L9: Bleeding and coagulation disorders Flashcards
primary phase of hemostasis :
vasoconstriction
-platelet plug formation
secondary phase of hemostasis :
deposition of fibrin mesh
characteristics of vascular/ platelet bleeding :
-easy bruising / spontaneous bleeding from small vessels
-bleeding into skin and mucous membrane especially in mouth and nose
characteristics of coagulation disorders :
-typically associated with hemarthroses , muscle hematomas
-bleeding after injury or surgery following a short delay
normal platelet count :
150,000-450,000
(150-450x10^9/l)
normal bleeding time :
3-10 minutes
-prolonged in thrombocytopenia , platelet functional disorders , von will brands disease
bleeding time is prolonged in the following conditions :
-thrombocytopenia
-platelet functional disorders
-von will brands disease
clotting time in all coagulation disorders is prolonged
normal prothrombin time :
12-15 seconds
prothrombin time is prolonged in :
abnormalities of extrinsic system :
- factors I,II,V,VII,X
-liver disease
-patient taking warfarin
which test assesses the function of intrinsic system?
activated partial thromboplastin:
Factors I,II,V,VIII,IX,X,XI,XII
-It is prolonged if any of those factors are deficient (heparin therapy)
normal thrombin time and when is it prolonged:
12 seconds
-prolonged in fibrinogen deficiency , dysfibrinogenemia , and heparin therapy
correction tests are used for:
differentiating between deficiency of clotting factors and inhibitors of coagulation
factor assays are used to:
confirm coagulation defects caused by inherited deficiency of single coagulation factor
congenital vessel wall abnormalities :
-osler-weber-rendu syndrome (hereditary hemorrhagic telangiectasia
-Ehlers-danlos syndrome (connective tissue disorder
acquired vessel wall abnormalities :
septicemia(meningococcal infection)
-vasculitis ( henoch-schonlein purpura , senile purpura)
-scurvy
-drug use (steroids)
platelet count at
50-100:
20-50:
<20:
-moderate bleeding after injury
-purpura may occur+ hemorrhage after injury
-purpura is common+ spontaneous hemorrhage from mucous membranes + risk of intra-cranial hemorrhage
impaired production of platelets occurs due to:
-bone marrow failure
-infiltration (leukemias , myelofibrosis , carcinoma )
-megaloblastic anemia
excessive destruction of platelets is due to :
-idiopathic thrombocytopenic purpura
-connective tissue disease(SLE)
-drugs like heparin
excessive consumption (DIC)
idiopathic thrombocytopenic purpura :
immune destruction of platelets–
autoantibodies directed against GP IIb and IIIa
premature removal of platelets by monocytes
-
difference between idiopathic purpura in children and in adults
:
children :
-acute
-self limiting
-following viral infection
-immunization
adults:
-insidious onset
-chronic course with remissions and relapse
-associated with auto-immune disorders.
idiopathic purpura treatment :
-prednisolone
-platelet transfusion
-intravenous immunoglobulin
second line:
-increased dose of steroids
-spleenectomy
platelet function disorders :(deficiency in what ?)
-glanzmann’s thromboasthenis :
-berrard-soulier syndrome
-storage pool disease :
-G: IIb , IIIa ( same GP AFFECTED IN idiopathic purpura)
-B: IIb
-Storage: lack of dense bodies
examples of acquired platelet function disorders
-myeloproliferative disorders
-renal failure
-chronic liver disease
-paraproteinemias
-drug induces: asprin and NSAIDs
which drugs can cause acquired platelet function disorders ?
NSAIDs , aspirn
inherited and acquired coagulation disorders of secondary haemostasis :
-involvw deficiency of a single factor :
-Hemophilia A,B
-von Willebrand’s disease
acquired:
-more frequent
-deficiency of several factors
ex: disseminated intravascular coagulation , liver disease, renal failure , vitamin K deficiency
sequelae of hemophilia :
-chronic hemophilic arthropathy
-fibrosis
-muscle shortening
-tendon nerve compression by hematoma
hemophillia diagnosis
BT:
CT:
PT:
APTT:
Bleeding time is normal
clotting time is prolonged
prothrombin time is normal
Activated partial TT is prolonged
hemophilia B is caused by deficiency of :
factor IX
-CHRISTMAS DISEASE
function of vW factor :
-acts as a carrier protein for factor VIII
- helps platelets adhere to sub-endothelial structures
gene for it is located on chromosome 12
lab diagnosis for von willibrands disease :
BT:
PT:
APTT:
bleeding time is prolonged
prothrombin time is normal
APPTT: prolonged
which clotting factor is reduced in patients suffering from vW syndrome ?
factor VIII
Causes of disseminated intra vascular coagulation :
-septicemia , meningococcal infection , falciparum malaria
-malignancies
-obstetric causes
-snake bite
=varies from bleeding to profound hemostatic failure with wide spread hemorrhages (PT , APTT,TT prolonged)
how can liver disease affect platelet count?
-thrombocytopenia from hypersplenism
-can also affect functionality of platelets
bleeding manifestations of renal failure are of
____ type
platelet
what are the vitamin K dependant factors ?
II , V , XII, IX,X protein C and S
Causes of vitamin K deficiency
-Inadequate stores as in the new born
Hemorrhagic disease of the new born
- Severe malnutrition
- Malabsorption of Vit K as in cholestatic Jaundice
- Oral anticoagulants
