzmann
thrombasthenia

64.  Congenital
 Acquired= cardiopulmonary by pass
Acute leukemias
Myeloproliferative
disorder
Storage Pool Disease

65.  Uremia= platelet dysfunction
endothelial cell dysfunction
 Drug induced= Aspirin
Clopidogrel(Plavix)
Uremia and Drug induced
thrombocytopenia

66. Diseases
 Factor Deficiencies, Factor inhibitors
 Vit. K deficiencies
 DIC, Liver disease
 Platelet disorders
 Thrombotic disorders

67.  Hypercoagulable states
 Hereditary or acquired
1. Activated Protein C Resistance
= mutation of FV(Leiden)
prevents protein C mediated
inactivation of FV
2. Prothrombin G20210A=mutation in the
promoter of the prothrombin
geneincreased synthesis of
prothrombin
Thrombotic Disorders

68. 3. Hyperhomocysteinemia= increased
thrombosis
4. Antiphospholipid antibodies= Lupus
anticoagulant, anticardiolipin, and
B2glycoprotein I Ab
Thrombotic Disorders
B2 glycoprotein binds to platelet plasma
membrane, leading to platelet activation)

69.  Antiphospholipid Abs= IgG, IgM, IgA
Lupus anticoagulant= Ig that interferes with
phospholipid dependent coagulation reactions
without inhibiting activity of any specific
coagulation factors
= targets phospholipids bound to
prothrombin, B2 glycoprotein 1, protein C
and protein S
Acquired Hypercoagulable States

70. anticardiolipin Ab= targets B2 glycoprotein1 bound to
a phospholipid, cardiolipin
anti beta2 glycoprotein 1 Ab= targets beta2
glycoprotein 1 in the absence/ presence of
phospholipid
(B2 glycoprotein binds to platelet plasma membrane,
leading to platelet activation)
Acquired Hypercoagulable States

71.  SLE, malignancy, drugs(procainamide,
quinidine), bacterial(SY and TB), viral, fungal,
protozoal and vaccinations
 Lupus Anticoagulant= anticoagulant in vitro
only; false positive VDRL
 APAS= venous and arterial thrombosis;
recurrent abortions; Ab’s vs. protein-
phospholipid complexes (PL)
Conditions associated with
antiphospholipid Abs

72.  L.A.= prolonged aPTT
Mixing studies not normalized;
use DRVVT(reduced
phospholipid)
 ELISA IgG IgM for anti-cardiolipin and
anti -B2 glycoprotein 1
Typical lab tests for APAS

73.  Pathology= fibrin hyaline thrombi in small
arteries, arterioles, capillaries
 Deficiency of vWF cleaving protease
 Non specific manifestations:
Cardiac
Pulmonary
GIT
Lab: schistocytes, decreased platelets,
normal PT and fibrinogen
Thrombotic thrombocytopenic
purpura(TTP)

74.  Triad or pentad:
1. Decreased platelets with purpura, mucous
membrane bleeding
2. Microangiopathic hemolytic anemia
3. Neurologic abnormalities
4. Fever
5. Renal dysfunction
Thrombotic thrombocytopenic
purpura(TTP)

75.  Fever, microangiopathic hemolytic anemia,
decreased platelets, renal dysfunction
 Hyaline thrombi in glomerulus
 Non-familial= Shiga toxin E. coli
 Familial= abnormal in complement factors H
and I
 Pediatric patients with history of diarrhea
Hemolytic uremic syndrome

76. Thank you