Week 9 Flashcards
What is the clinical presentation of bleeding
Site
Onset
Presentation
Site
Localized - one site (trauma or acute injury)
Generalized- more than one site (defect in primary or secondary hemostatsis)
Onset
Right after trauma
delayed or recurring
spontaneous
Presentation
Mucocutaneous - skin and mucous membranes
Anatomic - deeper tissue involvement
When you look at patient history what is looked at
Account of bleeding episode
-onset, location, pattern, duration and severity
history of bleeding
-after surgery, pregnancy, diabetes, transfusions, anemia
family history
age and gender
diet and medication history
Generalized Mucocutaneous presentation:
petechiae
purpura
ecchymosis - bruising
-if there is more then one unprovoked hemorrhagic lesion it indicates primary hemostasis disorder
-associated with :
vascular disorders
thrombocytopenia
qualitative platelet disorders
vWD
Petechiae - Pinpoint hemorrhages in skin 1mm dia
Purpura - Hemorrhages greater than 3mm in diameter, caused by extravasated (seeping) red blood cells
Ecchymosis (Bruising) - Hemorrhages greater than 1cm with irregular shapes, seen after trauma
Anatomic (soft tissue) presentation:
-acquired or congential defects in secondary hemostatis
-uncontrolled fibrinolysis, presence of factor inhibitors, factor deficiencies
-recurrent or excessive bleeding after minor trauma
-bleeding can be spontaneous
-bleeding mostly internal joints (hemathroses), body cavities, muscles, CNS
what can defects in 2ndary hemostasis result from
Decreased or abnormal synthesis of factors
-Acquired coagulopathy - Disease state
-Congenital coagulopathy - Loss or mutation of gene
Loss or consumption of factors
-Acquired - Initiation of coagulation
Production of abnormal interfering substances
-Inhibitors (antibodies) that interfere with coagulation pathways
What are some indications for congenital disorders
-family history of bleeding
-excessive bleeding from umbilical cord
-repeated hemorrhages in childhood/adulthood
-chronic petechaiae, purpura
-bleeding into joints, CNS or soft tissues
Congenital Deficiencies how are they caused and where are they seen
-single factor deficiency - spontaneous or inherited gene mutation coding for factor
-can be multiple factor deficiencies or platelet def
-can be in all pathways
-common are vwd, hemo A (fviii def) and Hem B (FIX def), PLT disorders
-in rare instances
-inherited fib, prothom,
severe factor def - uncommon and found in young children
mild congenital deficiencies - asymp, until pt reaches adulthood or has physical challenges like dental procedure
Von Willebrand Disease (VWD)
VWF & FVIII
-most prevalent congenital mucocutaneous bleeding disorder
-autosomal dominant or recessive inheritance -equally in men and women
-caused VWF germline mutations producing quantitative VWF (Type 1 and 3 VWD) or qualitative VWF - type 2 VWD
What is VWF
-plasma procoagulant and acute phase reactant
-LARGE multimeric glycoprotein
-circulates in low concentrations in plasma
-produced by megakaryocytes and ECs
-stored in alpha granules of PLTs and endothelial cells Weibel-Palade bodies
-released due to BV injury
-can fluctuate given a persons blood type, inflammation, hormones, physical stress
-increased in 2nd and 3rd trimester of pregnancy due to increase in estrogen. The decrease after delivery causes acute post partum hemorrhage
-monomer with 4 binding sites:
Platelet glycoprotein Ib/IX/V receptor
Platelet glycoprotein IIb/IIIa receptor
Collagen binding site
Factor VIII binding site
What role does VWF play in hemostasis
-binds exposed subendothelial collagen during trauma of vasculature
-platelets attach to vwf with GPIb/IX/V receptor
-VWF:GPIb/IX/V activates platelets to express a second VWF binding site, GPIIb/IIIa
-GPIIb/IIIa binds VWF and fibrinogen to mediate irreversible platelet-to-platelet aggregation
-VWF carrier protein of FVIII
What is the function of VWF
-initiate primary hemostatis by bridging PLTs and subendothelial collagen
-supports PLT aggregation with receptor site
-transports FVIII in blood increasing half life by protecting it from proteolysis in plasma.
