Coagulation Disorders: Primary
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Transcript Coagulation Disorders: Primary
MLAB 1227- COAGULATION
KERI BROPHY-MARTINEZ
Coagulation Disorders: Primary Hemostasis
CLINICAL MANIFESTATIONS OF BLEEDING
DISORDERS
Type of bleeding indicates which component of the hemostatic
system is
Defects in primary hemostasis
Easy bruising, petechiae (small dots), purpura (bleeding into the
skin), ecchymoses (large superficial hemorrhaging), and
spontaneous bleeding, especially from mucosal surfaces
Defects in secondary hemostasis
Prolonged deep bleeding into joints/muscles or hematomas: With
these disorders can see spontaneous bleeding (severe factor
deficiency) or post-injury (mild factor deficiency)
Combination
Multiple site bleeding occurs in severe combined defects (DIC).
Platelet activity and coag proteins are related so disorders of one
can affect the other since platelets provide phospholipid binding
sites for clotting factor interaction.
A: Petechiae
B: Ecchymosis
C: Hematoma
EVALUATION OF POTENTIAL BLEEDING
DISORDER
Obtain Medical history
Age of onset
Symptoms
Family history
Drug history
Exposure to toxins
Physical exam
Type and sites of bleeding
Spontaneous/ result of trauma
Order and interpret lab screening tests
Platelet count
PT
PTT
BT or PFA
VASCULAR SYSTEM DISORDERS
Defects may be due to abnormalities in the
endothelial cell lining of the blood
vessel(acquired) or the connective tissue
supporting the vessels(hereditary)
Symptoms
Superficial bleeding
Hemostatic testing is normal
VASCULAR DISORDERS
Inherited
Rare
Bleeding and easy bruising are common symptoms
Conditions
Marfan syndrome
Ehlers-Danlos syndrome
VASCULAR DISORDERS: ACQUIRED
Patient exhibits bruising and petechiae
In all acquired disorders, the patient exhibits
purpura.
Defects in vasculature is caused by:
Conditions that decrease the supportive connective
tissue in the blood vessel walls
Presence of abnormal proteins in the vascular tissues
Infections or allergic conditions
Mechanical stress
VASCULAR DISORDERS: ACQUIRED
Classification
Purpura due to decreased connective tissue
Collagen and elastin fibers, which form the
support for blood vessels, are lost, causing
fragility
Senile purpura( elderly people)
Scurvy ( deficiency of vitamin C)
Purpura associated with paraprotein disorders
Purpura due to vasculitis
Inflammation of small blood vessels due to
complement activation on subendothelium
drugs and infectious agents
PLATELET DISORDERS
Platelet
disorders are the most common
cause of abnormal bleeding.
Qualitative: abnormalities of platelet
function
Quantitative: platelet count is below or
above reference range
Hallmarks
Petechiae
Excess bleeding from superficial sites
Mucous membranes, skin
PLATELET ABNORMALITIES
Giant platelet
Agranular
platelet
QUANTITATIVE DISORDERS- ITS ALL
ABOUT THE NUMBERS..
Thrombocytopenia
Decrease in the number of circulating plateletsbelow 100,000/µL
Most common cause of clinical important bleeding
Symptom of underlying disease
Bleeding time is prolonged
PT, PTT not affected
QUANTITATIVE DISORDERS:
THROMBOCYTOPENIA
1.
Increased destruction : bone marrow function is normal
Immune Mediated Destruction
Immune Thrombocytopenic Purpura (ITP):
Caused by antibodies that cover the platelets
Acute and chronic forms
Resulting from an unknown cause (Idiopathic)
Often follows a viral infection
Believed to be antibody mediated, may produce a
specific platelet autoantibody, specifically IgG.
