title: Cholinergic deficiency hypothesis in delirium: a synthesis of current evidence.
abstract: Deficits in cholinergic function have been postulated to cause delirium and cognitive decline. This review examines current understanding of the cholinergic deficiency hypothesis in delirium by synthesizing evidence on potential pathophysiological pathways. Acetylcholine synthesis involves various precursors, enzymes, and receptors, and dysfunction in these components can lead to delirium. Insults to the brain, like ischemia and immunological stressors, can precipitously alter acetylcholine levels. Imbalances between cholinergic and other neurotransmitter pathways may result in delirium. Furthermore, genetic, enzymatic, and immunological overlaps exist between delirium and dementia related to the cholinergic pathway. Important areas for future research include identifying biomarkers, determining genetic contributions, and evaluating response to cholinergic drugs in delirium. Understanding how the cholinergic pathway relates to delirium may yield innovative approaches in the diagnosis, prevention, and treatment of this common, costly, and morbid condition.
authors.affiliation: Warren Alpert Medical School of Brown University, Providence, RI, USA.
authors.forename: Tammy T
authors.initials: TT
authors.lastname: Hshieh
authors.forename: Tamara G
authors.initials: TG
authors.lastname: Fong
authors.forename: Edward R
authors.initials: ER
authors.lastname: Marcantonio
authors.forename: Sharon K
authors.initials: SK
authors.lastname: Inouye
mesh_terms: D000109:Acetylcholine / Q000172:deficiency / Q000378:metabolism / Q000502:physiology*; D001921:Brain / Q000378:metabolism; D003693:Delirium / Q000209:etiology / Q000503:physiopathology*; D003704:Dementia / Q000503:physiopathology; D006801:Humans; D018377:Neurotransmitter Agents / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000502:physiology
chemical_list: D018377:Neurotransmitter Agents; D017981:Receptors, Neurotransmitter; D000109:Acetylcholine