-carrier molecule role in 2ndary hemostasis
-regulated by ADAM13- enzyme that prevents unnecessary clotting
-abnormalities lead to severe bleeding
When doing VWF testing why do a cbc and pt/aptt
CBC
-rule out thrombocytopenia as cause of bleeding
-can be normal or decreased because of subtype
PT and APTT
-to rule out coag factor deficiencies other than VWF def
-APTT can be normal or prolonged depending of FVIII plasma concentration
Subtype Classifications are determined in lab for VWF testing
Plasma concentration
-VWF:AG ratio QUANTITATIVE immunoassay
VWF activity by RCOF assay
-QUALITATIVE look at VWF function with VWF:RCo assay
FVIII activity assay (FVIII:C)
-when FVIII are less than 30% of normal then anatomic soft tissue bleeding accompanies the mucocutaneous bleeding pattern of VWD
Von Willebrand Disease
(VWD)
Pathophysiology
-Quantitative VWF abnormality = reduced plasma concentration of VWF and FVIII
-Qualitative VWF abnormality = VWF function reduced (affecting PLT adhesion and aggregation)
-pts with decreased plt adhesion or mucosal/mucocutaneous bleeding -epitaxis, ecchymosis is impaired primary hemostasis
-Quantitaive VWF def can also create FVIII deficiency that can lead to impaired secondary hemostasis with possible anatomic bleeding
there are 3 types
Type 2 has 2A, 2B, 2M, 2N -autosomal hemophilia
What is the Ristocetin Cofactor Assay
VWF:RCo (qualitative) analysis
-platelet aggregation test with pt PPP with reagent platelets and ristocetin
-PLT aggregation due to Ristocetin only happens in VWF presence
-if Ristocetin is added to pt plasma that doesnt have VWF then the reagent PLT will not clump
how to interpret VWD Laboratory Testing
-look at the ratio of activity to AG concentration
VWF:RCo : VWF:Ag
-errors in quantification vs errors in VWF function
-Qualitative VWD is suggested when ratio of Ristocetin assay to the antigen concentration is <0.5 = Type 2 VWD
Subtypes are determined by
VWF Multimer Size patterns (P.A.G.E)
Polyacrylamide Gel Electrophoresis - separated by size not charge
-qualitative assay that looks at overall size distribution of VWF multimers
What is hemophilia A
-CLASSIC hemophilia
-single factor def and congenital
-FVIII deficiency slows coag pathway production of thrombin leading to bleeding
-FVIII protein translated from X chromosome. Deletions, stop codons and missense mutation cause the QAUNTITATIVE def in FVIII
-marked by anatomic soft tissue bleeding
APTT ALWAYS PROLONGED
-Normal plt aggregation
manifests as
-deep muscle hemorrhages
-hematomas
-wound oozing
-bleeding into CNS, peritoneum, GI tract
how are pt with HEMOPHILIA A treated
-DDAVP which helps to release VWF from storage to raise FVIII activity
-FVIII concentrate, “on demand” therapy
Recombinant FVIII concentrate (rFVIII) OR
Human plasma-derived FVIII (pdFVIII) - plasma donors
-CRYO - rare from plasma donors FVIII, VWF and FI
What is Hemophilia B
-Christmas disease
-single factor def and congenital- X linked
-marked by anatomic soft tissue bleeding - almost indistinguishable from Hemo A
-FIX def that reduces thrombin production
Patients are treated with:
Recombinant FIX concentrate
Gene therapy
What lab tests are done with PT with HEM A and B
-first the testing will have similar results
PT – Normal
APTT – Prolonged
Thrombin time – Normal
Fibrinogen assay – Normal
Corrected mixing studies
Factor assays – FVIII decreased (Hemophilia A)
Factor assays – FIX decreased (Hemophilia B)
What is hemophilia C
-Rosenthal syndrome
-FXI deficiency
-autosomal recessive
-severity of bleeding does not correlate to FXI assay
PT – Normal
APTT – Prolonged
Patients are treated with plasma infusions
What will we see in Other Congenital Single-Factor Deficiencies
-Rare autosomal recessive mutations associated with consanguinity
-Def in Fibrinogen, Prothrombin, FV, VII, X, or XIII. Use PT, APTT, TT to tell which factor def you have and THEN follow with factor specific assays
