Haemophilia

Question 1

Definition

Answer 1

Bleeding diatheses resulting from an inherited deficiency of a clotting factor

Question 2

Subtypes

Answer 2

• Haemophilia A: MOST COMMON - deficiency in factor 8
• Haemophilia B: deficiency in factor 9
• Haemophilia C: RARE - deficiency in factor 11

Question 3

Aetiology

Answer 3

• Haemophilia A and B have X-linked recessive inheritance
• 30% of cases are new mutations
• Due to its inheritance pattern, Haemophilia is mainly seen in MALES

Question 4

Epidemiology

Answer 4

• Haemophilia A incidence: 1/10,000 males
• Haemophilia B incidence: 1/25,000 males
• Haemophilia C is more common in Ashkenazi Jews

Question 5

Presenting symptoms

Answer 5

• Symptoms usually begin in early childhood
• Swollen painful joints occurring spontaneously or with minimal trauma
(haemarthroses)
• Painful bleeding into muscles
• Haematuria
• Excessive bruising or bleeding after surgery or trauma
• FEMALE carriers are usually asymptomatic, but may experience excessive bleeding after trauma
• Generally speaking, bleeding in haemophilia is DEEP (into muscles and joints)

Question 6

Signs on physical examination

Answer 6

• Multiple bruises
• Muscle haematomas
• Haemarthroses
• Joint deformity
• Nerve palsies (due to nerve compression by haematomas)
• Signs of iron deficiency anaemia

Question 7

Investigations

Answer 7

• Clotting screen (high APTT)
• Coagulation factor assays (low factor 8, 9 or 11 (depending on type of haemophilia))
• Other investigations may be performed if there are complications (e.g. arthroscopy)