Case Studies in Clinical Hemostasis Case Studies in ... - Pathology

Case Studies 

in 

Clinical 

Hemostasis




Hemostasis 

Case #1 

Patient J.M.

Patient J.M. 

! Middle-aged man admitted for elective 

cholecystomy 

! Two previous dental extractions associated 

with rebleeding requiring repacking 

! History of easy bruising and occasional 

nosebleeds 

! No other operative procedures 

! No history of trauma 

! Family history negative for bleeding and 

thrombosis 

! Physical examination unremarkable except for 

abdominal tenderness

Patient J.M. 

600 

20 

50 

20 

THOU/uL 

500 

400 

300 

200 

100 

● 

Seconds 

15 

10 

5 

● 

Seconds 

45 

40 

35 

30 

25 

● 

Minutes 

15 

10 

5 

● 

0 

PLTS 

0 

PT 

20 

APTT 

0 

Bleeding Time

Primary & Secondary Hemostasis 

Primary Hemostasis 

Platelet Adhesion & Aggregation 

Platelet Plug Formation 

Secondary Hemostasis 

Coagulation 

Platelet Plug Stabilization

Platelet Structure 

Surface canalicular system 

Surface receptors 

Mitochondria 

Lysozymes 

α-granules 

Microtubules 

Dense bodies 

Cell membrane 

Glycogen granules

Damaged Damaged Vessel Vessel Wall Wall 

Platelet 

Function 

Platelet Platelet Adhesion Adhesion 

Platelet Platelet Shape Shape Change Change 

Primary Primary Aggregation 

Aggregation 

Metabolic Metabolic Events Events 

Degranulation 

Secondary Secondary Aggregation 

Aggregation

Platelet Activation 

ADP 

Resting 

platelet 

Activated platelet 

with FbR 

Doublet and 

multiplet formation

GPIb 

GPIIbIIIa 

PLT 

Function 

Platelet membrane 

Adhesion site 

Aggregation, vWF, and 

fibrinogen binding site 

vWF 

VIII:C 

Subendothelial 

collagen

Sources of vWF 

Platelets 

Endothelial Cell 

Weibel-Palade 

Body (HMW) 

α-Granule (LMW)

Platelet 

Agonists 

Membrane 

Glycoprotein 

Membrane 

Phospholipids 

Phospholipase 

Arachidonic Acid 

Platelet 

Metabolism 

Dense 

Granules 

Cyclo-oxygenase 

Cyclic 

Endoperoxidases 

ADP 

Thromboxane 

Synthetase 

Platelet 

Aggregation 

TxA 2 

TxA 2

Platelet Aggregation Studies 

Platelet agonist* 

Incubate 10 minutes 

Measure light transmission 

Platelet rich plasma 

Aggregated platelets 

* Platelet agonists - ADP, epinephrine, collagen 

ristocetin, arachidonic acid, thrombin

Platelet Aggregation 

Light 

Shape 

Change 

Secondary 

Aggregation 

Primary 

Aggregation 

Time

100 

80 

60 

ADP 

Normal Aggregation 

100 

80 

60 

EPI 

40 

ADP - 1 µM 

40 

20 

ADP - 1 µM 

ADP - 1 µM 

20 

EPI 5 µM 

0 

100 

80 

60 

40 

20 

0 

0 2 4 6 8 10 

Time (Minutes) 

COLL 

Collagen 2 µg/mL 

0 2 4 6 8 10 


0 

100 

80 

60 

40 

20 

0 

0 2 4 6 8 10 


RIST 

Ristocetin 1.2 mg/mL 

0 2 4 6 8 10 

Time (Minutes)

Coagulation 

Prothrombin 

Thrombin 

Fibrinogen 

Fibrin

Coagulation 


Tissue 

Factor 

Extrinsic 

Pathway 

Va 

VIIIa 

Xa 

Va 

VIIIa 

Xa 

Intrinsic 

Pathway 

Factor 

XII 




Contact 

Factors 

- Charged 

Surface 

Modern Concept 

of Coagulation 

XI XI 

XIa XIa 

VII 

IX IX 

IXa IXa 

Tissue 

Factor 

Injured 

Tissue 

VIII 

VII 

XX 

Xa Xa 

V 


Thrombin

Coagulation 


Tissue 

Factor 


Time 


Pathway 

Va 

VIIIa 

Xa 

Va 

VIIIa 

Xa 


Pathway 

Factor 

XII 





Time (PT) 

Thromboplastin 

Ca ++ 

Plateletrich 

plasma 

Incubate 

Fibrin 

clot

Coagulation 


Tissue 

Factor 


Pathway 

Va 

VIIIa 

Xa 

Va 

VIIIa 

Xa 



Pathway 

Factor 

XII 

Activated Partial 

Thromboplastic 

Time (aPTT) 



Activated Partial 


Time (aPTT) 

Partial 


Platelet Activator 

Ca ++ 

Plateletrich 

plasma 

Incubate 

Fibrin 

clot

Patient J.M. 

