What is delirium?
Delirium is a disturbance in awareness, attention, and cognition developing over a short period of time and represents a decline from baseline.
Delirium tends to fluctuate in severity temporally and is a result of another medical condition, or withdrawal, or exposure to toxins, as evidenced by history, physical examination, or laboratory findings.
The differential diagnosis of delirium can include infections, withdrawal from drugs of abuse, acute metabolic disorder (like electrolyte imbalance or hepatic or renal failure), trauma, central nervous system pathology (like stroke, hemorrhage, tumor, seizure disorder), hypoxia, vitamin or mineral deficiencies, endocrine dysfunction, acute vascular injury (shock, hypertensive encephalopathy), toxins (including drugs of abuse and medications like anesthetics, narcotics, anticholinergics, steroids, etc.), or heavy metal poisoning or can be due to multiple etiologies.
Characteristically delirium cannot be explained by either a preexisting or evolving NCD.
However, patients with an underlying NCD are more vulnerable to delirium because of their baseline impaired brain function.
Sleep–wake cycle disturbances and emotional lability could also be associated with delirium, but there are no known psychiatric illnesses where the initial presentation is a delirium-like state.
Another important distinction between delirium and dementia is the acute onset and temporal fluctuations characteristic of delirium in contrast to the chronic nature of dementia.
