TESTS FOR AND DISORDERS OF PRIMARY HEMOSTASIS Flashcards
Normal platelet count
150 - 450 x 10^9/L
Is the most common cause of clinically important bleeding
Plt ct of <100,000 uL
Reference method for plt counting
Phase contrast microscope metho d
EDTA whole blood is diluted ___ : ___ with _% ____ to lyse the nonnucleated RBCs
1:100 ; 1% ammonium oxalate
Platelets are counted in the ___ ____ ____ of the ___ ___ ___ (1mm2) of he hemocytometer
25 small squares of the central large square
The charged hemocytometer is then placed in a moist chamber for ____ mins to allow platelets to settle
15 mins
Difference between the total cells counted on each side should be
<10%
Percentage difference formula
(V1-V2) / (V1 + V2 / 2) X 100
Platelet count formula
Cells counted x df / area (mm2) x depth (0.1)
A normal (wedge) blood smear should demonstrate approx
7 to 21 cells per 100x field
Platelet estimate formula
Average no of plts per field x total RBC count / 200 RBCs per field
Average number of RBCs per oil immersion field in the optimal assessment area
200
Designed to test platelet-rich plasma
Light-transmittance (optical) platelet aggregometry
PRP has a platelet count of
200,000 to 300,000/uL
Examples of aggregating reagents
Adenosine diphosphate
Collagen
Epinephrine
Ristocetin
Examples of disorders with NORMAL response of ADP, collagen, epinephrine
Bernard soulier syndrone
Von willerbrand disease
Examples of disorders with ABNORMAL response of ADP, collagen, epinephrine
GLANZMANN THROMBASTHENIA
Example of disorder with NORMAL response of Ristocetin
Glanzmann’s thrombasthenia
Example of disorder with ABNORMAL response of Ristocetin
BERNARD SOULIER SYNDROME
VON WILLEBRAND DISEASE
Example of disorder with ABNORMAL response of Ristocetin
BERNARD SOULIER SYNDROME
VON WILLEBRAND DISEASE
Measures platelet aggregation and ATP release (from dense granules)
Platelet lumiaggregometry
ATP oxidizes a firefly-derived ______ reagent to produce cold chemiluminescene proportional to the ATP concentration
Luciferin-luciferase reagent
Normal results in vascular disorder
Platelet cont
Platelet function test
Coagulation tests
Abnormal results in vascular disorders
Bleeding time
Rample-Leed test
Vascular disorders
Hereditary hemorrhagic telangiectasia
Helpers-Danilo’s Syndrome
Aka Rendu-Osler-Weber syndrome
Hereditary hemorrhagic telangiectasia
Aka cutis hyperelastica
Ehlers-Danilo’s syndrome
Most common inherited vascular bleeding disorder ; autosomal dominant ; with localized dilation of capillary walls
Hereditary hemorrhagic telangiectasia
Vascular disorder characterized by hyperextensible skin, hypermobile joints, joint laxity, fragile tissues, hematoma formation ; autosomal dominant
Ehlers-Danilo’s syndrome
Vascular disorder Most commonly seen in children ; most probably cause by immunologic damage to the endothelial cells ; characterized by gastrointestinal intestinal hemorrhage and joint swelling
Henoch schonlein purpura
Aka allergic purpura or non thrombocytopenia purpura
Henoch schonlein purpura
Vascular disorder characterized by defects in the synthesis of collagen and Hyaluronic acid ; vit C deficiency
Scurvy
Aka secondary thrombocytosis
Reactive thrombocytosis
Examples of cases with reactive thrombocytosis
Recovery from splenectomy
Acute blood loss
Major surgery
Characterized by MODERATELY increased platelet count
Reactive thrombocytosis
Aka primary thrombocytosis
Autonomous thrombocytosis
Characterized by MARKEDLY increased platelet count
Autonomous thrombocytosis
Examples of cases with autonomous thrombocytosis
Essential thrombocythemia
Chronic myelogenous leukemia
Polycythemia Vera
Primary myelofibrosis
Examples of cases with autonomous thrombocytosis
Essential thrombocythemia
Chronic myelogenous leukemia
Polycythemia Vera
Primary myelofibrosis
Examples of cases with autonomous thrombocytosis
Essential thrombocythemia
Chronic myelogenous leukemia
Polycythemia Vera
Primary myelofibrosis
Group of malignant neoplasms ; described as clonal proliferations of bone marrow stem cells ; characterized by elevations in or more myeloid cell types in the peripheral blood
Myeloproliferative neoplasm
Uncontrolled proliferation of bone marrow Megakaryocytes ; plt count exceeding 1 million / uL
Essential thrombocythemia
Most common congenital bleeding disorder
Von willebrand’s disease
Primary platelet surface receptor for VWF
GP Ib/IX/V
IMPORTANT IN PLATELET ADHESION
GP Ib/IX/V
VWF
Low factor VIII , normal PT , prolonged APTT , Normal aggregation ACE ; abnormal aggregation in Ristocetin
VWD
Normal or increased bleeding time ; mild bleeding tendency ; petechiae none ; MOST COMMON vWD
Type 1
Rarest type of VWD
Type III
Platelet adhesion disorders
Bernard soulier
VWD
Platelet aggregation disorders
Glanzmann’s thrombasthenia
Hereditary afibrinogenemia
Deficiency of GP IIb/IIIa
Glanzmann’s thrombasthenia
Very prolonged bleeding time ; abnormal clot retraction ; abnormal aggregation response in ACE ; normal aggregation response in Ristocetin
Glanzmann’s thrombasthenia
Process wherein platelets adhere to other platelets
Platelet aggregation
Important in platelet aggregation
GP IIb/IIIa
Fibrinogen
Thromboxane pathway disorders ; Cyclooxygenase and Thromboxane synthetase deficiency
Platelet secretion disorder
Alpha and dense granule deficiency
Pool storage diseases
Alpha granule deficiency ; autosomal recessive
Gray platelet syndrome
Characterized by plasma levels of platelet factor 4 and B-thromboglobulin is increased
Gray platelet syndrome
Autosomal dominant ; bleeding disorder that results from multimerin deficiency
Quebec platelet disorder
A protein stored in alpha granules associated with Quebec platelet disorder
Multimerin
Dense granules deficiency ; oculocutaneous albinism ; normal plt
Hermansky-Pudlak syndrome
Dense granules deficiency ; partial albinism ; low plt ct
Chediak-Higashi syndrome
Dense granules deficiency; no albinism ; low plt ct
Wiskott-Aldrich syndrome
Dense granules deficiency; no albinism ; normal plt ct
TAR syndrome
All of the dense granules deficiencies are autosomal ___ except for Wiskott-Aldrich syndrome which is ____ recessive
Autosomal recessive ; x-linked recessive
Plt count during infancy and within 1 year of birth in the case of Wiskott-Aldrich syndrome
Low in infancy and normal within 1 year of birth
Most common acquired bleeding disorder
Trauma-induced coagulopathy
