Key Concepts
Introduction
Neonates have an immature immune system with deficient complement activation, reduced neutrophil chemotaxis and phagocytic activity, limited immunoglobulin production (primarily relying on transplacental maternal IgG), and poor opsonization. Early-onset sepsis (EOS, within 72 hours of birth) is typically caused by vertical transmission of maternal organisms during labor and delivery. Group B Streptococcus (GBS) remains the most common pathogen, followed by E. coli. Inflammatory cascade activation causes cytokine release leading to vasodilation, capillary leak, and multi-organ dysfunction. Neonates may not mount a fever and instead present with hypothermia, reflecting their inability to generate an adequate inflammatory response. On the exam, writers often pair stable-sounding options with unstable data—notice the mismatch before you commit. If the stem names a license or role, reread that line; scope errors are classic trap answers even when the clinical topic is familiar. Run a 60-second scan: breathing work and oxygenation, perfusion and end organs, neuro baseline, likely infection sources, and devices that can fail quietly. When two answers feel partly right, pick the one that reduces imminent harm and matches orders for the role you were...