Haemophilia

Question 1

What is Haemophilia?

Answer 1

Bleeding diatheses resulting from an inherited X-linked recessive pattern causing deficiency of a clotting factor

Question 2

What are the 3 subtypes of haemophilia? Describe the prevalence of each?

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

What is acquired haemophilia?

Answer 3

suddenly appearing autoantibodies that interfere with factor 8: much rarer + no genetic inheritance pattern

Question 4

Describe the inheritance of haemophilia

Answer 4

A + B: X-linked recessive inheritance

Question 5

Describe the aetiology of haemophilia A

Answer 5

usually due to a flip tip inversion in factor VIII gene in the X chr, but may be due to other genetic alterations

Question 6

Describe the aetiology of haemophilia B

Answer 6

behaves clinically like haemophilia A,
Mainly due to point mutations + deletions
33% of cases are new mutations

Question 7

Who is haemophilia usually seen in? Why? What are the exceptions to this?

Answer 7

Due to its inheritance pattern, mainly seen in MALES, but F carriers may have some bleeding sx
Rare cases of F having haemophilia e.g. in Turners, extreme lyonization, etc

Question 8

Describe the epidemiology of haemophilia

Answer 8

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

Question 9

List 4 symptoms of haemophilia

Answer 9

Hx of recurrent or sever bleeding: spontaneous or trauma induced
Swollen painful joints occurring spontaneously or with minimal trauma (haemarthroses)
Painful bleeding into muscles causing haematomas
Excessive bruising or bleeding after surgery or trauma

Question 10

When do symptoms of haemophilia usually present?

Answer 10

Early childhood, or after surgery/trauma

Question 11

How do female carriers usually present in haemophilia?

Answer 11

Usually asymptomatic, but may experience excessive bleeding after trauma

Question 12

Describe the nature of bleeding in haemophilia

Answer 12

DEEP (into muscles + joints)

Question 13

List 6 signs of haemophilia

Answer 13

Multiple bruises
Muscle haematomas: mainly ocurs in quads, hamstrings, biceps, iliopsoas, + triceps
Haemarthroses
Joint deformity
Nerve palsies (due to nerve compression by haematomas)
Signs of iron deficiency anaemia

Question 14

What test and results are highly suggestive of haemophilia?

Answer 14

Clotting screen (high APTT)
If corrected after a mixing study (when norm plasma is incubated into pt for 2 hours) then highly suggestive of haemophilia

Question 15

What assays are taken in haemophilia?

Answer 15

Coagulation factor assays (low factor 8, 9 or 11)

VWf assay: Exclude von Willebrands disease

Question 16

Why may other investigations be performed in haemophilia?

Answer 16

if there are complications (e.g. arthroscopy)

Question 17

Why perform an FBC in haemophilia?

Answer 17

Exclude thrombocytopenia as cause of bleeding
Identify anaemia is present due to severe or prolonged bleeding
Check LFTs: liver dysfunction can contribute to prolonged APTT

Question 18

What can bleeding into joints and formation of haematomas lead to?

Answer 18

High pressure can lead to nerve palsies + compartment syndrome