Spontaneous remission occurs in approximately
80% of the cases
Alloimmune Thrombocytopenia
Alloantibodies stimulated by foreign antigens cause
destruction
ACUTE VS. CHRONIC ITP
Acute ITP
Chronic ITP
Predominantly in children,
following viral illness
Adults aged 20-50 years
Idiopathic
Sudden onset
Lasts les than 6 months
Insidious onset
Lasts more than 6 months
Platelet counts <20,000/µL
Platelet counts 30,000/µL80,000/µL
Petechiae, ecchymoses,
mucosal bleeding
Mucosal bleeding, easy
bruising, petechiae
Affects both sexes equally
Prevalence in females
QUANTITATIVE DISORDERS:
THROMBOCYTOPENIA (CON’T)
Drugs
HIT: Heparin Induced Thrombocytopenia
Heparin causes platelets to activate which
eventually causes antibodies to target the
heparin/PF4 complex
Results in thrombocytopenia
Other Diseases
Collagen disorders
LE, RA
Infections
Infectious Mononucleosis
HIV
QUANTITATIVE DISORDERS:
THROMBOCYTOPENIA
Nonimmune: excessive consumption
Platelets are activated without the cascade
activating
TTP: Thrombotic Thrombocytopenic Purpura
DIC: Disseminated intravascular coagulation
HUS: Hemolytic uremic syndrome
Mechanical destruction by artificial heart
valves
QUANTITATIVE DISORDERS:
THROMBOCYTOPENIA
Decreased production : bone marrow is abnormal
bone marrow impairment, radiation, malignancy,
drugs, congenital conditions
3. Abnormal distribution
sequestering by the spleen or liver
3. Excessive dilution
transfusions of stored blood or plasma expanders
3. Conditions with multiple mechanisms of
2.
thrombocytopenia
Example: Alcoholism: Patients that have cirrhosis
present, can have problems with the coagulation proteins as
well as their platelets. Alcohol reduces platelet numbers and
causes defects of aggregation, release and procoagulant
activity. Platelet production is suppressed by the toxic effect
of alcohol on the bone marrow.
QUANTITATIVE DISORDERS
Thrombocytosis
Temporary rise in the number of circulating platelets
Plateletshave normal function.
Counts > 1000 x 103/mL
Primary thrombocytosis: uncontrolled production of
megakaryocytes
CML
Polycythemia vera
Essential thrombocythemia
Secondary or reactive thrombocytosis: due to another
disease or condition
Surgery, particularly splenectomy ( since spleen normally
contains 20-30% of the platelets
Inflammation
Acute blood loss
Exercise
ESSENTIAL THROMBOCYTHEMIA
Clonal disorder
Results in very high platelet counts (> 1 million)
Results in variable-sized platelets
Seen in middle-aged population, both men and
women
Clinical signs
Hemorrhage
Platelet dysfunction
Thrombosis
QUALITATIVE DISORDERS: FUNCTIONAL
Manifestations include:
Petechiae
Easy and spontaneous bleeding from mucous
membranes
Prolonged bleeding from trauma
Lab Diagnosis
Platelet count is normal to slightly decreased
Prolonged bleeding time
PT, PTT, Fibrinolysis tests are normal
Platelet aggregation studies variable
INHERITED DISORDERS OF PLATELET
FUNCTION
Disorders of adhesion
Defects in platelet-vessel wall interaction
Disorders of aggregation
Defects in platelet-platelet interaction
Disorders of platelet secretion and abnormalities
of granules
Disorders of platelet secretion and signal
transduction
Disorders of platelet coagulant-protein
interaction
QUALITATIVE (FUNCTIONAL) DISORDERS:
INHERITED
Disorders of Platelet Adhesion: platelet to vessel
wall interaction
Bernard-Soulier syndrome
Deficiency of a membrane glycoprotein (GPIb/IX)
Giant platelets with coarse granulation and vacules may
be seen.
