Haemophilia

Question 1

Define

Answer 1

Bleeding diatheses resulting from an inherited deficiency of a clotting factor

(1) Haemophilia A (most common) → caused by a deficiency in factor VIII
(2) Haemophilia B → caused by a deficiency in factor IX (also called Christmas disease)
(3) Haemophilia C (rare) →caused by a deficiency in factor XI

Question 2

Causes

Answer 2

• Haemophilia A and B exhibit X-linked recessive inheritance
• Variety of genetic mutations in FVIII and XI genes
• 30% are new mutations with no FHx
• Due to its inheritance pattern, Haemophilia is mainly seen in MALES

Factor VIII is a vital co-factor in the intrinsic pathway of the coagulation cascade
Activated factor IX activates factor X (converts factor X →Xa)

Question 3

Epidemiology

Answer 3

Symptoms usually begin in early childhood (or after surgery/trauma)

Haemophilia C is more common in Ashkenazi Jews.

Question 4

Symptom

Answer 4

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 5

Signs

Answer 5

• Multiple bruises
• Muscle haematomas, haemoarthroses, joint deformities
• Nerve palsies (due to nerve compression by haematoma) or compartment syndrome
• Signs of Fe-deficiency anaemia

↑APTT, ↓FVIII/FIX assay

Question 6

Investigated

Answer 6

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)