-causing anatomic hemorrhage
FVII deficiency
Inherited
Bleeding may not reflect FVII activity level
PT prolonged, APTT normal
Target of treatment is to obtain levels of 10-30%
FX deficiency
-Inherited or may be acquired – amyloidosis, paraproteinemia, or antifungal therapy
-Both PT and APTT prolonged
-Target of treatment is to obtain levels of 10-40%
FXIII deficiency
-rare
-happens in 3 forms all related to FXIII structure
-PT, APTT and TT – Normal
-pt can form weak clots (non cross linked) that dissolve
REMEMBER FXIII IS ALSO FIBRIN STABILIZING FACTOR
-do reflex testing - 5M Urea testing , FXIII quantitative
What is trauma induced coagulopathy - TIC
Acquired disorder
-fatal hemorrhage in trauma related deaths
-triggered by systemic shock
-leads to Coagulopathy and hemorrhage by ADAMS13 reduction, TF release, Coaf factor activation, hyperfibrinolysis and loss of coag control proteins
treatment:
Massive Transfusion (RBC Infusion) + Plasma (Thawed plasma or FP-24) + PLT concentrate (1:1:1- in equal amounts - approximating makeup of whole blood)
Liver disease - Acquired disease
- bleeding because of liver disease can be localized or generalized, mucocutaneous or anatomic
-Mucocutaneous bleeding - associated with thrombocytopenia and decreased platelet function
-Anatomic or soft tissue bleeding occurs because of procoagulant dysfunction and deficiency
-symptoms are jaundice and abdominal tenderness
Liver Disease – Procoagulant Factor Deficiency
-liver produces factors and coag regulatory proteins
-if hepatocytes are damaged then factors are decreased
-VWF is an exception – VWF is produced by megakaryocytes and endothelial cells
-FVIII also an exception – is also produced by vascular endothelial cells
-Vitamin K - dep factors also affected (FII, VII, IX, and X, and control proteins C, S, and Z)
-they are released without a 2nd carboxyl group and cannot participate in coag
-FVII affected first because it has the shorted half life
What would you see in liver disease lab results
PT, APTT, PLT , FIB
PT
-prolonged
-sensitive to FVII activity, it is a early marker for liver disease
APTT
-prolonged in severe disease
Plt count
-mild thrombocytopenia
Fib
-increased at first then reduced/abnormal later in disease as the disease severity increases
Liver Disease – Factor Deficiency or Dysfunction
Factor V
-Non-vitamin K-dependant, labile factor
-Reduced in liver disease (as well as FVII)
-Assessed by FV assay
-Not reduced in dietary Vitamin K deficiency
-Helps to differentiate the two diseases
Liver Disease – Factor Deficiency or Dysfunction
Fibrinogen
-Elevated in early liver disease - because is an APR
-Moderate or severe liver disease
-Dysfibrinogenemia occurs – fibrinogen is coated with sialic acid- leading to poor fibrinogen function and resulting in general anatomic bleeding
-Marked decrease in end-stage liver failure
-Fibrinogen levels severely decreased (hallmark)
Liver Disease - Non-Factor Issues
Platelet Abnormalities
Systemic Fibrinolysis
Platelet Abnormalities
-moderate thrombocytopenia because of shortened PLT survival, low production
-seen in reduced PLT aggregometry testing
-cause would be portal hypertension and hepatosplenomegaly
Systemic Fibrinolysis
-diseased liver does not clear circulating plasmin which is a fibrinolytic serine protease
Liver Disease – Treatment
Oral or IV Vitamin K therapy- short lived because liver metabolism is impaired
Transfusion of thawed Frozen Plasma, collected from normal donors - with ALL coaf factors
Cryoprecipitate in severe cases (Fibrinogen <0.5 g/L= bleeding is imminent) - VERY CONCENTRATED FIB
Liver transplant in severe cases of the disease
What is DIC
-uncontrolled hemostasis activation secondary to disease process
-causes both bleeding and clotting because platelets and coagulation factors are being used up at a fast rate