Platelet adhesion, aggregation and bleeding time/ PFA-100
are abnormal
No treatment available, only supportive measures
Von Willebrand’s disease
Deficiency of the von Willebrand factor(vWF) OR production
of a dysfunctional protein
Abnormal platelet adhesion and bleeding time/PFA-100 as
well as abnormal PTT ( due to VIII defect)
Bernard-Soulier syndrome
@2007 Rector and Visitors of the University of Virginia
Charles E. Hess, M.D and Lindsey Krstic, B.A.
QUALITATIVE (FUNCTIONAL) DISORDERS:
INHERITED
Disorders of Platelet Aggregation: platelet to
platelet interaction
Glanzmann’s thrombasthenia
Deficiency of thrombasthenin
Lack the GPIIb/IIIa complex, which is where fibrinogen
attaches to platelet surface
Abnormal platelet aggregation, clot retraction and bleeding
time
Absence of Fibrinogen
QUALITATIVE (FUNCTIONAL) DISORDERS:
INHERITED
Disorders of Platelet Secretion, Abnormalities of granules
and Signal transduction
Deficiencies of Dense Granules
Storage pool disease
Platelets appear normal on peripheral smear, but
there is a decrease or absence of dense granules
Platelet aggregation abnormal
Deficiencies of Alpha Granules
Gray Platelet Syndrome
Agranular platelets
Defective Thromboxane A2 Synthesis
Platelet secretion and aggregation affected
Defects in Signal transduction
Affects platelet to agonist interactions
QUALITATIVE (FUNCTIONAL) DISORDERS:
INHERITED
Disorders of Platelet Procoagulant Activity
Scott syndrome
Activated platelets secrete and aggregate normally
but fail to bind coagulation factors
INHERITED PLATELET DISORDERS
Disorder
Defective
Platelet
Component
Platelet
Count
BT/PFA-100
Other
Bernard- Soulier
Syndrome
Glycoprotein
Ib/IX
Normal or
decreased
Increased
Giant platelets
Glanzman
thrombasthenia
Glycoprotein
IIb/IIIa
Normal
Increased
Storage pool
disease
Dense granule
deficiency
Normal
Increased
Gray Platelet
syndrome
Alpha granule
deficiency
Decreased
Variable
Defective
thromboxane A2
synthesis
Deficiency of
cyclooxygenase,
or TXA2
synthase
Normal
Increased
Agranular
platelets
QUALITATIVE DISORDERS:
ACQUIRED
Uremia
Liver Disease/Alcohol
Reduction in clotting proteins, platelets
Hematologic Disorders
Presence of toxin or waste products affects action of
platelets
Myeloproliferative Disorders, Acute leukemias,
myelodysplasia, multiple myeloma and macroglobulinemia
Drugs
Aspirin: prevents the release of thromboxane A2, thus
decreasing platelet secretion. Those platelets affected by
aspirin still circulate but are nonfunctional
Antibiotics: penicillins & cephalosporins. Drug coats the
platelet membrane blocking ADP and epinephrine
receptors, so platelet can not respond to agonist.
SCREENING TESTS OF PRIMARY
HEMOSTASIS
Platelet
Count
PT
aPTT
Template
BT
Vascular
Disorders
Normal
Normal
Normal
Normal or
abnormal
Thrombocytopenia
Decreased
Normal
Normal
Abnormal
Platelet
Dysfunction
Usually
normal
Normal
Normal
Normal or
abnormal
VASCULAR DAMAGE
Platelet Adhesion
Bleeding Time
Von Willebrand Disease
PFA-100
Bernard-Soulier
Platelet Activation/Release
Aggregometry
Storage-pool disease
PFA-100
Aspirin/ Certain other drugs
Platelet Aggregation/Thrombin Generation
TEG
Glanzmann’s thrombasthenia
REFERENCES
@2007 Rector and Visitors of the University of
Virginia Charles E. Hess, M.D and Lindsey
Krstic, B.A
Castellone, D. D. (2010, October). Complexities of
Immune Platelet Disorders. Advance for
Administrators of the Laboratory, 19(10), 27-30.
http://image.bloodline.net/stories/storyReader$61
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