[Subsyndromal delirium in elderly patients: a systematic review]

In this systemic review, the articles published between 1990 and November 2012 on subsyndromal delirium (SSD), and specifically those with reference to geriatric patients, were analysed. In SSD, symptoms from the three nuclear domains of delirium (cognitive, circadian and higher order thinking) are simultaneously present, with mild to moderate severity. Although the search for these clinical characteristics is a useful guide, there are no universally accepted diagnostic criteria for SSD. Regardless of the criteria used for diagnosis, SSD is persistently associated with poor functional and cognitive outcome, longer hospital stay, institutionalisation, and increased mortality. Studies are needed on the physiopathology, treatment and prevention in the field of SSD, which is a particularly important clinical condition in geriatric patients.