However, in the majority of situations, an appropriate history, an analysis of the patient's treatments, a rigorous physical examination, and a blood biology examination are sufficient to quickly identify and treat the cause(s) of the confusional syndrome. In the practice of emergency departments, a brain scan without injection of contrast medium is nevertheless frequently prescribed for an elderly person presenting a recent alteration of his cognitive functions. One explanation is that clinical signs suggestive of intracranial lesion may be more difficult to detect in frail elderly patients with a significant history, in the same way as those of sepsis for example. On the other hand, an alteration of the cognitive function without any known antecedents for the patient, probably leads emergency physicians to suspect too frequently a central neurological cause. However, the cause is most often of extracerebral origin.

At Paris Saint Joseph Hospital, the number of emergency room visits increased by 4% between 2018 and 2019. The Emergency Department is the second largest emergency department in Ile de France in terms of attendance of a geriatric patient base (20% of patients seen). These observations prompt an urban emergency department like ours to evaluate the relevance and quality of our geriatric emergency medicine practices.

In the literature, several American studies, mostly monocentric and retrospective, have examined the diagnostic utility of brain scans in elderly patients with confusional syndromes during their observation in the emergency department. The discovery of a scannographic abnormality explaining the symptomatology occurred in 10 to 39% of cases depending on the series. The patient cohorts differed in terms of age and clinical presentation. Some were predominantly composed of patients with a focal neurological sign associated with confusion, others exclusively of patients with head trauma. We did not find any study that specifically evaluated the diagnostic contribution of an emergency brain scan in the elderly patient ≥ 75 years of age with isolated confusion, i.e., in the absence of a neurological localizing sign and in the absence of a head injury under antiplatelet therapy (AAP) and/or anticoagulant therapy, for which the indication of brain imaging is not debatable. One study evaluated the diagnostic yield of brain scans in the emergency department in adult patients with an acute delirious episode. However, it was more about exploring a first psychiatric episode in rather young patients. This problem appears interesting in the confused elderly subject because the realization of a CT scan is time-consuming, expensive, and irradiating. It has an impact on the length of stay in the emergency department, the prolongation of which is itself a source of a confusional episode, with its share of complications: fall, agitation, disorientation, mechanical restraint, inappropriate use of benzodiazepines and neuroleptics, for example.

Given the ageing of the population, the morbidity of confusional episodes in the elderly in the absence of rapid adapted treatment, and the frequent saturation of emergency departments, it is useful to know the real diagnostic yield of the brain scan performed for an isolated confusional syndrome observed in the elderly in the emergency department. At the same time, in France, targeted studies have highlighted an unregulated growth in the prescription of certain medical imaging procedures. Possible reasons for this include the practice of defensive medicine by extension of the precautionary principle, and the high expectations of patients, their relatives, or treating physicians, who may exert pressure to prescribe. Finally, acting also under the pressure of time management, where the clinical time spent with each patient tends to be reduced, it is paradoxical that the prescription of brain imaging examinations has increased in the emergency department in recent years. Determining the organizational impact on the duration of care would allow us to meet a quality of care objective.