Approach to bleeding By Assoc. Prof. Darintr Sosothikul, MD Pediatric Hematology-Oncology division, King Chulalongkorn Memorial Hospital, Faculty of Medicine, Chulalongkorn University
The mechanism of hemostasis Blood vessel Platelet Blood flow Coagulation adhesion VWF aggregation activation Fibrin IIa IIase Xase FVIIa TF Subendothelial matrix Vessel injury Hemostatic plug Courtesy of Dr Shima 2
Primary Hemostasis Stable Platelet adhesion/ Platelet Rolling: GPIb/VWF GPVI+α2β1/collagen activation/aggregation: GPIIb/IIIa Blood Flow Platelet adhesion: GPIb/VWF VWF VWF collagen VWF VWF collagen VWF collagen VWF collagen WHF
Platelet Binding site for vwf GpI X GpIb Open canalicular system Mitochondrion GpIIb/IIIa Binding site for Fibrinogen and vwf Lysosome Alpha-granules Fibrinogen,vWF,PDGF, PF4 and P-selectin Glycogen Dense bodies ADP,ATP,ionized calcium and serotonin Microtubules
Cell-based Model 2000S VIII/VWF- VIIIa V-Va XI-XIa platelet Two main functions of TF to activate factor X to Xa to activate factor IX to IXa Hoffman M, Monroe DM Thromb Haemost 2001:958-65 Robert HR,et al Anesthesiology 2004:722-30
Cell-based Model 2000S Thrombin Hoffman M, Monroe DM Thromb Haemost 2001:958-65 Robert HR,et al Anesthesiology 2004:722-30
Fibrinolytic system tpa: tissue plasminogen activator PAI-1: Plasminogen activator inhibitor Adapted from Wiman MFR 1987
Control Mechanisms 1) TF pathway inhibitor 2) Protein CS system 3) Antithrombin 4) Glycoaminoglycans APC: activated protein C AT: antithrombin GAG: glycoaminoglycans T: thrombin PC: protein C S: protein S TF: tissue factor TM: thrombomodulin
Approach to the Bleeding patient Detailed history Is a bleeding tendency present? Is the condition familial or acquired? Is the disorder affecting primary or secondary hemostasis? Is there underlying systemic disease causing or exacerbating the bleeding tendency? Is the increased bleeding pharmacologically induced?
Patterns of Clinical Bleeding in Disorders of Hemostasis Characteristic Onset of bleeding Sites of bleeding Skin Mucous membranes Other sites Disorders of 1º Hemostasis ( Platelet-Vascular) Spontaneous or immediately after trauma Superficial surfaces Petechiae, ecchymosis Common (Oral, nasal) Rare Disorders of 2º Hemostasis ( Coagulation Factor) Delayed after trauma Deep tissues Hematomas Rare Common (joint,muscle) Bleeding stop after pressure Yes No
Congenital coagulopathies and Qualitative thrombocytopathies Sex-Linked Recessive Hemophilia A (factor VIII deficiency) Hemophilia B (factor IX deficiency) Wiskott-Aldrich syndrome Autosomal Dominant von Willebrand Disease Osler-Weber-Rendu syndrome (hereditary hemorrhagic telangiectasia) Dysfibrinogenemias Autosomal Recessive Disorders Deficiencies in factor II, V, VII, XI, X, or XIII α2-antiplasmin deficiency Bernard-Soulier syndrome Glanzmann s thrombasthenia Gray platelet syndrome Afibrinogenemia Hypofibrinogenemia Type 3 von Willebrand disease
Platelet / Vascular defect Mucocutaneous bleeding
Coagulation defect CNS bleeding/ deep tissue or hemarthrosis
Purpura fulminans
Laboratory evaluation; screening tests CBC: quantitative assessment of platelets Bleeding time Prothrombin time (PT) assay and INR Activated partial thromboplastin time (aptt) Thrombin time or Fibrinogen level Small size of platelet Normal size of platelet Giant platelet
Pre-analytic errors Problems with blue-top Biological effects tube Hct > 55% or < 15% Partial fill tubes Lipidemia Vacuum leak and citrate Hyperbilirubinemia evaporation Hemolysis Problem with phlebotomy Laboratory errors Heparin contamination Delayed in testing Slow fill Prolonged incubation at 37C Vigorous shaking Freeze/Thaw deterioration
Developmental hemostasis Contact factors: XII, X, HMWK and vitamin K dependent: FII, VII, IX, X are decreased until 6 months of age Thrombin generation is decreased 30 50% compared with adult levels Neonatal platelets are to be hyporeactive to thrombin, ADP, epinephrine, and TXA 2 due a defect intrinsic to neonatal platelets Kids are not little adults: the differences Andrew M,et al. Blood 1992;80(8):1998 2005 Massicotte MP, et al.thromb Res 2006;118(1):153 63 Rajasekhar D, et al Thromb Haemost 1997;77(5):1002 7
Pediatric reference values for molecular markers in hemostasis Sosothikul D, Seksarn P, Lusher JM. J Pediatr Hematol Oncol. 2007 :19-22
Mixing study A 1:1 mixing study is done when the PT/PTT is prolonged. The patient's plasma is mixed with normal plasma and the abnormal test is repeated. If the mixing of normal plasma corrects the abnormal test, then a factor deficiency is suggested; otherwise, an inhibitor is suspected.
Case study A 5-year-old girl presents with multiple large ecchymoses on both arms and legs. No family history of bleeding tendency PE shows many dental caries with gum bleeding. Otherwise are normal.
