Blood Coagulatio n
Hemostasis:BV Injury
PlateletActivation
Plt-Fusion
Blood Vessel Constriction
CoagulationActivation
Stable Hemostatic Plug
Thromibn,
Fibrin
Reduced
Blood flow
Tissue Factor
Primary hemostatic plug
Neural
Coagulation:
Intrinsic 12,11,9,8 (aPTT-)
Extrinsic-7(PT)
Prothrombin Thrombin
Fibrinogen Fibrin
Common Path (TT)FX FXa
Clot formation & retraction
Fibrinogen
Fibrin Mononer
Fibrin Polymer
Cross LinkedFibrin
Thrombin
F-XIIIa
ProcoagulantPlateletsFactorsFibrinogenvon Willebrand Factor
AnticoagulantAntithrombin IIIProtein CProtein S
ProfibrinolyticPlasminogentPAFibrin Fragment D-dimer
AntifibrinolyticPAI-1Alpha-2 Antiplasmin
clotclot RESOLUTIONFORMATION
Coagulation Made Easy- The Mixing Study
• Useful to differentiate etiologies of prolonged clotting in a coagulation assay.
• Patient’s plasma is mixed 50:50 with normal plasma. Coagulation assay is repeated.
• If “substantial” correction is noted after mix, suspect clotting factor deficiency.
• If no or minimal correction seen, suspect inhibitor.
Disorders of the haemostatic mechanism are devided into three main groups:
• Disorders of the vessels• Disorders of the platelets
• Disorders of the coagulation mechanism („coagulopathies”)
„ purpuric diseases”
The investigation of a patient with a suspected disorder of haemostasis
– case history (personal details, family history)
– inspection (type of bleeding)– physical examination– other known diseases– drugs and medications– laboratory tests
Certain signs and symptoms are virtually diagnostic of disordered haemostasis.
The main symptom of all diseases is the bleeding:
● in the „purpuric disorders” cutaneous and mucosal bleeding usually is prominent
● in different types of „coagulopathies” hemarthroses, haematomas are the characteristic bleeding manifestations.
The onset of bleeding following trauma frequently is delayed (recur in a matter of hours) (the temporary hemostatic adequacy of the platelet plug may explain this phenomenon).
Petechiae, purpuras: small capillary haemorrhages ranging from the size of a pinhead to much larger
Haematomas: may be spontaneous (in a serious hemorrhagic disease) or may occur after trauma (in a mild hemorrhagic disease).
Intramuscular injection may be very dangerous to the patient with a bleeding disorder
Venipuncture (if skilfully performed) is without danger becouse the elasticity of the venous walls.
Coagulopathies
• Aquired: generally several coagulation abnormalities are present. Clinical picture is complicated by signs and symptoms of the underlying disease.
Deficiencies of the vitamin K dependent coagulation factors (FII, VII, IX, X) Hepatic disorders Accelerated destruction of blood coagulation (DIC) Inhibitors of coagulation Others (massive transfusion, extracorporal circulation)
• Hereditary: deficiency or abnormality of a single coagulation factor.
– Hemofilia A (FVIII)– Hemofilia B (FIX)– Von Willebrand’s disease– Rare coagulopathies
(FI. II. V. VII. X. XI. XIII)
Hereditary Factor DeficienciesHemophilia
• x-linked recessive conditions (males only)
• type A : F VIII:C deficiency (Classical Hemophilia)
B : F IX deficiency (Christmas disease)
C : F XI deficiency
• unexplained bruising or bleeding in young males,
usually ~ 1 yr of age
• joint & muscle bleeding → arthropathy
HaemophiliaA bleeding disorder in which clotting factor VIII (eight) /Haemophilia A/ or IX (nine) /Haemophilia B/ in a person's blood plasma is missing or is at a low level.
Prevalence:haemophilia A: 105/million menhaemophilia B: 28/million men
• In haemophilia, VIII or IX clotting factor is missing, or the level of that factor is low.
• This makes it difficult for the blood to form a clot, so bleeding continues longer than usual.
The hemophilia gene is carried on the X chromosome in males who lack a normal allele, the defect is manifested by clinical haemophilia. Women may be carriers.
Haemophilia is a lifelong disease
• A person born with haemophilia will have it for life.
• The level of factor VIII or IX in his blood usually stays the same throughout his life.
Hereditary Factor DeficienciesHemophilia
■ screening: prolonged PTT■ hemophilia A
mild
moderate
severe : life-threatening (CNS bleed)
• treatment
factor replacement
rFVIIa
Factor VIII Concentrate Necessary for Hemostasis
Factor VIII Concentrate
(% of normal)
Spontaneous hemorrhage 1-3 %
Moderate trauma 4-8 %
Hemarthrosis/deep skeletal
muscle hemorrhage
10-15 %
Major surgery > 30%
Hemophilia B(Christmas disease, Factor IX def.)
