Background: While delirium in the adult, and particularly the older adult patient, is well documented, the incidence of delirium among hospitalised children is elusive. Yet retrospectively, up to 30% of children who had been hospitalised recall having hallucinatory experiences during their hospital stay The majority of these were highly disturbing memories with persistent and threatening content (98%). Except in two cases, the location associated with these memories was the paediatric intensive care unit (PICU).

Objective: The purpose of this study was to examine the evidence on risk factors and characteristics of acute paediatric delirium.

Method: Using the systematic review method within an epidemiological framework of person, time and place, a total of 52 studies were selected for retrieval and 21 (N=2616) were included in this review after assessment for methodological quality using JBI tools validated for this purpose.

Findings: There are 5 primary characteristics seen in children experiencing delirium: inattention, agitation, sleep-wake cycle disturbances, impaired orientation and hallucinations, usually visual. Children who were more seriously ill, such as those in PICU and with a high PRISM-II score, and children who were mechanically ventilated were at greater risk for development of delirium. Those with a developmental delay or a pre-existing anxiety disorder were more also prone to delirium. In the two studies that reported the effect of race on development of delirium, 70% and 79% of the children, respectively, were Caucasian. Although delirium symptoms fluctuate, most episodes occurred at night. Boys were slightly, but not significantly, more susceptible than girls. An important finding was that across the 21 included studies, 28.9% of children (N=758) were diagnosed with delirium.

Conclusion: Early recognition and management of paediatric delirium may help prevent unnecessary laboratory testing and imaging studies that increase overall hospital cost as well as inflict unnecessary pain and anxiety on children.