-CONSUMPTIVE COAGULOPATHY
-affects primary hemo (plt decrease), and 2ndary hemostasis (factor consumption = increase in PT APTT)
-causes clot formation in small vessels
-sets up systemic toxic and inflammatory processes that decrease flow to tissues, organs
-moderate to life threatening
-Acute is fatal and DIC can be chronic
What is a complication that can arise from liver disease
DIC
-low production of regulatory proteins (AT, Protein C and S)
-release of activated procoag from degenerating hepatocytes that cant be cleared by the liver
Disseminated Intravascular Coagulation (DIC)
Lab results and PBS MORPH
Lab results
-Platelet count decreased
-PT, APTT and TT are all prolonged
-Fibrinogen level may be decreased
-D-Dimer positive
PBS Morphology
-Intravascular fibrin production –
Microangiopathic hemolytic anemia (MAHA) - with thrombocytopenia and schistocytes
how do you treat DIC
Transfusion with :
Thawed frozen plasma: with ALL coag factors
Cryo - Concentrates FIB, FVII, VWF
Platelet or RBC transfusion
Heparin slows thrombotic process
Routine tests to monitor therapy
-PT, APTT, Fibrinogen, D-dimer, CBC (RBC Morph/PLT estimate), and Heparin assay
What is Renal disease
acquired disorder
-chronic renal failure associated with PLT dysfunction causing mucocutaneous bleeding
-altered plt function is the cause of bleeding
-adhesion and aggregation suppressed because of antiplatelet effects of compounds like guanidinosuccinic acid or Phenolic compounds coating PLT (PRIMARY affected)
-Thrombocytopenia & Anemia contribute to bleeding
-PT/APTT results are normal - -2º hemostasis typically unaffected
-Treatment - Dialysis, RBC transfusions, or EPO therapy
Vitamin K deficiency
acquired
how to solve
-found in food - leafy greans
-bowel flora produces Vit K
-needed daily body stores are limited
caused by :
-AB use
-malabsorption
-fad diets or IV nutrition
-hemorrhagic disease of the newborn , breastfeeding delays establishment of gut flora
-Coumadin overdose common in lab resulting in lack of function in VitK dep factors
results in
-mod to severe bleeding
-if Coumadin overdose - oral Vit K therapy 3 hours
-transfusion on frozen plasma
Vitamin K Deficiency Lab Results
factors affected:
Factors affected
II, VII, IX, X (& Protein C, S, and Z)
PT
PT is prolonged much before APTT
Due to short ½ life of FVII - first to decrease
APTT
APTT is eventually prolonged (deficiency must be severe before the APTT will be prolonged)
Fibrinogen
Fibrinogen levels are normal or slightly decreased
Autoanti-FVIII Inhibitor and Acquired Hemophilia
-acquired autoantibodies have been found in non hemo pt and can inhibit FII (prothrombin), V, VIII, IX, XIII, and VWF
-Autoantibodies against FVIII are most common
-autoanti-FVIII is diagnostic of acquired hemophilia, seen in pt over 60 with no underlying issues causing severe anatomic bleeding into soft tissue
-autoAB for other procoags are rare
Acquired hemophilia is occasionally associated with:
Rheumatoid arthritis (RA)
Inflammatory bowel disease
Systemic lupus erythematosus (SLE)
Lymphoproliferative disease
Pregnancy (acquired hemophilia triggered 2-5 months after delivery)
Clot-Based Assays to Detect Acquired Hemophilia
-if there is sudden hemorrhage that looks like acquired hemophilia - PT, APTT, and TT ordered
-If FVIII inhibitor present (most common inhibitor) -
PT and TT- normal (most likely)
APTT- prolonged
Reflex with Mixing Study and Factor/Inhibitor assay
FVIII assay - likely to show FVIII activity of 40% or less
Acquired von Willebrand Disease
-mod to severe mucocutaneous bleeding
-can be suspected in ANY pt with recent bleeding with no bleeding history
-Symptoms similar to congenital VWD
Bleeding caused by either:
Decreased VWF production
Adsorption of VWF to abnormal cell surfaces OR
Specific VWF Autoantibody
Can be associated with:
Hypothyroidism
Autoimmune disorders
