Necrotizing soft tissue infections developing from pressure ulcers

Aim of the studyNecrotizing soft tissue infections (STIs) are serious complications that may arise from pressure ulcers. However, there are few studies on this important issue. In addition, diagnostic criteria for necrotizing STIs developing from pressure ulcers and infected pressure ulcers are not well established.MethodsWe defined necrotizing STIs developing from pressure ulcers based on clinical findings. Based on the definition, we retrospectively analyzed the medical records of 24 elderly patients with this condition to determine patient age, gender, comorbid disease, laboratory findings, wound location, bacteriology, and treatment outcomes.ResultsIn the examined population, necrotizing STIs developed primarily from pressure ulcers over the sacrum. Dementia and diabetes mellitus were also frequently observed in patients with necrotizing STIs. The average Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score was relatively low. Bacterial cultures from the debrided deep tissues exhibited mixed infections of gram-positive cocci and gram-negative bacilli, except 1 case. Anaerobic pathogens were isolated from 18 patients (72%), and 7 patients (29%) developed bacteremia. None of the cases were preceded by wounds dominated by granulation tissue. Surgical intervention, combined with antibacterial therapy involving intravenous carbapenem or cephem, was successfully used in most cases.ConclusionNecrotizing STIs arising from pressure ulcers are generally caused by mixed pathogens and exhibit symptoms that are milder than those of necrotizing fasciitis caused by group A Streptococcus.