Primary Hemostasis Flashcards
Stoppage of blood flow
Hemostasis
Normal volume of blood
5-6L
Cellular element of hemostasis that surrounds the vessel
Extravascular tissue factor (TF)
Cellular element of hemostasis where the blood flows
Vascular Intima
The stage of hemostasis that refers to the role of blood vessels and platelets
Primary Hemostasis
Two elements involved in Primary Hemostasis
Blood Vessels and Platelets
The final product of primary hemostasis
Platelet plug / Hemostatic plug
A general test performed to assess primary hemostasis
Bleeding Time
In platelet adhesion, platelets adhere to _
Collagen
Needed for normal platelet adhesion
vWF
Bridge between platelet and collagen
vWF
Bernard-Soulier disease is also known
Giant Platelet syndrome
Bernard-Soulier disease has a deficiency in the _ receptor for vWF
GPIB/IX/V
Refers to the morphologic and functional changes in platelets
Platelet Activation
In platelet activation, platelets become spherical with _ formation
Pseudopod
Elements responsible for the formation of actomyosin
Actin, myosin and Ca2+
A vasoconstrictor that stimulates platelet secretion
Thromboxane A2
A drug that inhibits cyclooxygenase
Aspirin
The eicosanoid pathway is otherwise known as
Thromboxane A2 Synthesis pathway / Arachidonic acid metabolism pathway
A substage of primary hemostasis which is responsible for the release of granules
Platelet secretion
Thromboxane A2 precursor
Arachidonic acid
Only Alpha granule deficiency
Gray platelet syndrome
Enumerate the dense granule deficiencies
- Hermansky-Pudlak
- Chediak-Higashi
- Wiskott-Aldrich Syndrome
Primary substance needed in platelet aggregation
Fibrinogen
Platelet receptor for fibrinogen
GPIIb/IIIa
Deficiency in GPIIbIIIa
Glanzmann’s thrombasthenia
End product of Secondary Hemostasis
Fibrin clot
The general test for assessing secondary hemostasis
Clotting time
Elements involved in secondary hemostasis
Coagulation Factors
it is the production and maturation of platelets
Megakaryopoiesis / Thrombopoiesis
The time it takes to complete process of megakaryopoiesis
5 days
Primary stimulatory protein for megakaryopoiesis
Thrombopoietin
Site for the sequestration (storage) of platelets
Spleen
The major organ that produces TPO
Liver
Normal Value of platelet count
150,000-400,000 /uL or 150-400 x10^9/L
What happens to the platelet count of the patient when there is Splenomegaly
Decreased platelet count
What happens to the platelet count of the patient when there is Splenectomy
Increased platelet count
Megakaryocyte progenitors resemble _ under light microscopy
Lymphocytes
Three megakaryocyte Progenitors
- BFU-Meg
- CFU-Meg
- LD-CFU- Meg
The first stage of endomitosis in the platelet maturation series
LD-CFU- Meg
A type of cell division wherein there is nuclear division, but no cytoplasmic division
Endomitosis
How many stages does the megakaryopoiesis have?