! Middle-aged man admitted for elective 

cholecystomy 

! Two previous dental extractions associated 

with rebleeding requiring repacking 

! History of easy bruising and occasional 

nosebleeds 

! No other operative procedures 

! No history of trauma 

! Family history negative for bleeding and 

thrombosis 

! Physical examination unremarkable except for 

abdominal tenderness

Defects of Hemostasis 

Bleeding 

Thrombosis

Vascular Defects 

! Hereditary vascular purpuras 

Hereditary connective tissue diseases 

Hereditary vascular malformations 

! Acquired vascular purpuras 

Age-related vascular purpura 

Mechanical purpuras 

Vitamin C deficiency (Scurvy) 

Vasculitis/infection 

Henoch-Schonlein purpura 

Miscellaneous diseases

Platelet Diseases 


Thrombosis 

Platelet production 

Shortened survival 

Defective adhesion 

Defective aggregation 

Defective activation 

Antiplatelet antibodies 

Hyperactive 

platelets 

Excess activation

Diseases of Coagulation 

! Inherited diseases 

von Willebrand’s disease 

Factor deficiencies 

! Acquired 

diseases 

Disseminated intravascular coagulation 

Caogulation inhibitors 

Vitamin K deficiency 

Drug-induced hemorrhage 

Dysproteinemias 

Bleeding after cardiopulmonary bypass

Factor Activity (%) 

200 

180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

Factor I 

Factor II 

Factor V 

Factor VII 

Factor VIII 

Factor IX 

Factor X 

Factor XI 

Factor XII 

vWF:RCoF 

vWF:Ag 

Patient J.M. 

● 

● ● 

● 

● 

● 

● 

Prekallikrein 

● 

HMWK 

●

GPIb 

GPIIbIIIa 

PLT 

Function 


Adhesion site 



vWF 

VIII:C 

Subendothelial collagen

GPIb 

GPIIbIIIa 

vWD 


Adhesion site 



vWF 

VIII:C 

Subendothelial 

collagen

Worldwide 

Prevalence of 

vWD is 1-3%

History of vWD 

! 1926 - Erik Adolf von Willebrand 

described family with bleeding disorder 

! Swedish island of Foglo in Aland 

archipelago 

! Termed “hereditary pseudohemophilia” 

! 1953 - Deficiency of plasma protein 

distinct from factor VIII 

! Multiple clinical variants discovered 

! Most common congenital hemostatic 

disorder

von Willebrand’s Disease 

Clinical Features 

! Common hereditary procoagulant disease 

! Frequently mild, most cases undiagnosed 

! Multiple clinical variants 

! Easy brusising very common 

! Mucosal bleeding (epistaxis, GI bleeding, 

menorrhagia) very common 

! Prolonged bleeding after surgery or trauma 

a 

! Bleeding caused by drugs affecting platelet 

function 

! No history of hemarthroses or intramuscular 

hematomas


Features 

of vWD 

Epistaxis 

Easy Bruising 

Drug-Induced 


Prolonged 

bleeding after 

trauma 

Menorrhagia 

GI Bleeding

Relationship Between vWF 

and ABO Blood Groups 

Individuals with 

Blood Group O have 

significantly lower 

levels of vWF than 

those with blood 

groups A, B, or AB


Classification 

! Type 1 - 70-80%, mild, autosomal recessive 

! Type 2 

Type 2A - 15-20%, mild 

Type 2N - Rare, moderate, failure of vWF to 

complex with VIII:C 

Type 2B - Rare, thrombocytopenia, 

increased vWF affinity for PLTS 

! Type 3 - Very rare, severe, decreased vWF and 

factor VIII, autosomal recessive 

! Platelet-Type Pseudo vWF - Abnormality of PLT 

GP1b receptor, increased vWF affinity, 

resembles Type 2B 

! Acquired vWF - Usually autoimmune etiology


Laboratory Features 

! Normal PLT (with exceptions) 

! Prolonged bleeding time 

! Prolonged aPTT 

! Decreased factor VIII activity 

(FVIII:C) 

! Decreased vWF antigen 

(vWF:Ag) 

! Abnormal ristocetin cofactor 

activity (vWF:RCoF) 

! Abnormal vWF multimeric 

composition 

! Molecular 

abnormalities

Diagnostic Assays for vWD I 

! Factor VIII activity 

Clotting assay 

Capacity of patient plasma dilutions to correct 

clotting time of FVIII-deficient plasma 

! vWF Activity (RCoF Activity) 

Platelet aggregation assa y 

Different concentrations of ristocetin mixed with 

patient PPP and normal platelets 

! vWF Antigen 

Immunoassay quantitation 

ELISA commonly utiized

Diagnostic Assays for vWD II 

! Ristocetin-induced agglutination assay 

Platelet aggregation assay 

Patient PRP + graded ristocetin concentrations 

! Cryoprecipitate-induced agglutination assay 

Patient PRP + normal cryoprecipitate 

Spontaneous agglutination with platelet-type 

pseudo-vWD 

! vWF multimer analysis 

Gel 

electrophoresis 

Subtypes show different migration patterns 

Used to subtype vWD after Dx established 

Laborious and expensive

vWF Multimers 

Large 

Multimers 

Intermediate 

Multimers 

Small 

Multimers 

Normal 

Type I 

Type IIA 

Type IIB 

Type III

vWF Treatment 

! Replacement therapy 

Plasma derived factor VIII concentrates 

Type 3, type 2B, type 2N 

Factor VIII concentrates, cryoprecipitate 

Platelets 

Platelet-type 

pseudo-vWD 

Plasma concentrates contraindicated 

! Desmopressin 

acetate 

Synthetic analog of vasopressin 

Stimulates vWF and factor VIII release 

Mainstay of Rx for Type I and Type 2A 

Injection and nasal spray 

! Ancillary therapy 

Fibrinolytic inhibitors and “fibrin glue”




Hemostasis 

Case #1 

The End

Case Studies in Clinical Hemostasis Case Studies in ... - Pathology

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