THROMBOSIS IN CHILDREN

Question 1

What are the inherited thrombophilias?

Answer 1

Protein C deficiency

Protein S deficiency

Antithrombin deficiency

Factor V Leiden

Prothrombin gene G20210A mutation

Question 2

What are protein C and protein S?

Answer 2

Natural anticoagulants. They are co-factors of each that work by inhibiting the action of FVa and FVIIIa.

Question 3

What is the inheritance pattern of protein C or protein S deficiency?

Answer 3

Autosomal dominant, however, heterozygotes are affected worse than homozygotes.

Question 4

What condition do children with homozygous deficiency of protein C present with?

Answer 4

Purpura fulminans

Question 5

What are the features of purpura fulminans (homozygous deficiency of protein C)?

Answer 5

Life-threatening thrombosis with widespread haemorrhage and purpura into the skin in neonatal period.

Question 6

What is factor V Leiden?

Answer 6

An abnormality in the structure of factor V means that it is resistant to degradation by protein C.

Question 7

What are the acquired disorders which lead to hypercoagulable state in children?

Answer 7

Catheter-related thrombosis

DIC

Hypernatraemia

Polycythaemia - due to congenital heart disease

Malignancy

SLE

Question 8

Which children should be screened for inherited thrombophilias?

Answer 8

Any child with unanticipated or extensive venous thrombosis, ischaemic skin lesions or neonatal purpura fulminans

Any child with a positive family history of neonatal purpura fulminans

Question 9

What are the screening tests for inherited thrombophilias?

Answer 9

Assays for protein C and S

Antithrombin assay

PCR for factor V Leiden

PCR for prothrombin gene mutation