6
Last stage of megakaryopoiesis capable of endomitosis
Promegakaryocyte/ MK-II
Reason for the increased N: C ratio of platelet maturation series
Endomitosis
The largest blood cell in the bone marrow smear
Mature Megakaryocyte / MK-III
The largest blood cell in a normal peripheral blood smear
Monocytes
The largest blood cell
Megakaryocytes
The smallest blood cell fragment
Platelets / Thrombocytes
Diameter of mature megakaryocyte
40-120 um
Diameter of platelets
2-5 um
Not a true cell
Platelets
Parts of a platelet
- Chromomere
2. Hyalomere
The chromatin of MK II
Moderately condensed
Describe the platelet production if the megakaryocytes possess more nuclear lobes
Higher platelet production
The first stage where Demarcating Membrane System is first formed
Promegakaryocyte
Process wherein there is release of an abundance of platelet fragments
Platelet shedding
Mean Platelet volume
8-10 fL
Four areas of the platelets
PSOM
- Peripheral
- Sol-gel
- Organelle
- Membranous
The life span of platelets
10 days
The mean platelet volume is inversely proportional to _
Platelet count
MPV should be based on specimens that are _ hrs. old
1-4 hrs. old
The outermost layer of the platelets
Peripheral Zone
Another name of actomyosin
Thrombosthenin
Important in clot retraction
Actomyosin / Thrombosthenin
Area of the platelet containing microfilaments and microtubules
Sol-gel zone
Microfilaments in the sol-gel zone
Actin & Myosin
Microtubule in the sol-gel zone
Tubulin
The protein responsible for the maintenance of the platelet’s disc shape/cytoskeleton
Tubulin
Area of the platelet where granules are located
Organelle zone
Two types of membranous system
- Open Canalicular System (Surface connecting system)
2. Dense Tubular System
Part of the membranous system where the eicosanoid pathway occurs
Dense Tubular System
Part of the membranous system where the granules are released
Open Canalicular System (Surface connecting
Smallest blood vessel
Capillaries
Signifies capillary fragility characterized by pinpoint hemorrhagic spots
Petechiae
The no. of petechiae is _ proportional to the platelet count
Inversely
Difference of purpura and ecchymosis
Size of skin
- Purpura-small areas of skin
- Ecchymosis- large areas of skin
The most common complication in venipuncture
Ecchymosis
Bloody stool associated with lower GIT bleeding characterized by a red-colored stool
Hematochezia
Bloody stool associated with upper GIT bleeding characterized by a black tarry stool
Melena
Excessive menstrual bleeding
Menorrhagia
Epistaxis which persists for >_min. may be a manifestation of a hemostatic disorder
> 15 min.
Occurs as a result of skin fragility
Simple purpura (Devil’s pinches)
Type of primary purpura characterized by the development of cayenne pepper petechiae
Schamberg’s purpura (Progressive pigmentary purpura)
Purpura that is not associated with any specific disease
Primary purpura
Purpura that applies to a rapid onset
Purpura fulminans
Purpura that may be seen in endocarditis, and ecthyma gangrenosum
Septic emboli
Blood clots containing bacteria
Septic emboli
Henoch-Schonlein purpura in an/a _ type of purpura
Allergic
Scurvy is associated with what deficiency?
Vitamin C
An increased corticosteroid excess that results in purpura
Cushing Syndrome
Purpura secondary to dysproteinemia characterized by hemosiderin staining of the skin similar to Schamberg’s
Waldestrom’s purpura
An autosomal dominant disorder characterized by hyperdistensible joints and fragile skin
Ehler’s-Danlos Syndrome
A defective disorder due to the mutation of fibrillin
Marfan’s Syndrome
Functional abnormalities of platelets
Qualitative platelet disorder
Receptor for vWF
GPIB
The most severe type of von Willebrand Disease
Type 3 (Complete deficiency of vWF)
Type of von Willebrand disease characterized by increased binding of factor VIII to vWF
Type 2N
Classic test to differentiate Bernard-Soulier syndrome and von Willebrand disease against Glanzmann’s Thrombasthenia
Platelet aggregation test
Deficiencies seen in von Willebrand disease
Factor VIII and vWF
Storage pool defect that demonstrates the smallest platelet
Wiskott-Aldrich Syndrome
Characterized by a decreased functional platelet factor V, and normal plasma factor V
Quebec platelet disorder
Low platelet count
Thrombocytopenia
Platelets that are produced as compensation to platelet consumption
Stress / Reticulated platelets
Four causes of thrombocytopenia
- Decreased platelet production
- Peripheral platelet destruction
- Abnormal platelet distribution
- Dilution of platelet count
Increased platelet production
Thrombocytosis
Classification of thrombocytosis characterized by a moderate increase (401-600x10^9/L)
Reactive thrombocytosis
Classification of thrombocytosis characterized by a marked increase (>601x10^9/L)
Autonomous thrombocytosis
Best anticoagulant for quantitative platelet evaluation (platelet count)
Citrate
Most common anticoagulant for quantitative platelet evaluation (platelet count)
EDTA
Most frequently involved leukocyte in platelet satellitosis
Neutrophils
Remedy for platelet satellitosis
Recollect in a citrated tube (Sodium citrate)
Components of the Reese-Ecker diluting fluid
- Sodium citrate (prevents coagulation)
- Formaldehyde (preservative)
- Brillant Cresyl Blue (dye)
Best microscope for the evaluation of platelet morphology
Phase-Contrast Microscope
Reference method for platelet count
Brecker-Cronkite
Thoma pipette utilized for platelet counting
Red Thoma Pipette (1:100)
Indirect platelet count is also known as
Platelet estimate
Three methods utilized for platelet estimate
- Fonio’s
- Dameshek
- Olef’s
In the platelet estimate, platelets are counted within how many fields?
