Delirium

Abstract

The Latin verb ‘delire’ (to be deranged, crazy, out of one’s wits) appears in the Coventry mystery plays in 1400. Other accounts from literature include Shakespeare’s death of Falstaff (a babbled of green fields), Lady Macbeth sleepwalking and Tolstoy’s depiction of Anna Karenina’s post-partum delirium.

Many terminologies have been used interchangeably for delirium such as, ‘acute confusional state’, ‘acute organic brain syndrome’, ‘acute brain failure’ and ‘post-operative psychosis’. The definitions may embrace all varieties of acute organic reaction, sometimes referring to the degree of overt disturbance or confine the term to a clinical picture with specific features.

The Oxford English dictionary defines delirium as a ‘disordered state of the mental faculties resulting from disturbances of the functions of the brain, and characterized by incoherent speech, hallucinations, restlessness and frenzied or manic excitement’. The NICE guideline for delirium describes delirium as a ‘common clinical syndrome characterized by disturbed consciousness, cognitive function or perception, which has an acute onset and fluctuating course’. The NICE guideline emphasises that delirium is a serious condition and associated with poor outcomes, but that it can be prevented and treated if dealt with urgently.

The broad characteristics of delirium have been well documented: wakefulness with ability to respond verbally, increased psychomotor activity, pronounced disturbance of affect, defective reality testing or symptoms such as delusions and hallucinations.