•less common than hemophilia A•similar clinical Sx and inheritance pattern as hemophilia A (sex-linked)
II
XII
XI
IX
VIII VII
X
V
I
XIII
Stable clot
von Willebrand’s disease• easy bruisability (no bleeding
into joints)• unable to release VIII-vWF• intact VIII-vWF synthesis• VIII-C level is also decreased
(unknown reason)• autosomal dominant
• 1 in 30,000 population• usually diagnosed in childhood
or young adults• increased bleeding time• normal plt, PT• normal or increased aPTT
Hereditary Platelet Disordervon Willebrand Disease (vWD)
• most common congenital bleeding disorder
• quantitative or qualitative abn. of vWF
• Type 1: most common form
• partial quantitative deficiency of vWF
• autosomal dominant
• mucocutaneous bleeding
• hematology consult prior to surgery
• prolonged bleeding time, normal platelet
Hereditary Platelet Disordersvon Willebrand Disease (vWD)
Type 2: qualitative alterations in the vWF structure
& function
Type 3: least common and most severe
• Complete absence of vWF in plasma or storage organelle
• Autosomal recessive
• acquired vWD• Lymphoproliferative disease ▪ cardiac/valvular disease
• Tumors ▪ medications (valproic acid)
• Autoimmune disease ▪ hypothyroidism
Hereditary Platelet Disordersvon Willebrand Disease
• Treatment: Desmopressin (DDAVP)
• synthetic analog of vasopressin
• ↑ both F VIII and vWF 3 - 5x in 30 mins
• preop prophylactic dose: 0.3 mcg/kg IV in 50 -100
ml NS infused 30-60 mins q 12-24 hrs PRN
• duration 8-10 hrs
• intranasal dose: 300 mcg – for home treatment,
not for preop prophylaxis
Hereditary Bleeding Disordersvon Willebrand Disease
• DDAVP
• vasomotor effect: flushing, ↑HR, headache
• SE: hyponatremia, seizures
• not for children < 3 yrs old
• unresponsive to DDAVP (15%)
• cryoprecipitate
• FFP
• factor VIII / vWF concentrate
Vitamin K Deficiency
vitamin K dependent factors : II, VII, IX, X
•acquired disorder•may occur in malnutrition, malabsorption, biliary obstruction, drug
•increased PT•normal bleeding time, plt•normal or increased aPTT
II
XII
XI
IX
VIII VII
X
V
I
XIII
Stable clot
Severe Liver Disease
factors synthesized in liver : II, V, VII, IX, X, fibrinogen
• increased PT, aPTT• normal bleeding time, plt
II
XII
XI
IX
VIII VII
X
V
I
XIII
Stable clot
Platelet Dysfunction, Factor Deficiencies & Presence of Inhibitors
• Liver disease
• synthesis of coagulation factors (except VIII),
anticoagulants, ATIII, protein C & S, plasminogen
• clearance of activated clotting factors, tPA, FDPs
• DIC
Blood Component TherapyTransfusion of FFP
1) replacement of isolated factor deficiency
2) reversal of coumadin
3) antitrombin III deficiency
4) treatment of immunodeficiencies
5) treatment of TTP
6) massive blood transfusion
Blood Component TherapyCryoprecipitate
• contains significant levels of factor VIIIC,
factor VIII: vwF, XIII, fibrinogen
• indications:
1) hemophilia
2) von Willebrand disease
3) fibrinogen deficiencies
4) uremic platelet dysfunction
Disseminated Intravascular Coagulation (DIC)
- an acute, subacute, or chronic thrombohemorrhagic disorder occurring as a secondary complication in a variety of diseases
- activation of clotting system resulting in wide spread formation of microthrombi throughout the microcirculation
- as a consequence, causing consumption of platelets, fibrin and coagulation factors, and activation of thrombolytic mechanism
Two major triggering mechanisms1. release of tissue factor or thromboplastic substance2. widespread endothelial injury
DICTriggering Mechanisms
1. release of tissue factor or thromboplastic substance- placental tissue- granules from leukemic cells- bacterial endotoxin- mucus from adeno CA
2. widespread endothelial injury- Ag-Ab immune complex deposit- extreme temperature- microorganisms
DICPathology: - wide spread thrombi
(brain, heart, lungs, kidneys, adrenals, spleen , liver)- microinfarcts
Clinical: - ~50% associated with obstetric complications- ~30% with carcinomatosis
- microangiopathic anemia- dyspnea, cyanosis- convulsions, coma- oliguria, acute renal failure- shock, circulatory failure