CHAPTER 1 - HEMOSTASIS PART 5 Flashcards
BLEEDING DISORDERS
- Superficial bleeding
- Deep tissue bleeding
Superficial bleeding -Ex:
epistaxis, petechiae, gingival bleeding
associated with platelet disorder or defect (either in function or in morphology) and with a vascular disorder
Superficial bleeding
caused by a defect in primary hemostasis
Superficial bleeding
Deep tissue bleeding -Ex.
hemarthrosis, hematomas
caused by a defect in secondary hemostasis (clotting or coagulation factors)
Deep tissue bleeding
QUALITATIVE PLÄTELET DISORDERS Manifested by
excessive bruising, superficial bleeding and prolonged BT.
External factors: acquired from a viral infection from an inflammation caused by lifestyle or others
- Acquired
Mild
- Acquired
Hereditary or inborn errors
- Congenital
characterized by 3 major platelet function (adhesion, aggregation, platelet/granule release)
- Congenital
- problem or defect with the interaction of platelet and blood vessel
Adhesion Defects (Platelet-vessel wall interaction)
BernardSoulier Syndrome
• Deficiency in
Gp Ib/IX complex
- complex responsible for adhesion
Gp Ib/IX and von Willebrand complex
BernardSoulier Syndrome
• Characterics:
large platelets and thrombocytopenia
BernardSoulier Syndrome
• Laboratory:
Prolonged Bleeding Time
No platelet count formed because the platelet cannot adhere to the bv/skin
BernardSoulier Syndrome
• Aggregation studies
a. Normal with:
b. Abnormal with:
Epinephrine, ADP, Collagen
Ristocetin
(in-vitro; collection of blood sample and induce aggregation using the ff. chemicals that are also found in the body that stimulates platelet aggregation and adhesion):
• Aggregation studies
BernardSoulier Syndrome
Treatment: cannot be corrected by adding [?]; no specific treatment; [?]–
normal plasma or cryoprecipitate
Desmosin acetate + recombinant factor Vila
used to arrest the bleeding if needed
Desmosin acetate + recombinant factor Vila
generate clot using tissue factors
Desmosin acetate + recombinant factor Vila
temporary treatment
Desmosin acetate + recombinant factor Vila
Transfusion of normal plasma will still continue bleeding; Platelet transfused will be worn out; Original plt will still have the defect of adhesion
BernardSoulier Syndrome
manifested in infancy or childhood
BernardSoulier Syndrome
BernardSoulier Syndrome signs and symtoms:
1) epistaxis, 2) gingival bleeding, and 3) ecchymosis
4 glycoproteins required to form Gp Ib/IX complex:
o Gp Iba – Chromosome 17
o Gp IbB – Chromosome 22
o Gp IbIX – Chromosome 3
o Gp V – Chromosome 3
: attaches thrombin and VWF to the injury site
o Gp Iba – Chromosome 17
: major complex for adhesion but enhanced with Gp V
Gp Ib/IX
enhances the fx of these receptors to complete the adhesion complex (Gp Ib/IX and von Willebrand complex)
Gp V
: complex is present, but nonfunctional/defective
Pseudo Bernard-Soulier Syndrome
von Willebrand disease
• (Autosomal) deficiency in
plasma VIII:vWF (Factor VIII complex)
cannot exist alone like VIII
vWF
– in complex with a multimerprotein, w/c is vWF
Factor VIII complex
• Same aggregation test result with Bernard-Soulier
von Willebrand disease
von Willebrand disease
• Common sign/Characterics:
mucocutaneous bleeding
von Willebrand disease
• Laboratory:
Platelet count and morphology are generally NORMAL
von Willebrand disease
• Aggregation studies:
a. Normal with:
b. Abnormal with:
Epinephrine, ADP, Collagen
Ristocetin
von Willebrand disease
• Diagnosis:
Standard WWD test panel tests:
1. quantitative VWF test (VWF: Ag assay)
2. VWF activity test/ VWF:RCo assay (qualitative; ability of WWF to bind to platelets)
3. factor VIll activity assay
von Willebrand disease
• Treatment:
Cryoprecipitate; Desmopressin acetate (1-desamino-8-D arginine vasopressin/ DDAVP)
Cryoprecipitate contains:
F I (fibrinogen), F VIII, F XIII, VWF, Fibronectin
: adhesive ligand (causes the production of clot
V Fibronectin
promotes spreading of plt and adhesion of wbc to avoid infection
Fibronectin
