Haemophilia

Question 1

What is haemophilia?

Answer 1

A rare CLOTTING disorder.

Question 2

Inheritance of haemophilia?

Answer 2

X-linked recessive

Question 3

What are the 2 main types of haemophilia?

Answer 3

A & B

Question 4

What is Haemophilia A characterised by?

Answer 4

Factor VIII deficiency

Question 5

Which type of haemophilia is most common?

Answer 5

A

Question 6

What does haemophilia B arise due to?

Answer 6

Factor XI deficiency

Question 7

Pathophysiology of haemophilia?

Answer 7

1) Factor VIII or IX deficiency interferes with the intrinsic pathway of the coagulation cascade

2) Decreased activation of Factor X to Xa

3) Reduces generation of thrombin (thrombin is critical for converting fibrinogen to fibrin)

4) Clot is fragile and susceptible to premature lysis

5) Manifests as prolonged bleeding

Question 8

Where does bleeding typically occur in haemophilia?

Answer 8

Bleeding into deep tissues e.g. muscles & joints

Question 9

What is the severity of symptoms in haemophilia generally proportionate to?

Answer 9

The degree of factor deficiency

Question 10

What is haemophilia B also known as?

Answer 10

Christmas disease

Question 11

What clotting factor is deficient in haemophilia A?

Answer 11

Factor VIII

Question 12

What clotting factor is deficient in haemophilia B?

Answer 12

IX

Question 13

What is haemophilia C?

Answer 13

Rosenthal syndrome.

It is a deficiency of clotting factor XI that is inherited in an autosomal recessive pattern.

Question 14

How does inheritance of haemophilia impact who is affected?

Answer 14

X-linked recessive nature means men are almost exclusively affected.

Question 15

Features of haemophilia?

Answer 15

1) Haemarthrosis (bleeding into a joint)

2) Easy bruising

3) Prolonged bleeding after dental procedure

4) Muscular haematomas e.g. quads, calves

5) Epistaxis

6) GI symptoms e.g. melaena or haematemesis

Question 16

How does haemoarthrosis typically present?

Answer 16

Painful, erythematous, stiff and swollen joint

Classically the knees, ankles and elbows.

Question 17

A significant portion of cases of haemophilia present in the neonatal period (40%).

What features may be seen in neonates?

Answer 17

1) Prolonged bleeding after circumcision

2) Intracranial bleeding (up to 5% of severe cases)
- Can be due to trauma from delivery ie forceps

3) Prolonged bleeding after heel prick testing

Question 18

When should haemophilia be suspected?

Answer 18

In younger patients with prolonged hemorrhage, ecchymosis (bruising) or haemarthrosis.

Question 19

Bloods tests in haemophilia?

Answer 19

1) FBC –> look specifically for thrombocytopenia to rule out platelet dysfunction.

2) Clotting studies

3) LFTs –> to rule out liver synthesis dysfunction

4) Factor VIII and IX assays

5) Von Willebrand factor antigen testing.

Question 20

What clotting study result represents a delay in the intrinsic coagulation pathway? (i.e. one of the hallmarks of haemophilia)?

Answer 20

Prolonged activated partial thromboplastin time (aPTT)

Question 21

Why is prothrombin time (PT) useful in haemophilia diagnosis?

Answer 21

A normal PT can rule out extrinsic and common coagulation pathway pathologies that could present similarly e.g. liver disease.

Question 22

What is the most common differential diagnosis to consider in haemohpilia?

Answer 22

von Willebrand disease

Question 23

Mx of haemophilia?

Answer 23

Replacing missing coagulation factors:

A –> VIII
B –> IX

Question 24

What medications is it important to avoid in haemophilia?

Answer 24

Aspirin & NSAIDs

Question 25

Complications of haemophilia?

Answer 25

1) Compartment syndrome related to muscular bleeding

2) Arthropathy from haemarthrosis

3) Severe haemorrhage (Intracranial, GI)