Fragile immunity, fatal foe: A cluster of Pneumocystis jirovecii pneumonia cases in children with haematological malignancies on chemotherapy

BACKGROUND: Pneumocystis jirovecii causes a potentially fatal interstitial pneumonia, especially in immunosuppressed hosts. It was the most common cause of death in children with leukaemia, before the introduction of prophylaxis. AIMS: In this study, we evaluated the clinical and demographic characteristics of proven PJP cases in children with haematological malignancy on chemotherapy. The study also determined the association of PJP characteristics with various phases of chemotherapy. METHODS: This was a retrospective study conducted at a tertiary care teaching hospital in Delhi. Cases included 13 children less than 12 years of age with leukaemia on chemotherapy with proven PJP diagnosis, according to the EORTC/MSGERC guidelines. For microbiological diagnosis, direct immunofluorescence was performed using the Merifluor® Pneumocystis kit manufactured by Meridian Bioscience Inc. RESULTS: B-cell acute lymphoblastic leukaemia was the most common haematological malignancy seen in these cases. Most of the PJP cases were seen in the maintenance phase of chemotherapy. The clinical profile of the PJP cases includes fever, cough, cytopenia, hypoxaemia, coryza, dyspnoea, and hepatitis. The radiological findings of the PJP cases include bilateral diffuse ground-glass opacification, perihilar infiltrates, and unilateral infiltrates. The mortality rate of the PJP cases was 15.4%. CONCLUSIONS: Pneumocystis jirovecii causes a potentially life-threatening pneumonia, especially in immunocompromised individuals such as children with leukaemia on chemotherapy. PJP presents more severely with rapid progression and higher mortality rate in children with leukaemia than in HIV-positive cases. Therefore, early diagnosis and prompt treatment initiation is paramount in reducing morbidity and mortality in these cases.