: causes the release of VWF antigen in the linings of bv
Desmopressin acetate
: carries F VIII complex
VWF antigen
Partial quantitative deficiency of von Willebrand factor (VWF); approximately 75%
1
Qualitative deficiency of VWF
2
weight multimers (the WWF is more susceptible to proteolysis by ADAMTS-13)
2A
Increased affinity for platelet glycoprotein Ib/IXN
2B
Decreased platelet receptor binding
2M
(Normandy Variant) Impaired factor VIII binding site
2N
WWF is absent or nearly absent from plasma
3
Glanzmann’s Thrombasthenia
Deficiency in
Gp IIb-IIIa
(receptor for aggregation)
Gp IIb-IIIa
Glanzmann’s Thrombasthenia
• Characterics:
Platelet tends to remain isolated
Defect in the hemostati/platelet plug
Glanzmann’s Thrombasthenia
Glanzmann’s Thrombasthenia
• Laboratory:
a. Normal plt ct and morphology
b. Abnormal in vitro clot reaction
c. Thrombosthenia
compact plt clot will be reduced and mediated by actomyosin or thrombostenin of the activated plts (helps the clot to undergo fibrinolysis)
Glanzmann’s Thrombasthenia
week plts cannot contract; clot retraction is abnormal
c. Thrombosthenia
Glanzmann’s Thrombasthenia
• Aggregation studies:
a. Abnormal with:
b. Normal with:
Epinephrine, ADP, Collagen
Ristocetin
- is a strong CF to cause plt release even if not aggregated
Thrombin
allows plt release during adhesion even w/o aggregation to still help arrest bleeding
Thrombin
activated normal protein/plts
Thrombin
Glanzmann’s Thrombasthenia
• Treatment:
Recombinant Factor VIIa
: induces thrombus formation using tissue factors/tissue dependent generators near the lesion to stop bleeding
Factor VIIa
: complete absence of fibrinogen
- Afibrinogenemia
: low level of fibrinogen
- Hypofibrinogenemia
: occurs during infancy and childhood
- Congenital
- Severe glycoprotein deficiency
(Congenital) Afibrinogenemia or Hypofibrinogenemia
(Congenital) Afibrinogenemia or Hypofibrinogenemia
• Laboratory:
a. Normal plt ct
b. Abnormal structure
larger platelets (gray to bluegray)
Gray platelet syndrome
normal platelet
Quebec Platelet Disorder
thrombocytopenia (consistent)
Gray platelet syndrome
abnormal proteolysis
Quebec Platelet Disorder
Gray platelet syndrome Laboratory
a. Prolonged Bleeding time
b. Decreased aggregation with all agents
Quebec Platelet Disorder Laboratory
a. Delayed (12-24 hrs) mucocutaneous bleeding
b. Thrombocytopenia (inconsistent)
WASp mutation
WiskottAldrich
Mutation in Ch 19
HermanskyPudlak
Mutation in Ch 13
Chediak Higashi
Mutation in RBM8A
TAR Syndrome
small platelets
WiskottAldrich
Swiss cheese platelet
HermanskyPudlak
fused granules of lysosome
Chediak Higashi
normal platelet
TAR Syndrome
WiskottAldrich
Triad of Symptoms
Thrombocytopenia
Recurrent infxn
Eczema
HermanskyPudlak
Triad of Symptoms
Occulocutaneous albinism
Ceroid-like pigment in macrophage
Bleeding tendency
Chediak Higashi
Triad of Symptoms
Albinism
Recurrent infection
Giant lysosomes
TAR Syndrome
Triad of Symptoms
Thrombocytopenia
Absence/hypoplasia of radial bones
Abnormal aggregation (congenital)
• Deficiency of alpha granules
Gray platelet syndrome
Gray platelet syndrome
• Characterized by
a) larger platelets colored gray to blue-gray, and a) thrombocytopenia
Gray platelet syndrome
• Laboratory:
a. Prolonged Bleeding time
b. Decreased aggregation with all agents
• Autosomal dominant disorder characterized by abnormal proteolysis & deficiency of alpha granules
Quebec Platelet Disorder
Quebec Platelet Disorder
• Characterized by
a) normal platelet, and b) abnormal proteolysis
Enzymes are abnormal because they target the alpha granules and degrades it even if not in use
Quebec Platelet Disorder
Alpha granules are stimulated to release content, but here, it is degraded and proeteolysed
Quebec Platelet Disorder
• Characterized by delayed (12-24 hrs) mucocutaneous bleeding. - Not onset
Quebec Platelet Disorder
Quebec Platelet Disorder
• Laboratory:
a. Thrombocytoenia (inconsistent)
(Sex-linked) deficiency dense granules, with a defect in cytoskeletal assembly.
