inherited blood disorders Flashcards
what is an inherited bleeding disorder?
an acquired defect which affects the coagulation of the blood
what can inherited bleeding disorders affect?
coagulation cascade -reduction in coagulation factors/control problems platelets -number/function a combined deficiency
what is haemophilia?
too little clot formed
what is thrombophilia?
too much clot formed
what disorders reduce coagulation factors?
factor VII deficiency -haemophilia/haemophilia A factor IX deficiency -xmas disease/haemophilia B von Willlebrand's disease -reduced factor VIII level -reduced platelet aggregation factor XI deficiency
describe the inheritance of haemophilia A & B
sex-linked recessive
defective gene on the X chromosome
males affected
females carrier
what does the severity of haemophilia A & B depend on?
amount of factor produced, 1iu is normal severe <0.01iu moderate -0.02-0.09iu mild 0.1-0.4iu carrier <0.5iu
how is mild and carrier haemophilia A managed?
DDAVP
very mild only require oral tranexamic acid
how is severe and moderate haemophilia A managed?
recombinant factor VII
-produced in lab
what is DDAVP
releases factor VIII that has been bound to endothelial cells giving temporary boost to factor level and clotting ability
what is tranexamic acid?
inhibitor of fibrinolysis-keeps any clot formed
how is mild and carrier haemophilia B managed?
recombinant factor IX
how is severe and moderate haemophilia B managed?
recombinant factor IX
what are coagulation factor inhibitors?
antibodies which develop factor VIII & IX
describe the reaction to coagulation factor inhibitors
amount of antibody developed varies between px
high levels more frequent factors given
peak then settles
2nd dose larger to overcome inhibitors produced in first dose
some develop inhibitor when first start tx
describe von Willebrand’s disease
autosomal dominant (not X chromosome) both sexes equal deficiency in von willebrands factor reduction in factor VIIi levels defective vW factor on platelets interacts badly with factor VIII so poor clot activation by platelets
what are the types of von Willebrand’s?
1- dominant mild
2- dominant mild
3- recessive severe
how is severe von Willebrand’s treated
DDAVP
how is mild and carrier von Willebrand’s treated?
oral tranexamic acid
how do rarer bleeding disorders occur?
inherited defects of other factors in the coagulation pathway
inherited defect of either the number or function of the platalets
how should you manage dental px with bleeding disorders?
vary depending on likelihood of bleeding
-non-bleeding procedures in primary care
bleeding risk depends on baseline factor activity
-higher=lower risk
how is dental care given to mild/carrier hameophiliacs?
shared by GDP/PDS depending on procedure/LA needs
px reviewed at haemophilia centre dental unit every 2 years
how is dental care given to severe/moderate haemophiliacs
dental unit in haemophilia centre
no-risk treatments in primary care
what are bleeding risk procedures?
LA extractions minor oral surgery perio surgery biopsies
what LA is safe?
buccal infiltration
intraligamentary
intra-papillary
what are dangerous LA?
IDB
lingual infiltration
posterior superior nerve block
how should severe/moderate px be observed after extraction/surgery?
overnight
how should mild/carrier px be observed after extraction/surgery?
for 2-3 hours
how is prevention given?
dietary advice oral hygiene fluoride supplements regular dental care fissure sealant- even adult
what is thrombophilia?
increased risk of clots forming
-formation greater than breakdown ability
-formed inappropriately in circulation
often acquired with genetic tendency
if clot emobilises can become major blockage
describe inherited hypercoagulation
protein C deficiency
protein s deficiency
factor V leiden
antithromib III deficiency
describe acquired hypercoagulation
antiphospholipid syndrome oral contraceptives surgery trauma cancer pregnancy immobilisation
what is thrombocytopenia?
reduced platelet numbers
what are qualitative disorders?
normal platelet number but abnormal function
what is thrombocythemia?
increased platelet numbers
what can cause thrombocytopenia?
idiopathic drug related -alcohol -penicillin based drugs -heparin secondary to lymphoproliferative disorder eg leukemia
when can dental tx safely proceed in thrombocytopenia?
100x10^9 primary care
50x10^9 hospital
how can qualitative platelet disorders be acquired?
cirrhosis
drugs
alcohol
cardiopulmonary bypass
what causes inherited qualitative platelet disorders?
bernard soulier syndrome
hermansky pudlak
glanzmann’s thrombasthenia
what are safe procedures for pz with platelet disorders?
hygiene therapy removable pros rest. dentistry endodontics ortho only when platelet count > 100x10^9/L
what procedures is special care required for platelet disorder px?
extractions
minor oral surgery
perio surgery
biopsies
describe the platelet count for each dental care setting for px with platelet disorders
below 100x10^9 primary care
below 50x10^9 hospital
above500x10^9 either
