Leukopenia in children receiving intensive care is indicative of increased risk of unfavourable outcomes and mortality, according to a study published in the December 2022 issue of the Journal of Paediatrics and Child Health.¹

In this study, researchers included 200 children hospitalized in the pediatric ICU from June 2018 to August 2018. Children with pre-existing immune deficiency and those diagnosed with a malignancy were excluded from the study group. The median age of the participants was 2.2 years. Thirty-nine (20%) children were admitted to the PICU due to respiratory illnesses. A little over half (52%; n = 103) were post-surgery patients; of these, 68 (34%) had undergone cardiac surgery.

Sixty-three (31.5%) children had lab-confirmed infections. In the first week of their stay in the PICU, 135 (67.5%) had leukopenia; 117 (58.5%) out of these 135 patients had only lymphopenia, 16 (8%) had both lymphopenia and neutropenia, while 2 (1%) patients just had neutropenia.

Follow-up blood count data was available for 69 children; 33 had resolution of lymphopenia within 48 hours of their stay in the ICU. In 20 (29%) children, the lymphopenia corrected by 4 days, while in 10 children, the lymphopenia improved in a week.

Children with lymphopenia were more likely to undergo cardiac surgery, the cardiopulmonary bypass time was longer; they also required invasive ventilation and treatment with vasopressor/inotrope and consequently prolonged hospitalization. The chances of organ failure on the 4^th day of admission was higher among children with lymphopenia.

This study highlights the role of leukopenia as a marker of “altered immunity” in critically-ill children in PICU predisposing them to the risk of infections and thereby of adverse prognosis. It is a simple and easily available marker to identify at-risk patients. The authors however suggest more studies with follow-up of blood counts “to determine the course and outcomes of lymphopenia”.

Reference

1. Nallasamy K, et al. Prevalence and outcome of lymphopenia in the Paediatric Intensive Care Unit: A prospective observational study. J Paediatr Child Health. 2022 Dec;58(12):2203-2210. doi: 10.1111/jpc.16183.