Wiskott-Aldrich syndrome
Characterized by predominance of small platelets
Wiskott-Aldrich syndrome
• Triad of Symptoms include
- thrombocytopenia, recurrent infection & eczema
Wiskott-Aldrich syndrome
Remodels cytoskeleton
Wiskott-Aldrich Protein (WASp)
Assembly of cytoskeleton becomes defective
Wiskott-Aldrich Protein (WASp)
Wiskott-Aldrich Protein (WASp) Plt cannot activate not conrtact resulting to impaired
1) migration, 2) adhesion, and 1) interaction
Deficiency of dense granules
HermanskyPudlak syndrome
Chediak-Higashi
Triad of symptom include oculocutaneous albinism, accumulation of ceroid-like pigment in macrophages & bleeding tendencies
HermanskyPudlak syndrome
Plt has marked dilation (enlargement of surface connecting system and dense tubular system resulting to cheese appearance
Swiss cheese platelet
First found when rats were injured when injected with lead acetate
Swiss cheese platelet
4 divisions of granules in the lysosome
Chediak-Higashi
Causes a generalized cell dysfunction
Chediak-Higashi
Cytoplasmic granule fusion - lysosome in the cytoplasm
Chediak-Higashi
May lead to lymphocytic proliferation in the liver cells, spleen, and marrow
Chediak-Higashi
Macrophage accumulates in the tissues
Chediak-Higashi
Pancytopenia: most dangerous; decrease in all blood cells
Chediak-Higashi
• Structural defect in beta granules with corresponding abnormal aggregation responses and thrombocytopenia
Thrombocytopenia with Absent Radii syndrome (TAR)
• Characterized by severe neonatal thrombocytopenia and congenital absence or extreme hypoplasia of the radial bones (most pronounced skeletal abnormality), cardiac and other skeletal abnormalities.
Thrombocytopenia with Absent Radii syndrome (TAR)
Very low platelet count = shortens plt production
Thrombocytopenia with Absent Radii syndrome (TAR)
: inside
phosphatidylserine (PS) & phosphatidylethanolamine (PE)
: outside
phosphatidylcholine
happens during activation of platelet
Flip
caused by an enzyme called scramblase
Flip
phosphatidylserine switches with phosphatidylcholine
Flip
phosphatidylserine and phosphatidylethanolamine in the outer leaflet facilitates the assembly of clotting factors in normal condition
Flip
Surface expression of phosphatidylserine is decreased
Scott syndrome
skipping the plt to be activated
Scott syndrome
Platelets are always in an activated state without prior activation.
Stormorken syndrome
keeps the plt inactivated
Stormorken syndrome
flip is normal
Stormorken syndrome
Defective amino phospholipid translocase
Stormorken syndrome
: responsible for bringing phosphatidylserine to go back inside during resting platelet (not inactivated)
translocase