Clinical factors associated with septic shock in pediatric invasive meningococcal disease: a retrospective study from two tertiary hospitals in Chile, 2009–2025

BackgroundInvasive meningococcal disease (IMD) remains a primary etiology of bacterial meningitis and a cause of long-term neurological sequelae in children. We aimed to describe characteristics of IMD and to identify variables associated with adverse outcomes, defined as septic shock.MethodsA retrospective cohort study included children with microbiologically confirmed IMD hospitalized at two tertiary pediatric hospitals in Santiago, Chile (2009–2025). Data were collected from medical records. Variables associated with the outcome were assessed using Firth’s penalized logistic regression, with candidate variables selected a priori according to clinical relevance, availability at admission, and absence of overlapping with the outcome process.ResultsSeventy-two children were included; 65.3% were male and 54.2% were infants younger than 12 months. Over the 17-year study period, most cases occurred between 2009 and 2014 (n = 51), followed by a marked decline from 2015 to 2025 (n = 21) coinciding with the introduction of the meningococcal ACWY vaccine in the National Immunization Program. The most frequent manifestations at admission were toxic appearance (79.2%), fever (69.4%), gastrointestinal symptoms (69.4%), and irritability or drowsiness (62.5%). The main diagnoses were meningitis with meningococcemia (37.5%), isolated meningitis (25.0%), and meningococcemia (25.0%). Serogroup W (50.0%) and serogroup B (36.1%) predominated. Septic shock occurred in 28 children (38.9%), with a case-fatality rate of 6.9% (5/72); all deaths occurred in children with meningococcemia and none in isolated meningitis. In the primary multivariable model, seizure during hospitalization (aOR 10.63; 2.33–63.90), prolonged capillary refill (aOR 5.75; 1.49–26.21), and petechial or purpuric rash (aOR 4.47; 1.24–18.87), were associated with adverse outcome.ConclusionPediatric IMD remains an important cause of severe disease and mortality. The factors associated with severe outcome reflected three clinically relevant domains: neurological involvement, impaired peripheral perfusion, and vascular manifestations. Because these are simple clinical signs recognizable without laboratory testing, they may support early risk stratification and timely intervention, particularly in resource-limited settings.