Fungal infections in immunocompetent and immunocompromised children — branching viva

Opening question

Examiner: Take me through this child. What is your frame for managing him, and what is at the top of your differential? ^[14]

Candidate: My frame is persistent febrile neutropenia with a high probability of invasive fungal disease. A profoundly neutropenic child (ANC 0.1) with a central line and fever persisting beyond four to seven days on appropriate broad-spectrum antibiotics has crossed the threshold where empirical antifungal therapy is mandatory. The pleuritic chest pain points toward an invasive pulmonary mould process. At the top of my differential is invasive pulmonary aspergillosis, with invasive candidiasis (line-related) and mucormycosis also in play, alongside unresolving bacterial infection. ^{[14] [1]}

Examiner: Why is persistent febrile neutropenia the trigger for empirical antifungal therapy? ^[1]

Candidate: Because the probability of an invasive fungal infection rises sharply after four to seven days of persistent fever in profound neutropenia, and the neutrophil that would contain the organism is absent. The cultures and biomarkers lag the clinical deterioration, so waiting for confirmation costs the child time. An echinocandin or liposomal amphotericin B is started empirically, and the chest and sinuses are imaged. The principle is that a missed or delayed invasive fungal disease in the neutropenic child is measured in lives, not in days of unnecessary therapy. ^{[1] [14]}