Haematology: Haemophila A and B Flashcards
Are they the most common severe inherited coagulation disorders?
Yes
What is the inheritance pattern of both?
X linked recessive, so only affects males
Females = homozygous
What is there a deficiency of in haemophilia A?
Factor VIII
What does haemophilia B have a deficiency of?
Factor IX
People with haemophilia have normal platelets, but impaired clotting, so they cannot produce adequate amounts of…
Fibrin
Is haemophilia A or B more common?
A
2/3 have a FH of haemophilia and in 1/3 it is…
Sporadic
How is the disorder graded?
Severe (spontaneous joint/muscle bleeds)
Moderate (bleed after minor trauma)
Mild (bleed after surgery)
Depends on the factor VIII or factor IX level
How do patients present?
Easy bruising
Massive haemorrhage after trauma and surgery
“Spontaneous” haemorrhages occur in areas subject to minor trauma e.g joints
Recurrent bleeding into joints leads to deformity
What is bleeding into joints called?
Haemarthrosis
Why are petichiae not seen?
They are caused by blood leaking from capillaries - typically due to vasculitis or abnormalities in number or function of platelets
When do most children present?
Towards end of first year of life when they start crawling or walking
Bleeding episodes are most frequently in…
Joints and muscles
What percentage present in neonatal period and how?
40%
Particularly with intracranial haemorrhage, bleeding post circumcision or prolonged oozing from heel prick and venepuncture sites
Describe the investigation results
Normal platelet count
Normal PT
Prolonged APTT
Low factor VIII or IX assay
