Pathophysiology and biomarkers of delirium in older adults-Narrative review.

BACKGROUND: Delirium is a frequent acute neurocognitive syndrome in older adults, associated with morbidity, mortality, and long-term cognitive decline. Its pathophysiology is multifactorial and not yet fully understood. OBJECTIVE: To summarize clinically relevant concepts of delirium pathophysiology and emerging biomarkers. METHODS: Narrative review of literature from 2010-2026, prioritizing human studies, reviews, meta-analyses, and clinically relevant pathophysiological literature relevant to older hospitalized or perioperative patients. RESULTS: Delirium arises from the interaction of predisposing vulnerability and acute triggers. Relevant mechanisms include neuroinflammation, neurotransmitter imbalance, neurodegeneration, metabolic dysfunction and blood-brain barrier impairment. Biomarker research has identified promising candidates, including inflammatory, neurodegenerative, metabolic and stress-related markers but none is currently established for routine clinical use. CONCLUSION: Delirium prevention remains clinically driven. Multimodal biomarkers may support future risk stratification but require prospective validation.