Explain a new diagnosis of catheter-related thrombosis and anticoagulation to a parent — OSCE

Candidate instructions

You are the paediatric registrar. You have eight minutes to speak with Mrs Chen, whose six-year-old son Liam has acute lymphoblastic leukaemia and has just been diagnosed with a right femoral deep vein thrombosis around his tunnelled central line, confirmed on ultrasound. Explain in plain language what a clot is and what caused it, the treatment with blood-thinning medicine and how it is given and monitored, the warning signs that mean coming straight to hospital, what will happen to his central line, and whether the family needs to be checked for an inherited clotting problem. Answer her questions, check her understanding, and agree a plan. [1]

Actor brief (parent — Mrs Chen)

You are worried and tired, because Liam has already been through months of chemotherapy. You knew leukaemia could cause complications, but you did not expect a blood clot. You want to know: (1) Did the cancer cause the clot, or was it his central line, or something he was born with? (2) What is the treatment — will he need injections, and for how long? (3) How will you know if it gets worse or moves to his lung — what frightens you most is a clot travelling. (4) Will he have to keep the central line, and is it safe? (5) Does the family need testing, because your husband's sister had a clot after surgery? Push back gently if the candidate uses jargon, dismisses the clot as minor, or does not check your understanding. You settle when you feel the candidate explains the link between the line and the clot honestly, gives you practical guidance on the injections and the warning signs, and addresses the family question without over-testing. [3] [11]

Exemplar candidate approach

Open and acknowledge. "Mrs Chen, thank you for coming in, and thank you for everything you are doing for Liam through his treatment. I know a blood clot is the last thing you expected on top of the leukaemia. I want to explain clearly what the clot is, what caused it, what the treatment is, the warning signs to watch for, what we will do about his central line, and whether the family needs any testing, so together we can make the right plan for him." [1]

Explain the clot and its cause in plain language. "A clot, or what we call a deep vein thrombosis, is a small blockage of congealed blood that formed in one of the deep veins in Liam's right leg. In children, clots almost always happen because of a trigger rather than out of the blue, and in Liam's case there are two triggers working together. The first is his central line — the tube that sits in his vein to give his chemotherapy. That line is essential for his treatment, but it can irritate the vein wall and disturb the blood flow, which is why around half of all childhood clots happen around a central line. The second is the leukaemia and the chemotherapy itself, which can make the blood a little more prone to clotting. So this is a complication of his treatment, not a sign that his leukaemia is getting worse, and it is not your fault." [3] [11]

Explain the treatment honestly. "The treatment is a blood-thinning medicine called low molecular weight heparin — enoxaparin is its name. It does not dissolve the clot that is there, but it stops it getting bigger and gives Liam's body time to dissolve it naturally over the coming weeks. It is given as a small injection just under the skin of his tummy or leg, twice a day. We will teach you and your husband to give it, because most families do it at home, and we will check a blood test called the anti-factor Xa level after a few doses to make sure the dose is right for Liam. He will need it for about six weeks to three months. There is also a newer tablet option called rivaroxaban that some older children can take instead of injections, and we will talk to the haematology team about whether that suits Liam." [7] [4]

Explain the warning signs and the central line. "The most important thing to watch for is the clot moving to his lung, which is called a pulmonary embolism. The signs are sudden breathlessness, chest pain especially when breathing in, coughing up blood, or Liam looking pale and unwell with a fast heartbeat. If any of those happen, you call an ambulance or come straight in — do not wait. The medicine also thins the blood, so watch for unusual bruising, bleeding that will not stop, or blood in his urine or stool, and tell us. As for his central line: we will not remove it straight away, because he still needs it for his chemotherapy. We will keep treating the clot for a few days first so it is safe, and then, if the line is still needed, we keep it; if it can come out, we remove it once the clot has settled." [11] [6]

Address the family question without over-testing. "You asked about your husband's sister's clot and whether the family carries a clotting problem. The honest answer is that most childhood clots like Liam's are caused by the central line and the illness, not by an inherited clotting condition, and we do not usually test for those conditions when the clot is clearly provoked by a line. The reason is that the common inherited changes, like one called factor V Leiden, are quite common in the general population and having them does not usually mean a child will get a clot, so testing can cause worry and labels without changing what we do. We would consider testing if a clot happened without any trigger, if it came back, or if several close relatives had clots at a young age. Your husband's sister having a clot after surgery is worth noting, but on its own it does not mean we need to test Liam right now. If you or the haematology team feel the family history is strong, we can revisit it when Liam is well." [8]

Check understanding and agree a plan. "Can I check — what is your biggest worry right now, and has anything I have said been unclear? Here is what I suggest: we start the enoxaparin injections today, the nurses will teach you and your husband over the next day or two, we check the anti-factor Xa level and adjust the dose, and we review Liam with the haematology team this week. We give you a written plan and a card with the warning signs before you go, and we keep his central line for now and review it with his oncology team. Your experience caring for Liam through all this tells me you will manage the injections well, and we will support you every step of the way. Does that sound right to you?" [1] [2]

Mark scheme (10 marks)

• Empathy and relationship (2): acknowledges the family's burden of treatment, respects the parent's knowledge, plain language, does not minimise the clot or its risks. [3]
• Explains the clot and its provoked cause clearly (2): the central line and the leukaemia or chemotherapy working together, a complication of treatment not a sign of progression, not the parent's fault. [3] [11]
• Explains the treatment with balanced options and monitoring (2): low molecular weight heparin injections twice daily with anti-factor Xa monitoring, the rivaroxaban tablet option, the duration of 6 weeks to 3 months. [7] [4]
• Explains the warning signs and the central line plan honestly (2): pulmonary embolism signs mean coming straight to hospital, bleeding precautions, and the plan to keep or remove the line once the clot has settled. [11] [6]
• Addresses the family and thrombophilia question without over-testing and agrees a plan (2): selective testing, the low positive predictive value of the common abnormalities, the written action plan, and checks understanding. [8] [1]