1. Bleeding DISORDERS Maher A. Sughayer MD, FCAP Chair, Pathology Dept.
King Hussein Cancer Center

2. Hemostasis Hemostasis depends on the integrity of Blood vessels
Platelets
Coagulation factors
Anticoagulation factors

3. Initial Laboratory Tests For Bleeding Abnormalities
Platelet count.
Bleeding time.
Partial thromboplastin time (PTT).
Prothrombin time (PT).
Thrombin time(TT).

4. Causes of Abnormal Bleeding
Vascular disorders.
Platelet causes: (Thrombocytopenia, functional defects).
Defective coagulation.

6. Vascular Bleeding Disorders
Easy bruisability and bleeding from small vessels.
Caused by abnormal vessels or abnormal perivascular connective tissue.
Sites of bleeding: skin and mucous membranes.
Bleeding time and other screening tests are normal.
Congenital or acquired.

7. Acquired Vascular Defects
Senile purpura due to atrophy of perivascular connective tissue.
Scurvy.
Steroid purpura (defective CT).
Hereditary hemorrhagic telangiectasia
Ehlers-Danlos syndrome.
Vasculitis:
-Hypersensitivity:
Henoch-Schoenlein purpura
- Septic: infections.
measles
dengue
meningococcemia
ricketsial infections

8. Platelet causes Thrombocytopenia (quantitative)
Platelet function disorders (qualitative)

9. Relationship Between Platelet Count and Bleeding
Normal range X103 per µl.
Levels above 60x103/µl will not cause bleeding under normal conditions.
Levels below 20x103/µl will cause:
Petechiae, mucosal bleeding.
Post-operative bleeding, CNS bleeding.
Levels around 5x103/µl can lead to fatal CNS or GI hemorrhage.
Levels between 20 and 60x103/µl may cause bleeding (depending on platelets functional status).

10. Classification of Thrombocytopenia
Failure of production
Increased platelet destruction
Sequestration: hypersplenism
Dilutional

11. Thrombocytopenia Due to Failure of Production
Decreased BM megakaryocytes
Infiltrative diseases of BM
Aplastic BM
Amegakaryocytic thrombocytopenia
HIV infection
Drugs
Increased BM megakaryocytes
Megaloblastic anemia
Myelodysplasia
Alcohol induced
Rare diseases such as Wiskott-Aldrich syndrome

12. Thrombocytopenia Due to Increased Platelets Destruction
ITP
Secondary immune thrombocytopenia as in SLE
Drug related immune thrombocytopenia as in quinidine and heparin.
Post transfusion thrombocytopenia
Neonatal thrombocytopenia either due to autoantibodies or alloantibodies
DIC and microangiopathic hemolytic anemia

13. Chronic Immune Thrombocytopenic Purpura (ITP)
High incidence in women of child bearing age.
Mostly idiopathic, secondary causes include SLE, HIV, CLL, Hodgkin’s disease.
Autoantibodies against GP IIb/IIIa, or Ib/IX.
Platelets lifespan reduced to hours.
Megakaryocytes increased.
Petechial bleeding, easy bruising, menorrhagia.

14. ITP Diagnosis Decreased platelet count (10-50x109/l).
Hb. and WBCs are normal.
Increased megakaryocytes numbers in BM.
Antiplatelet antibodies.
? Antinuclear antibodies in SLE.
? Coomb’s test in Evan’s syndrome.

15. ITP Treatment Steroids. Splenectomy. High dose IV immunoglobulins.
Immunosuppressive therapy.
Platelets transfusion: Not helpful

16. Acute ITP Affects children.
Preceded by infection or vaccination in 75% of cases.
Spontaneous remission in >90% of cases.
Severe cases benefit from steroids or IV immunoglobulins.

17. Thrombotic Microangiopathies
Widespread formation of thrombi in the microcirculation composed of platelets and fibrin.
Consumptive thrombocytopenia and microangiopathic hemolytic anemia
TTP: 5 criteria
HUS; usually no CNS caused by endothelial injury secondary to E.coli O157:H7 infection in children, elderly

18. TTP
Deficiency of metalloprotease (ADAMTS13) needed for cleaving very hmw vWF (usually acquired autoAb, but may be inherited)
Accumulation of vhmw vWF leading to thombi
Thrombocytopenia, fever, CNS, renal microangiopathic hemolytic anemia.
Normal PT, PTT
Plasma exchange.

19. Platelet Membrane Glycoproteins
GP Ia-IIa: adhesion to collagen.
GP Ic-IIa: laminin receptor.
GP IIb-IIIa: binding to fibrinogen.
GP Ib-IX: adhesion to subendothelial tissue via vWF.

21. Qualitative Platelet Disorders

22. Qualitative disorders of platelets (1)
Bernard Soulier syndrome
Adhesion Defect
Autosomal recessive.
Deficiency of GpIb/IX (CD42) which serves as the receptor for vWF.
Giant platelets.

