4. Definition
• It is an inherited bleeding disorder that is
caused by the lack or defective protein that is
needed for blood to clot.
5. Haemophilia A and B
• Both types of
haemophilia have the
same clinical features and
inheritance pattern.
• Only blood tests can
differentiate them.
• Knowing which factor is
defective helps to give
correct treatment.
6. Hemophilia A
• It is an X-linked inherited bleeding disorder
caused by the mutations of factor VIII gene on
X chromosome which leads to development of
variable hemorrhages into the joints, muscles
and prolonged bleeding from wounds.
7. Biochemistry
• Factor VIII complex has two components:
–Factor VIII C
–Factor VIII R (the von Willebrand factor –
vWf)
• von Willebrand factor in the presence of
injured endothelium attracts platelets to the
injured area for clotting cascade to ensue.
8. Genetics
• Female Carriers have a 50% chance of
transmitting the F8 mutation.
• Daughters who inherit the mutation become
carriers as the other chromosone X is intact.
• Affected males transmit the mutation to all of
their daughters and none of their sons.
• Hemostasis requires more than 30% of normal
factors ie 8 and 9.
11. Father with Haemophilia
•Genetic defect causing
haemophilia is on X
chromosome not on Y
chromosone
•Daughter of
haemophiliac will inherit
his X and be carrier.
•Sons of a haemophiliac
will not be affected as
they inherit fathers Y
chromosome.
12. Carrier Mother
•Chances of a carrier mother
passing defective gene to a
child are 50:50.
•Each daughter has 50:50
chance being a carrier
•Each son has 50:50 chance of
having haemophilia.
13. Spontaneous Mutation
In some 30%
cases of
haemophilia
there is no
known
family
history
Haemophilia
is probably
the result of
spontaneous
genetic
mutation in
these families.
14. Normal Clotting
• Response to vessel injury
• Vasoconstriction to reduce blood flow
• Platelet plug formation (von Willebrand
factor binds damaged vessel and platelets)
• Activation of clotting cascade with generation
of fibrin clot formation
• Fibrinolysis (clot breakdown)
15. Coagulation
• The transformation of
liquid blood into a solid
gel
• Stops blood flow in the
damaged area
• Fibrin is the final protein
which produces a
meshwork to trap RBC
and other cells
16. Clinical features
• The most affected parts of the body are the
joints causing swelling, pain, decreased
function, and degenerative arthritis.
• Bleeding from wounds.
• Muscle hemorrhage can occur leading to
necrosis.
• Hematuria.
• Bleeding from tongue or lip.
21. Hemophilia B
• Is also known as Christmas disease.
• Is also inherited blood clotting disease which is
caused by a deficiency of a blood plasma protein
called factor IX.
• Because of the lack of factor IX blood gets into the
joints and may leave people disabled.
• Hemophilia A is seven times more common than
hemophilia B.
23. Prevention and How Bleeding Can
Treatment.
• Prevention for hemophilia B is also the same
as hemophilia A.
• R = rest.
• I = ice.
• C = compression.
• E = elevation.
29. Platelets
• Thrombocytes are fragments of
megakaryocytes
• Thrombopoietin (produced in liver, bone
marrow and kidney) stimulates platelet
production.
• Their life span is 5-9 days.
• They play an important role in tissue healing
and clot formation.
33. Sources of vitamin K
• Green leafy vegetables
• Vegetable oil
• Cereals
http://health.allrefer.com/health/nutrition.html
34. Functions of Vitamin K
• Coenzyme for the synthesis of
prothrombin and other blood clotting
factors in the liver
– Synthesis of clotting factors: II, VII, IX, X
– Mature prothrombin and clotting factors.
35. Other Terms
• Factor II (prothrombin)
• Factor VII (proconvertin)
• Factor IX (thromboplastin component)
• Factor X (Stuart factor)
36. Note
• Anticoagulant drugs, warfarin, inhibit the
activation of vitamin K.
• Blood coagulation time increases upon
injury.
37. Aetiology
• Deficiency is caused by fat malabsorption or
by the liver failure.
Infants: Hemorrhagic disease of the newborn
Decrease factors II, VII, IX, X
Human milk can’t provide enough vitamin K
Supplements are given by injection
38. Clinical Features
• Hemorrhagic disease of the newborn
• Bruising tendency, ecchymotic patches
(bleeding underneath the skin)
• Mucus membrane hemorrhage
• Post-traumatic bleeding / internal bleeding
• Prolonged prothrombin time