Lymphoproliferative and Myeloproliferative disorders
Intestinal disorders
Congenital heart disease
Pesticide exposure
Uremia
Lab results
Acquired von Willebrand Disease
PT – Normal (not affected)
APTT - Prolonged (moderately)
- VWF available to support FVIII
As in congenital VWD, diagnosis based on VWF:RCo : VWF:AG ratio
-Diminished VWF activity and VWF antigen levels
Thrombotic Disorders
Antiphospholipid Antibodies APA
-autoantibody immunoglobulins that bind protein-phospholipid complexes (IgM or IgG isotypes)
Includes antibodies-
Lupus anticoagulant
Anticardiolipin
Anti-β2-GPI
Anti-DNA
-Non-specific inhibitors
-manifests are unexplained venous or arterial thrombosis, thrombocytopenia or recurrent fetal loss
Lupus Anticoagulant (LAC)
Antiphospholipid Antibody
-Most common APA
-found in 50% of pt with SLE (Systemic Lupus Erythematosus)
-antibodies promote abnormal clotting in vivo - THROMBOTIC
-Blocks or binds phospholipid in the PT/APTT reagent – preventing clotting in vitro (non-specific inhibitor)
Lab Investigation of Inhibitor - LAC
-APTT prolonged
-Mixing studies (APTT remains prolonged or Mix not corrected)
Lupus anticoagulant profile- Dilute Russell Viper Venom Test (DRVVT)
-most specific LAC assay
-based on ability of venom of Russell viper to induce thrombosis
-coag in venom activates FX which activates prothrombin to thrombin in presence of FV and phospholipid
-LAC AB interfere with clot promoting of phospholipid in vitro causing prolonged clotting time
Thrombotic Disorders associated with Fibrinogen Activity
Hypofibrinogenemia - FIB level less than 1 g/L
Afibrinogenemia - absence of fibrinogen
Dsyfibrinogenemia - presence of FIB that is biochemically abnormal and non-functional
Heparin-Induced Thrombocytopenia (HIT
-Consequence of immune response to UFH and LMWH
-Results in reduced PLT count via PLT activation, inflammation, and thrombosis
Laboratory Investigation of Bleeding
CBC
HGB, HCT, PLT count, and RET
-can show anemia from bleeding and BM response
-normal in inherited factor deficiencies
- abnormal in acquired disorders
-Depends on underlying cause of disorder
PT or APTT or both are prolonged
Thrombin time (qualitative analysis of FIB activity)
-If both PT & APTT are abnormal – common pathway?
-Start with Fibrinogen (FI) deficiency
Can be affected by inhibitors:
-Heparin, DTIs (sample contamination or therapy)
-Fibrinogen/fibrin degradation products
-Non-specific Inhibitors (LAC)
-Specific Factor Inhibitors/Antibodies
Fibrinogen assay (quantitative)
Platelet Function Tests - specific to confirm disease
Factor Assays - to determine what factor is deficient and % activity
Correction/Mixing Studies
-performed on plasma used to distinguish factor deficiencies from factor inhibitors
Differentiate between:
Factor deficiencies (single or multiple) OR
Specific Factor Antibodies or Inhibitors OR
Non-specific Antibodies or Inhibitors
-normal PT or APTT need 50% of normal levels in circulation
-mixing studies help to determine next steps to diagnose cause of abnormal PT and APTT
Reflex Tests for Factors
-When fibrinogen and an inhibitor have been ruled out, prolonged result(s) are the result of single factor OR multi-factor deficiency
-FACTOR ASSAYS determine which factor(s) are deficient
FVII and FVIII are most common
-Only PT or APTT Prolonged - specific assay
-Both PT & APTT Prolonged- factors from common pathway
What is the 5M urea solubility test
-assess FXIII deficiency or inhibition
-FXIII is insoluble in urea
-without FXIII, fibrin clot will dissolve rapidly in presence of urea
-Positive results should be confirmed by FXIII assay
Quantitative FXIII activity assay
-clots PPP with CaCL2
-visual inspection for clot at 1, 2, 3, 4, and 24 hours
clot at 24hrs = Normal FXIII levels
No clot at 24hrs = Abnormal FXIII levels
a decrease in clot size, fragmentation, cloudiness which is a FXIII abnormality
-abnormal at less than 2 %
