Significant Pathology in Young Infants Presenting With Hypothermia: A Multicenter Study.

Objective: Hypothermia in young infants is often attributed to immature thermoregulation but may be the harbinger of significant pathology. We aimed to determine the prevalence and type of significant pathology in young infants aged 90 days or younger presenting with hypothermia (≤36.0 °C) and explore associations between this outcome and presenting characteristics and evaluation.

Methods: We conducted a multicenter, retrospective cohort study of young infants evaluated in the emergency department (ED) or hospital setting for hypothermia over a 5-year period. Patients aged 90 days or younger with documented or reported hypothermia in the ED or upon admission were included for study. All charts were manually reviewed. Our primary outcome was a diagnosis of significant pathology, infectious or noninfectious, defined as warranting hospitalization for evaluation, care or monitoring. We used a multivariate logistic regression model to test associations with significant pathology.

Results: Among 998 included infants, 32% (n = 318) had significant pathology, 4% with serious bacterial infection or herpes simplex virus (n = 41) and 28% (n = 277) with other diagnoses of significance spanning multiple organ systems and pathologies. Following multivariate logistic regression, presentation at older age (29-60 days [odds ratio {OR}, 6.9; 95% CI, 4.0-11.9] and 61-90 days [OR, 8.1; 95% CI, 3.8-17.0]), ill-appearance (OR, 4.3; 95% CI, 3.0-6.1), repeated temperature instability (OR, 2.0; 95% CI, 1.4-2.8), and abnormal white blood cell count (OR, 2.5; 95% CI, 1.5-4.1) were associated with significant pathology.

Conclusions: Infants presenting with hypothermia often have diagnoses of significance aside from serious or invasive infections. Decision tools for management of hypothermic young infants should account for alternative pathology.