Persistent Inflammation, Immunosuppression, and Catabolism Syndrome and Serious Infections in Burn-Injured Adults: A Retrospective Single-Center Study from 1997 to 2023

Alterations in both the innate and adaptive immune systems can induce a significant immunocompromised state among those hospitalized after burn injury. These changes can devolve into the clinical entity known as persistent inflammation, immunosuppression, and catabolism syndrome (PIICS), characterized by profound and chronic immune dysregulation. Persistent inflammation, immunosuppression, and catabolism syndrome is defined by the presence of lymphopenia, elevated C-reactive protein levels, and evidence of catabolism through weight loss or hypoalbuminemia in the context of a prolonged hospitalization. Though PIICS has previously been described in patients with burn injuries, this immunophenotype in the setting of serious bacterial and fungal infections is poorly characterized. We performed a detailed retrospective analysis of burn-injured adults (aged 19-64 years) in a de-identified institutional database of patient medical records from 1997 to 2023. Of the 960 patients admitted for a primary burn injury, the overall prevalences of serious infections and PIICS was 38% and 25%, respectively. Both the presence of an inhalation injury and the total body surface area (TBSA) burn size correlated with the development of serious infections and PIICS. Patients with PIICS had more pathogens isolated and a higher prevalence of Acinetobacter and Stenotrophomonas infections. The immunophenotype of PIICS was strongly associated with recurrent infections during hospitalization. Detailed assessments of PIICS criteria, including trends in lymphocyte counts, may help identify the development of serious bacterial and fungal infections in burn-injured adults.