Practical Hematology Treating - PowerPoint Presentation

Slide1

Practical HematologyTreating Coagulopathy

Wendy Blount, DVMSlide2

Practical Hematology

Anemia 101

Blood Loss Anemia

Hemolysis

Non-Regenerative Anemias

Transfusion Medicine

Polycythemia

Bone Marrow Disease

Coagulopathy

Central IV Lines

Leukophilia

Leukopenias

Splenic DiseaseSlide3

Assessment of CoagulationIs bleeding appropriate to injury or pathology?

Control arterial bleeding with ligation

If not, assess coag status ASAP

Platelet count

PT, PTT/ACT

BMBT

FDPs, d-dimers

Factor assays & DNA

Tests

Cornell Comparative Coag for crazy stuffSlide4

Treating Primary Hemostatic DefectsSimulate primary hemostasis until secondary can kick inDirect pressure (bandages)Topical epinephrineCauterize – AgNitrate, Styptic, Electrocautery

J0313 – cautery + 3 tips + case $72.00

J0313A – cautery <$40.00

J0313W, J0313 X, J0313Y, J0313Z – replacements tips <$15

J0313D1 – sterile sleeves, 10 for $30

Runs on 2AA batteriesSlide5

Treating Primary Hemostatic DefectsSimulate primary hemostasis until secondary can kick inDirect pressure (bandages)Topical epinephrinecauterizeTreat hypovolemiaColloids and fluids with packed cells or Oxyglobin

Whole blood transfusion

Identify and treat cause

Vasculitis

Thrombocytopenia <20-50,000/ul

Platelet function defectSlide6

Treating Primary Hemostatic DefectsSupportive therapyCage rest – avoid injuryAvoid poking holes in big veins or any arteriesSlide7

1st Round Treatment - VasculitisRound 1 Tests: CBC, panel, UA, assess proteinuria, Urine C&S, FeLV/FIV, HWTestTreat underlying cause if obvious

Doxycycline 5-10 mg/kg PO BID x 3 weeks

If response, may need to treat as long as 6 weeks total

Anti-inflammatory prednisone only if chronic infection ruled out by imaging, culture, & appropriate PCRs or other tests

0.5 mg/lb/day

prednisone

Monitor for improvement of clinical signs for 2-4 weeksSlide8

2nd Round Treatment - VasculitisRound 2 Tests: infectious Disease testingEchocardiogram, blood C&S during fever

Tick panels, Bartonella, Brucella

Mira Vista Fungal Tests

Consider bone marrow, skin biopsy, anti-platelet antibody, ANA

Treat underlying cause

May

need to increase to immunosuppressive prednisone

1-2 mg/lb/day

Highest dose no longer than 2 weeks

Primary

IM

cases respond within

a week

Wean off over 2-3 months or moreSlide9

3rd Round Treatment - VasculitisIf first bone marrow showed no increase in megakaryocytes, can repeat in 1-2 weeksPersistent lack of megakaryocytes when IMT is suspected – antimegakaryocyte Ab assay

Repeat diagnostics looking for infection after immunosuppressive therapy for 1-2 weeks

X-rays, abdominal ultrasound, GlobalFAST®

Urine

culture, blood culture, other inf dz testsSlide10

3rd Round Treatment - VasculitisIf suspecting infectious disease, can take samples for paired seraIf suspecting

IM,

may need to add

azathioprine,

cyclosporine or Danazol

Vincristine 0.02 mg/kg IV q7days

Begin weaning when platelets reach 100,000/ul

Decrease one drug every 1-2 weeks, checking CBC

Wean off drugs over 3-6

monthsSlide11

Rosalie Cooper-ChaseCrockett TXSlide12

von Willebrand DiseaseTreat when bleeding from injury, or perioperativelyDDAVP (deamino 8 D-arginine vasopressin)Use commercial nasal drops1-4 ug/kg SC 30 minutes prior to surgeryDuration 2 hoursWorks best for Type 1Desmopressin acetate for injectionSame protocolThyroxine – no longer recommendedSlide13

von Willebrand DiseaseFor active bleedingFresh whole blood if significant blood loss or anemiaFresh frozen plasma or cryoprecipitateSmaller volume prevents volume overloadGreatly reduces risk of transfusion reactionTransfusing RBC and von Willebrand Factor to support primary hemostasisPlatelet transfusion is difficult in practiceLifespan of transfused platelets is less than 24 hours in fresh whole bloodConsider when bleeding into the CNS or life threatening uncontrolled bleedingSlide14

von Willebrand DiseaseFor active bleedingStored whole blood and packed cells contain no appreciable active plateletsType 2 and 3 may need 2nd & 3rd transfusion over the next 24-48 hoursSurgery can decompensate any dog with subclinical coagulopathyUses up platelets, factors, in short supplySlide15

CryoprecipitatePreferred for vWDz, but very expensivePrepared from fresh frozen plasmaSupernatant is decanted off during a slow thawWhite precipitate forms during the thaw CPT high in Factor 8, 13, vWF and fibrinogenContains 5-10x concentration of vWF10% volume of FFP5% volume of whole bloodPreferred for

von Willebrand Disease

Hemophilia A (factor 8 deficiency)

Fibrinogen deficiency – cockers, Kerry BluesSlide16

Congenital ThrombocytopathiaTreat when bleeding from injury, or perioperativelyFresh whole blood transfusionPlatelet transfusionDraw immediately prior to transfusionStore at room temperature until administeredCitrate-based coagulantSlide17