Laboratory investigation Case study CBC: Hb 12.5 g/dl MCV 82 Fl, MCH 29 pg, MCHC 33%,RDW 12%, WBC 12,300 / µl (N56,L12,E32%) and Platelet 250,000/ µl
Laboratory investigation What further investigations are required for definite diagnosis? Bleeding time 14 min Platelet aggregation test Stool exam for parasites: ascaris eggs
Platelet Aggregation Test ADP Collagen
PLATELET Platelet Gplb/IX vwf ADHESION DISORDERS vwd Bernard-Soulier syr. ADP TXA Platelet release defect Storage pool disease RELEASE Platelet GplIb/IIIa Fibrinogen AGGREGATION Glanzmann s thrombasthemia
Acquired platelet dysfunction with eosinophilia (APDE) acquired platelet function defect It was first described by Mitrakul and Suvatte in 1975. Unknown etiology. It has been speculated that the high IgE is in response to parasite causes mediated mast cell degranulation and leads to in-vivo platelet activation. Platelet function tests show variable storage pool defects.
Clinical manifestations Spontaneous bruising on the extremities off and on for a duration of weeks or months The purpura is shown as purpuric spots or medium size ecchymoses. Mucosal bleeding eg. epistaxis, gum bleeding No spontaneous intracranial hemorrhage. Bleeding symptoms in most patient are mild, transient with spontaneous recovery.
APDE: management Spontaneous recovery within 6 months. Avoid trauma and injury; identification card Transfusion of platelet concentrate are given only when undergoing surgery. Reassure the parent about the prognosis and alert them to accidents. Common intestinal parasites are usually removed by giving antihelminthic drugs.
Case study A full- term neonate male presented with seizure and pale PE: Marked pale conjuctivae,tense anterior fontanalle and cephalhematoma
Pedigree
Case study What further investigations are indicated? CBC: Hb 7.5 g/dl, Hct 22%, MCV 100 fl. WBC 12,500 (N55,L40,Mo5) and platelets 300,000/µl Coagulogram: PT 12 s (c 11-14 s) aptt 90 s (c 33-40 s) and TT 11 (c 11-13 s) Factor VIII < 1 %
CT brain: Case study
Case study How would you treat this patient? Factor VIII replacement: Factor VIII conc 50 units/kg every 8-12 hr, LD-PRC 10-15 ml/kg and anticonvulsants
Principles of care in Hemophilia Prevention of bleeding should be the goal, ideally by prophylaxis Acute bleeds should be treated early Home therapy should be used to manage only uncomplicated bleeding episodes Use a safe and effective FVIII concentrate with good supply line Regular exercise should be encouraged to promote strong muscles,protect joints and improve fitness WFH,Guidelines for the Management of Hemophilia 2005
When to introduce prophylaxis? The earlier, the better is the long-term outcome The earlier prophylaxis is started, the better the long-term outcome Primary prophylaxis may prevent recurrent bleeding and chronic arthropathy Secondary prophylaxis slows, but does not prevent, ongoing joint damage Astermark J, et al. Br J Haematol. 1999;105(4):1109-1113. Van den Berg HM, et al. Haemophilia. 2006;12(Suppl 3):159-168.
Case Study III A 2-year-old girl was referred for management of severe epistaxis. Having history of bleeding tendency in the family. No taking any medications.
Case Study III
Case study III CBC: Hb 9.9 g/dl MCV 68 fl, WBC 8,570/mm 3 (PMN 35 %, Band 1%, LL 26%, L 34%, Mo 4%), platelet count 274,000/mm 3 Bleeding time 15 min.(n 2-7) Coagulogram: aptt of 29 sec. (control 27.8) and PT 11.5 sec. (control 12) vwd work up: VWF: Ag 33 % (N=50-150%) VWF: Rco < 5 % (N=50-150%) VWF:CBA 22 % (N=50-150%) F VIII:C 50 % (N=50-150%)
Case study III vwf Multimers High moleular weight multimer Low moleular weight multimer Normal Patient Diagnosis: Von Willebrand disease type 2 A
Classification of VWD Type 1 (AD); represents 80% of cases Type 2 (AD,AR);15-20 % Type 2A (AD,AR) Type 2B (AD) Type 2M (AD,AR) Type 2N (AR) Type 3 (AR); severe type Partial quantitative deficiency of apparently normal vwf Qualitative deficiency of vwf Decreased VWF-dependent platelet adhesion with selective deficiency high molecular weight multimers (HMWM) Increased affinity for platelet glycoprotein Ib Decreased vwf-dependent platelet function without selective deficiency HMWM Markedly decreased binding affinity for factor VIII Virtually complete deficiency of vwf Sadler JE. J Thromb Haemost 2006; 4: 2103-14
Treatment of VWD DDAVP (deamino-8- arginine vasopressin) plasma VWF levels by stimulating secretion from endothelium Maximal rise of vwf and FVIII is observed in 30-60 minutes Typical maximal rise is 2- to 4-fold for vwf and 3- to 6-fold for FVIII Minirin Dosage 0.3 µg/kg in NSS 50 ml IV in 30 min q 12 hr Stimate Intranasal 150 µg in children less than 50 kg. 1,500 mcg/ml 100 mcg/ml Minirin
Treatment of VWD Cryoprecipitate Source of fibrinogen, factor VIII and VWF Only plasma fraction that consistently contains VWF multimers Factor VIII concentrate (Intermediate purity) Alphanate and Immunate Virally inactivated product Contain a near-normal complement of high molecular weight vwf multimers Antifibrinolytic drugs, preventing rapid clot dissolution Platelet transfusions May be helpful with vwd type 2B or refractory to other therapies
T H A A N K S