Explaining invasive fungal disease and central-line removal — OSCE

Candidate instructions (8-minute station)

You are the paediatric registrar on the oncology ward. A 7-year-old boy with acute lymphoblastic leukaemia, on day 12 of induction chemotherapy, has been profoundly neutropenic with a central venous catheter in situ. His blood cultures, drawn because of persistent fever, have grown Candida. The oncology team has decided to remove the central line and to start an intravenous antifungal. His parents are frightened: the fever was hard enough, and now they are being told their son has a "blood fungal infection," that his line must be pulled, and that he will need weeks of a new intravenous medicine. They are worried the line removal will derail his chemotherapy. [14]

Your tasks are: [2]

1. Explain in plain language why a child with a central line and low immunity developed a fungal bloodstream infection, and why the line itself is part of the problem and must come out. [2] [14]
2. Explain what the intravenous antifungal does, why it is given through a drip rather than by mouth at this stage, and what the team will watch for (kidney function, electrolytes, drug levels). [2]
3. Explain why the ophthalmology team will examine his retinas, and what the two-week minimum duration means in terms of repeated blood cultures and follow-up. [14]
4. Address the parents' worry about the chemotherapy, and explain how the team will protect the next cycle with prophylaxis. [1]

You are not expected to give exact antifungal doses to the parents; explain the plan in plain language and flag that any decision is made by the oncology and infectious-diseases teams with the parents' consent. [14]

Examiner prompt to the actor (mother)

"He's already been through so much with the leukaemia, and now you're telling me he's got a fungus in his blood? How did that even happen — he's in hospital, isn't he meant to be safe here? And why do you have to take his line out? That line is how he gets his chemo. Won't pulling it out set everything back? And how long is this fungal medicine going to go on for?" [14]

Marking domains

• Frame and explanation (3): explains in plain, non-judgemental language that the central line is a highway for skin organisms into the bloodstream when the white-blood-cell count is very low, and that removing the line is part of curing the infection, not an admission of failure; names that the fungus is a yeast that has entered the blood and must be cleared before it can settle in the eyes, the heart or the brain. [2] [14]
• Antifungal rationale and monitoring (3): explains that the intravenous antifungal is needed because the infection is in the bloodstream and the child's immunity is low, that it is given through a drip to reach effective blood levels, and that the team will monitor the kidneys, the salts in the blood, and the drug level to keep the medicine safe; names that the length of treatment depends on the blood cultures clearing. [2]
• Retinal examination and duration (2): explains that the fungus can settle in the back of the eye, so the eye team will examine his retinas to be sure, and that the team will keep taking blood cultures until they are clear and then treat for a minimum of two weeks more to be certain the infection is gone. [14]
• Chemotherapy reassurance and prophylaxis (2): acknowledges the worry about the chemotherapy without dismissing it, explains that a new line can be placed once the infection is cleared and that the chemotherapy timing will be decided with the oncology team, and explains that a protective antifungal medicine during the next cycle reduces the chance of this happening again. [1]

Model answer — the explanatory script

"Thank you for coming in, and I can hear how frightening this is. Let me explain what has happened, what we are doing, and why each step matters, because they are all connected." [14]

"Your son has been very low on neutrophils — the white blood cells that fight infection — because of the chemotherapy. That is expected, and it is why we have been watching him so closely. The central line, the one he has had for his chemotherapy, is wonderful for giving medicines, but it also gives skin organisms a route into the bloodstream. When the neutrophils are very low, a fungus called Candida — a yeast that lives on the skin and in the gut — can travel up that line and into the blood. That is what the culture has shown. It is not a failure of care; it is a recognised risk of this combination — the line and the low counts together." [2] [14]

"Now, why does the line have to come out? Because the fungus can sit on the line itself, forming a kind of film that the medicine cannot fully reach. If we leave the line in, the infection often comes back even while we are treating it. Removing the line removes the source, and it shortens the time your son needs the antifungal. I know the line is how he gets his chemotherapy, and I know pulling it out feels like a step backwards. The oncology team will plan a new line once the infection is cleared, and the chemotherapy timing will be decided together with them — but right now, clearing this infection is the priority, and the line is part of the infection." [2] [14]

"The medicine we are giving is an antifungal through a drip. We use a drip rather than a tablet at this stage because the infection is in the bloodstream and we need strong, reliable levels quickly. Like all medicines, it has things we watch for — it can affect the kidneys and the salts in the blood, so we are checking his blood tests regularly, and some of these medicines need a level check to keep the dose right. The length of treatment depends on the blood cultures clearing: we keep taking cultures, and once they are negative we treat for a minimum of two weeks more, to be certain." [2]

"One more thing the team will do is ask the eye doctors to look at the back of his eyes — his retinas. That is because the fungus, if it travels in the blood, can settle there, and we want to be sure it has not. It is a quick examination, and it is part of making sure we have found and treated every part of the infection." [14]

"And for the future — I know you will be worried about this happening again — for the next chemotherapy cycle, the team will use a protective antifungal medicine, a kind of preventive, to lower the chance of this recurring. There is good evidence that this kind of protection reduces fungal infections during these high-risk cycles. The oncology and infectious-diseases teams will plan all of this with you." [1] [14]