10 fields
The average of 10 fields in the platelet estimates is multiplied to _
20,000
What should be the platelet count for PRP (platelet-rich plasma)
> 10,000/uL
Best promoter of platelet adhesion in vitro
Glass
Best promoter of platelet adhesion in vivo
Collagen
This platelet retention test tests the retention of platelets within the glass bead column
Salzmann method
The test used to measure the entire platelet function
Clot retraction
Rumpel-Leede is otherwise known as _, uses a tourniquet to measure capillaries to resist pressure
Hess test / Positive pressure technique
Pressure applied for the Rumpel-Leede test
100 mmHg for 5 min (Count petechiae after 15-30 min.)
Qualitative test for platelets which may be assessed by the presence of dumpling/droplet-like serum on the surface of the blood drop within 14-45 min.
Hirshboeck or Castor Oil Method
It is an in vivo measure of primary hemostasis
Bleeding time
Factor that is not a protein
Factor IV
What are the stages involved in primary hemostasis?
AASA
- Adhesion
- Activation
- Secretion
- Aggregation
Diseases related to platelet adhesion
- vWF deficiency
2. Bernard Soulier disease
What are the alpha granules in platelet secretion
BFA(2)TP(3)F(5)C
- Beta-thromboglobulin
- Fibronectin
- Albumin
- Alpha-2-antiplasmin
- Platelet Factor IV
- Platelet-derived growth factor
- Plasminogen
- FI
- FV
- FVIII
- vWF
- High Molecular Weight Kininogen
- C1 esterase inhibitor
What are the dense granules in platelet secretion
C2APAS+1
- Calcium
- Catecholamine
- ADP
- Pyrophosphate
- ATP
- Serotonin
- Magnesium
What are the Lysosomal granules in platelet secretion?
BAN
- Bacteriocidal enzymes
- Acid Hydrolase
- Neutral Protease
Granules released by platelets
ADLGM Alpha Dense Lysosomal Glycogen Membrane Phospholipid
Enumerate the megakaryopoietic stages:
- MK-I (Megakaryoblast)
- MK-II ( Promegakaryocyte)
- Granular Megakaryocyte
- MK- III (Mature Megakaryocyte)
- Metamegakaryocyte
- Platelet/Thrombocyte
Average size of platelets?
1-4um
Osteogenesis imperfecta is a rare autosomal dominant disorder characterized by mutation of genes that code for peptides of type _ collagen
Type 1
Involves the vessels throughout the body, which are dilated, tortuous (twisty/curvy), and disorganized
Hereditary hemorrhagic telangiectasia (Osler-Weber Rendu disease)
Tumors composed of blood vessels that swell and bleed at the surface
Congenital hemangiomata (Kasabach-Meritt syndrome)
Size of platelets in Bernard Soulier syndrome
> 20 um (Bernard is a giant bear = giant platelets)
The quantitative subtypes of vWF deficiency
Type 1 and 3
The qualitative subtype of vWF deficiency
Type 2
The initial treatment of choice for Von Willebrand’s disease
DDAVP
1-Desamino-8-D-Arginine Vasopressin also known as DESMOPRESSIN
The most preferred treatment for Von Willebrand disease
Humate P (contains intact vWF)
The treatment used for patients unresponsive to DDAVP
Cryoprecipitate
Type of von Willebrand disease with marked increased affinity for glycoprotein Ib
Type 2B
Subtypes of vWF disease Type 2
2A
2B
2M
2N
Type of von Willebrand disease with marked increased binding of Factor VIII to vWF
Type 2N
In platelet aggregation test, Glanzmann thrombasthenia will show a normal reaction in:
a. Epinephrine
b. Collagen
c. ADP
d. Ristocetin
d. Ristocetin
* Glanzmann will only show a normal reaction in ristocetin, and negative for all. On the other hand, Bernard Soulier will show a normal reaction in all EXCEPT ristocetin
The best test used to distinguish Hemophilia A from von Willebrand disease
Bleeding time
- Hemophilia = Normal ;VWD: Abnormal (primary hemostasis disorder)
Hemophilia A and Von Willebrand disease has this deficiency
Factor VIII deficiency
What is the point of distinction from other patients with the alpha-gamma storage pool defect from gray platelet syndrome?
