MLAB C OAGULATION K ERI B ROPHY -M ARTINEZ Coagulation Disorders: Primary Hemostasis

C LINICAL MANIFESTATIONS OF B LEEDING D ISORDERS 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

E VALUATION OF P OTENTIAL B LEEDING D ISORDER 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

V ASCULAR S YSTEM D ISORDERS 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

V ASCULAR D ISORDERS Inherited Rare Bleeding and easy bruising are common symptoms Conditions Marfan syndrome Ehlers-Danlos syndrome

V ASCULAR D ISORDERS : A CQUIRED 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

V ASCULAR D ISORDERS : 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

P LATELET 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

P LATELET A BNORMALITIES Agranular platelet Giant platelet

Q UANTITATIVE D ISORDERS - I TS A LL A BOUT THE N UMBERS.. Thrombocytopenia Decrease in the number of circulating platelets- below 100,000/µL Most common cause of clinical important bleeding Symptom of underlying disease Bleeding time is prolonged PT, PTT not affected

Q UANTITATIVE D ISORDERS : T HROMBOCYTOPENIA 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

A CUTE VS. C HRONIC ITP Acute ITPChronic ITP Predominantly in children, following viral illness Adults aged 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/ µL- 80,000/µL Petechiae, ecchymoses, mucosal bleeding Mucosal bleeding, easy bruising, petechiae Affects both sexes equallyPrevalence in females

Q UANTITATIVE D ISORDERS : T HROMBOCYTOPENIA (C ON ’ 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

Q UANTITATIVE D ISORDERS : T HROMBOCYTOPENIA 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

Q UANTITATIVE D ISORDERS : T HROMBOCYTOPENIA 2. 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 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.

Q UANTITATIVE D ISORDERS Thrombocytosis Temporary rise in the number of circulating platelets Plateletshave normal function. Counts > 1000 x 10 3 /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

E SSENTIAL T HROMBOCYTHEMIA 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

Q UALITATIVE D ISORDERS : F UNCTIONAL 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

I NHERITED D ISORDERS OF P LATELET F UNCTION 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

Q UALITATIVE (F UNCTIONAL ) D ISORDERS : I NHERITED 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 Rector and Visitors of the University of Virginia Charles E. Hess, M.D and Lindsey Krstic, B.A.

Q UALITATIVE (F UNCTIONAL ) D ISORDERS : I NHERITED 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

Q UALITATIVE (F UNCTIONAL ) D ISORDERS : I NHERITED 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 A 2 Synthesis Platelet secretion and aggregation affected Defects in Signal transduction Affects platelet to agonist interactions

Q UALITATIVE (F UNCTIONAL ) D ISORDERS : I NHERITED Disorders of Platelet Procoagulant Activity Scott syndrome Activated platelets secrete and aggregate normally but fail to bind coagulation factors

I NHERITED P LATELET D ISORDERS DisorderDefective Platelet Component Platelet Count BT/PFA-100Other Bernard- Soulier Syndrome Glycoprotein Ib/IX Normal or decreased IncreasedGiant platelets Glanzman thrombasthenia Glycoprotein IIb/IIIa NormalIncreased Storage pool disease Dense granule deficiency NormalIncreased Gray Platelet syndrome Alpha granule deficiency DecreasedVariableAgranular platelets Defective thromboxane A 2 synthesis Deficiency of cyclooxygenase, or TXA 2 synthase NormalIncreased

Q UALITATIVE D ISORDERS : A CQUIRED Uremia Presence of toxin or waste products affects action of platelets Liver Disease/Alcohol Reduction in clotting proteins, platelets Hematologic Disorders Myeloproliferative Disorders, Acute leukemias, myelodysplasia, multiple myeloma and macroglobulinemia Drugs Aspirin: prevents the release of thromboxane A 2, 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.

S CREENING T ESTS OF P RIMARY HEMOSTASIS Platelet Count PTaPTTTemplate BT Vascular Disorders Normal Normal or abnormal ThrombocytopeniaDecreasedNormal Abnormal Platelet Dysfunction Usually normal Normal Normal or abnormal

V ASCULAR D AMAGE Platelet Aggregation/Thrombin Generation TEG Glanzmann’s thrombasthenia Platelet Activation/Release Aggregometry PFA-100 Storage-pool disease Aspirin/ Certain other drugs Platelet Adhesion Bleeding Time PFA-100 Von Willebrand Disease Bernard-Soulier

R 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),