TLR4 and delirium: Levels >2 mmol/L promote delirium via three pathways: 1) astrocytic glutamate uptake inhibition (excitotoxicity); 2) microglial TLR4/NF-κB pathway activation (neuroinflammation); 3) cerebral acidosis impairing neurotransmitter dynamics (Qian et al., 2024).