Authors: J. Ramírez-Bermúdez, L.C. Aguilar, P. León , I. Pérez-Neri, R. Colin-Piana and Camilo Rios
Abstract: Delirium is a neuropsychiatric syndrome characterized by an acute onset and a fluctuating course, with reduction in alertness, global cognitive decline, and marked behavioral disturbances, as well as abnormalities in the circadian rhythm and sleep physiology. The etiology of delirium involves neurological and systemic diseases and substance use disorders as well. A severe mortality rate worsens prognosis if proper treatment is not established promptly. In the neurological setting, delirium is often associated to stroke, epilepsy and preexisting dementia, among other diseases. Although the clinical features of the syndrome are related to cognitive, affective, and volitional functions of the nervous system, concomitant systemic conditions (as infections, dehydration, loss of homeostasis) may trigger or favor the syndrome. It has been proposed that delirium is related, at the neurochemical level, to an abnormal increase of the dopamine system (possibly related to the hyperactive form) and an abnormal decrease in the acetylcholine system (possibly related to the hypoactive form). Drugs affecting the GABA and opioid systems have also been associated to delirium. This review explores the relationship between brain disease and neurotransmitter systems that may shed some light on the pathophysiology of the syndrome.