Specifically, the systemic inflammatory response syndrome triggered by surgical trauma and stress exacerbates central nervous system inflammation through multiple pathways: (1) increased blood-brain barrier permeability, (2) activation of microglia and astrocytes, and (3) subsequent release of proinflammatory cytokines (eg, IL-1β, IL-6, and TNF-α) into the central nervous system. Here, TNF is linked to systemic inflammatory response syndrome.