23. Giant Platelets

24. Qualitative disorders of platelets 2
Glanzman’s thrombasthenia
Aggregation defect
Failure to aggregate in response to ADP, collagen, epinephrine and thrombin
Autosomal recessive
Deficiency of GpIIb/IIIa (CD41/CD61) which serves as the receptor for fibrinogen.
Storage pool diseases
Initial aggregation normal, but secretion of thromboxane, ADP, and other granules contents impaired

25. Coagulation disorders
Congenital or acquired
Acquired: are the most common
many factors simultaneously deficient
-- Vit. K deficiency: II, VII, IX, X
-- Liver disease (most factors synthesized
in the liver)

26. von Willebrand Factor (vWF)
Coded by a gene located on the short arm of chromosome 12
The primary ptn. product is a 250,000 Da dimer.
Transformed by multiple disulfide bonds to form a series of multimers ranging in weight from 10,000,000 to 20,000,000 Da

28. vWF Adhesive protein, bridges collagen to platelets receptor GPIb
Carrier protein to factor VIII
Ristocetin induces platelets agglutination in the presence of vWF
Stored in Weibel-Palade bodies of endothelial cells, and a granules of platelets

29. von Willebrand Disease
The most common hereditary bleeding disorder (prevalence 0.1-1%).
Mild bleeding problems
Mucous membrane bleeding
Easy bruising
menorrhagia
Post-operative bleeding
Most cases are inherited as autosomal dominant disorder.
Prolonged bleeding time

30. von Willebrand Disease type I
The most common type (75% VWD cases).
Autosomal dominant disorder with variable penetrance (60%)
Reduced circulating vWF and factor VIII.
All sizes of vWF multimers are present
Slight prolongation of APTT
Platelets fail to agglutinate by ristocetin

31. von Willebrand Disease type II
Reduced circulating large and intermediate multimers of vWF.
vWF hmw is missing in type A
vWF has hightened interaction with GP1b in type B
Fctor VIII level is normal.
Failure of agglutination by ristocetin in IIa.
smaller ristocetin doses cause aggregation of platelets in type IIb.
Platelet type VWD is similar to type IIb, but GPIb is defective. Cryo precipitate alone can induce agglutination of platelets

32. von Willebrand Disease type III
Absent plasma vWF
Markedly reduced factor VIII coagulant activity
Autosomal recessive inheritance

33. von Willebrand Disease type IIN
Formerly known as VWD Normandy
Mutation in vWF affecting association with factor VIII
Manifestations similar to hemophilia, but transmission is autosomal recessive
Should be suspected in hemophilia patients if:
Inheritance is not sex-linked
Poor response to factor VIII infusion

34. von Willebrand Disease
Manegement
DDAVP which releases vWF from endothelial cells.
Single donor plasma concentrate.
Factor VIII concentrate or cryoprecepitate for type III von Willebrand disease

35. Inherited Deficiencies of Coagulation Factors
Deficiency
Fibrinogen
Prothrombin
Factor V
Factor VII
Factor VIII
Factor IX
Factor X
Factor XI
Factor XIII
Incidence in
Population
1:1 million
1:2 million
1:500,000
1:10,000
1:60,000
Gene on
Chromosome 4 11 1 13 X
6 & 1
Mode of
Inheritance AR
XLR

36. Hemophilia A Incidence: one in 10,000.
Sex-linked. 1/3 of the cases have no family history (recent mutation or generations of silent carriers).
Caused by absolute reduction of factor VIII or normal amount but defective factor VIII.
Severity of disease depends on factor VIII level
Normal level U/dl
Severe cases level <2 U/dl
Moderate cases level 2-5 U/dl
Mild cases level U/dl

37. Hemophilia A Sites of bleeding: Laboratory tests:
Large joints and soft tissue
Urinary tract and GI tract
Brain
Nose
Laboratory tests:
Prolonged PTT. Normal PT and TT.
Low factor VIII assay.
Treatment: replacement therapy (factor VIII concentrate or recombinant VIII).
Inhibitor antibodies develop in 18-50% of patients

39. Nomenclature of Factor VIII
Factor VIIIc
Factor VIIIAg
Protein lacking or aberrant in hemophilia A
Functional property of factor VIII missing in hemophilia A, measured by coagulation assays
Antigenic property of factor VIII, measured by immunoassays

40. Factor VIII (FVIII) and the FVIII Gene
The gene is located at the tip of the X chromosome.
Huge gene composed of 26 exons.
FVIII mRNA is ~9kb, and encodes a 300kD protein.
FVIII is acofactor for F IX in the proteolytic activation of F X.
Bound to vWF in plasma.
Markedly unstable in the absence of vWF.

41. Molecular Genetics of Hemophilia A
Point mutation in exons or splice junctions (~50%)
Inversion of intron 22 (~45%)
Deletions or less commonly insertions (~5%)

42. Hemophilia in Females Exceedingly rare, seen in:
Mating between a carrier mother and affected father
Carriers with abnormalities of X-chromosome
Extreme lyonization
X mosaicism or deletion
Newly mutant gene

43. Hemophilia B Bleeding sites: similar to hemophilia A.
Incidence: one in 60,000.
Sex-linked.
Severity of disease depends on factor IX level
Normal level U/dl
Severe cases level <2 U/dl
Moderate cases level 2-5 U/dl
Mild cases level U/dl
Bleeding sites: similar to hemophilia A.
Laboratory tests:
Prolonged PTT. Normal PT and TT.
normal factor VIII assay.

44. Disseminated Intravascular Coagulation (DIC)
Widespread thrombi in the microcirculation with secondary consumption of platelets and coagulation factors (consumptive coagulopathy)
acute, subacute and chronic
Relase of tissue factor or endothelial damage: activation of extrinsic coag. cascade and dec. inhibitory pathways

45. DIC

46. DIC (Consumptive Coagulopathy)
Thrombosis, fibrinolysis, bleeding.
Obstetric complications; infections; cancers (panc, lung, prost, stomach, APML), massive tissue injury (trauma, burn), others (shock, liver, heat stroke, vasculitis, intravascular hemolysis).
Lab: Low plat and fibrinogen, high PT. PTT and FDP

47. DIC Microangiopathic hemolytic anemia, infarcts, hemorrhages
microthrombi and infarcts in most organs esp. kidneys, brain, adrenals, heart
Small infarcts in kidneys, but in severe cases cortical necrosis
Adrenal, pituitary, placenta
Clinical: bleeding in acute, thrombosis in chronic; minimal, or severe shock, coma