Platelet Rich PlasmaCentrifuged with low G force within 6 hours of collection80% of the platelets are harvestedSuspended in 1/3 of whole blood volumeLow volume platelet concentrates prepared from PRP by a second centrifugation.Maintain at room temperature until transfused, as soon as possibleSlide18

HemophiliaOnly vitamin K dependent factor deficiency in Devon Rex is treatableRestrict activity to avoid traumaAvoid surgery, venipuncture, restraint, IM injections.Avoid medications that interfere with primary hemostasisNSAIDs, phenothiazinesTransfuse active bleeding or perioperativelyFresh whole blood if bleeding or anemic

Plasma if not bleeding or anemic

Cryoprecipitate preferred for vWDz, fibrinogen deficiency or hemophilia ASlide19

Vitamin K antagonismInduce vomiting if known ingestion within several hoursActivated charcoal and catharticInject vitamin K 2.5-5 mg/kgThen vitamin K 2.5 mg/kg/day POMinimum 2 weeksContinue until 2 weeks past normal PTRecheck PT 2 days after stopping vitamin KIf elevated again, 2 more weeks vitamin KSlide20

Vitamin K antagonismIdentify and treat gall bladder, intestinal or nutritional disease that may be contributingAvoid drugs that inhibit enzyme that activates vitamin K dependent factorsVitamin K epoxide reductaseSulfonamides and cephalosporinsAvoid drugs that decrease protein binding of toxinsSulfonamides

Corticosteroids

Phenylbutazone

Avoid drugs that cause thrombocytopenia, thrombocytopathia, etc.Slide21

Treating Liver Failure CoagulopathyReplace coagulation factorsPlasma 3-5 ml/kg up to every 8 hoursTransfuse prior to surgeryUsed to incubate with heparin 30 minutes to transfusion, to activate AT350 U/kg added to plasma transfusionOr fresh whole blood if anemic or actively bleedingVitamin K 2.5 mg/kg/day as long if PT prolongedSlide22

Snake Bite CoagulopathySupportive treatment for snake bite toxicityAntivenin accelerates resolution of thrombocytopeniaMust be given within 24 hours of envenomationWithin 4 hours for maximum effectAntivenin will not affect tissue necrosis2 kinds of antiveninACP – contains entire equine IgG to venomNot effective against Mojave rattlersHalf life 60-200 hours

1-5 vials IV, give subsequent vials every 2 hours

Measure circumference every 15-30 minutes

Continue antivenin until swelling slows or stopsSlide23

Snake Bite CoagulopathyFab – contains fragment of ovine IgG to venom5x more effectiveEffective against Mohave rattler and othersmust repeat every 18 hoursLess likely to cause anaphylaxis or serum sicknessPremedicate with diphenhydramineSkin testing prior to IV administration is controversial – many false positives and negativesThrombocytopenia often resolves within 72 hours

Heparin and blood products are not likely to helpSlide24

Snake Bite CoagulopathySerial coags are important because coagulopathy can be delayedSerum sickness can occur in 3 days to 3 weeks (immune complex disease)Fever, joint pain, myalgia, edema, etc.Slide25

ThromboembolismReduce thrombogenesisHeparin (UF) 200 U/kg SC TIDProlong PTT to 1.5 x normalDalteparin (Fragmin© - LMW heparin)Dogs 150 U/kg SC TIDCats 180 U/kg q4-6 hrsEnoxaparin (Lovenox© - LMW heparin)Dogs 0.8-1 mg/kg TID-QIDCats 1.25 mg/kg q TIDLWMH Monitoring - anti-xA activity at Cornell

Many argue that heparin therapy helps little if AT3 is low – must give plasma concurrentlySlide26

ThromboembolismReduce thrombogenesisAntiplatelet drugsAspirinCats 5-25 mg/kg PO twice a weekSome use dose as low as 5 mg/catDogs 0.5 mg/kg PO BIDClopidogrel (Plavix©)Cats 18.75 mg (1/4 tablet) per cat PO SIDCoumadin – not used much any moreMonitor INR (international Normalization Ratio)

Calculate using PTT and coefficients from your lab

Plasma 3-5 ml/kg PRN q8hrsSlide27

ThromboembolismThrombolytic therapyRisk of reperfusion injury (which can be fatal) is highRisk also of smaller emboli causing more problems further downstreamtPA, streptokinase and urokinase are used24-hour monitoring is required to use thrombolyticsSlide28

Treating DICTreat the underlying causeIf cause is untreatable, prognosis is dismalEnsure adequate tissue perfusion despite widespread thrombosisReplace consumed blood componentsAnticoagulant therapyHeparin (UF) 50 U/kg SC TID if no gross thrombosis200 U/kg SC TID if apparent thrombosisDalteparin, EnoxaparinSlide29

AcknowledgementsChapter 2: The Complete Blood Count, Bone Marrow Examination, and Blood BankingDouglass Weiss and Harold TvedtenSmall Animal Clinical Diagnosis by Laboratory Methods, eds Michael D Willard and Harold Tvedten, 5th Ed 2012

Chapter

5: Hemostatic Abnormalities

Harold

Tvedten

Small Animal Clinical Diagnosis by Laboratory Methods, eds Michael D Willard and Harold Tvedten, 5

th

Ed 2012Slide30

AcknowledgementsChapter 63: Bleeding Disorders: Epistaxis and HemoptysisTracy GiegerTextbook of Veterinary Internal Medicine, eds Stephen J Ettinger and Edward C Feldman, 6th

Ed 2005

Chapter

64: Petechiae and Ecchymoses

Mary Beth Callan

Textbook of Veterinary Internal Medicine, eds Stephen J Ettinger and Edward C Feldman, 6

th

Ed 2005