Decreased platelet P-selectin (CD26P)
Disease wherein there is an impaired ability of platelets to promote coagulation due to the translocation of PS to the platelet outer membrane leaflet
Scott’s Syndrome
Causes of Thrombocytopenia
- Decreased platelet production in the BM
- Peripheral Platelet destruction
- Abnormal platelet distribution
- Dilution of platelet count
Components of the Guy-and Leake reagent for platelet count
- Sodium oxalate
- Formaldehyde
- Crystal Violet
Anticoagulant for Brecker Conkrite method?
1% Sodium Oxalate
Dilution in using unopette for platelet count
1:100 (use RBC Thoma pipette)
Platelets are counted in their relationship to red cells on a fixed smear
Indirect platelet count / Platelet estimate
Give the automation/s utilized in platelet count and their principle
- Voltage pulse counting -electrical impedance
2. Electro-optical counting - Flow cytometry
Significant platelet levels
<100,000/uL Abnormally low
<30,000-50,000/uL Bleeding with trauma
<30,000/uL Spontaneous bleeding
<5,000/uL Severe Spotaneous bleeding
Give a probable reason:
Normal platelet count and Prolonged Bleeding Time
Qualitative Platelet Abnormality (Adhesion, aggregation, storage pool defects)
Give a probable reason:
Low platelet count and Normal Bleeding Time
Autoimmune Thrombocytopenia (antiplatelets)
What is the sample for the platelet aggregation test?
Platelet Rich Plasma
Agonists in the platelet aggregation test
- Epinephrine
- Collagen
- ADP
- Ristocetin
Test considerations for Platelet Aggregation Test
- NO hemolysis
- Fasting for 8 hrs
- pH of 6.5-8.5
- No NSAIDS (Non-steroidal anti-inflammatory drugs)
- Within 3 hrs
Another name for the platelet retention test
Platelet adhesiveness test
Measures the entire function of platelets
Clot Retraction Test
Qualitative test for platelet retraction that uses castor oil to form “dimpling” / droplet like-serum on the surface of blood drop
Hirshboeck or castor oil method
The normal value for Hershboeck/castor oil method
15-45 min.
Capillary resistance test correlates with the degree of _
Thrombocytopenia
Rumpel-Leede Grading System
1+ = 0-10 petechiae 2+ = 10-20 petechiae 3+ = 20-50 petechiae 4+ = >50 petechiae
Suction cup method for capillary resistance utilizes a modified _ instrument
da Silva Melle instrument
What are the methods for bleeding time?
- Duke’s method
- Modified Ivy’s method
- Coply-lalitch method
- Adelson-Crosby method
- MacFarlane method
- Aspirin tolerance test
Which is more accurate for bleeding time?
Duke’s or modified Ivy’s method
Modified Ivy’s method because it uses a standard pressure of 40 mmHg
The normal value for the Duke’s bleeding time method
6-10 min. (blot every 30 seconds)
The best method to assess platelet adhesiveness
Modified Ivy method
The normal value for the Modified Ivy bleeding time method
3-6 min.
Where should you prick the patient when you are using modified ivy’s method?
The volar surface of the arm
Site of puncture for Macfarlane’s method
Earlobe
The pressure needed for modified Ivy’s method
40 mmHg
Difference of Stefanini method and McFarlane method for clot retraction
Stefanini method uses time intervals that begins in 1 hr, and ends within 18-24 hrs; McFarlane should be measured after 1 hr only.
