Venous thromboembolism, pulmonary embolism and thrombophilia in children — branching viva

Examiner opening (Examiner)

You are the general paediatric registrar on the ward. A six-year-old boy with acute lymphoblastic leukaemia, three months into induction chemotherapy with a tunnelled central venous catheter, presents with a swollen warm right leg over 48 hours. A compression ultrasound confirms a right femoral deep vein thrombosis. Talk me through your assessment and management plan. ^[3]

Exemplar opening (Candidate)

This boy has a provoked deep vein thrombosis. The central venous catheter is the dominant provoking factor in paediatric thrombosis, accounting for around half of all events, and the leukaemia itself and the induction chemotherapy — particularly asparaginase, which depletes antithrombin — create a hypercoagulable state. The combination is classic. My management is to start therapeutic anticoagulation with low molecular weight heparin, enoxaparin 1 mg per kg subcutaneously every 12 hours, check the anti-factor Xa level after the third or fourth dose with a target of 0.5 to 1.0 IU per mL for twice-daily dosing, treat for 6 weeks to 3 months, and remove the central line once it is no longer needed and the clot has stabilised. I will involve the paediatric haematology team early. ^{[1] [7]}