Delirium is a common and serious disorder with high morbidity and mortality. It occurs in 35 to 80 percent of critically ill, hospitalized patients. It may lead to mortality if not detected early. Studies show that delirium causes death in as many as 22 to 76 percent of patients who are hospitalized with delirium. It is often unrecognized and inadequately treated, and this may lead to poor outcome, including long-term care, longer length of stay in hospital, and high impact on health and social expenditure. There may be many reasons that delirium goes undetected, such as not understanding full pathophysiology and not having enough diagnostic tools to detect delirium in the early phase. A clear understanding of neurochemical equilibrium and pathways of the brain will help the clinician to understand the signs and symptoms of delirium. Pathophysiology of delirium is complex, and multiple theories have been proposed to explain its exact pathophysiology, but none of these mechanisms have been fully understood. Early detection of delirium and reduction of modifiable risk factors, along with better management, can result in better outcomes. This article discusses the pathophysiology and parts of brain involved in delirium as well as mood and psychotic symptoms of delirium.
Keywords: Delirium; delusion; drugs; hallucination; inflammatory; neuroanatomic; neuroimaging; neurotransmitter; oxidative metabolism; pathophysiology; predisposing factors; psychotic; sleep; treatment.