Postoperative neurocognitive disorders in the elderly: how can we stop the harm? A literature review

Figure 1. The updated nomenclature timeline of perioperative neurocognitive disorders. The new guideline classifies perioperative neurocognitive disorders (p-NCD) based on their onset and duration, outlining their progression from postoperative delirium (POD) (up to 7 days) to delayed neurocognitive recovery (up to 30 days), postoperative neurocognitive disorders (PND) (up to 12 months), and persistent neurocognitive disorders (beyond 12 months).

Figure 2. Neuroinflammatory cascade following surgical trauma and its role in postoperative neurocognitive disorders. Surgical trauma induces a systemic inflammatory response, leading to the release of proinflammatory cytokines and molecules such as IL-1β, IL-6, TNF-α, and HMGB1 into the bloodstream. These mediators enter the cerebral circulation, where they act upon endothelial cells of the blood–brain barrier (BBB), disrupting tight junctions and increasing permeability. The resulting uncontrolled influx of peripheral inflammatory molecules into the CNS contributes to neuroinflammation and oxidative stress. Within the CNS, proinflammatory cytokines activate resident immune cells, including astrocytes and microglia, initiating a pathological inflammatory response. Activated microglia and astrocytes release cytotoxic mediators, including glutamate, complement proteins, reactive oxygen species (ROS), and nitric oxide (NO). This excessive neuroinflammatory response leads to neuronal dysfunction, synaptic impairment, and neurotoxicity, which may result in transient or permanent changes to the local neuronal cells. IL-1β, Interleukin 1 beta; IL-6, Interleukin 6; TNF-α, tumor necrosis factor…