Preventing Delirium: identification of risk groups in elderly patients with acute medical condition

Abstract

Background: Delirium is a frequent neuropsychiatric syndrome associated with serious outcomes affecting mainly elderly subjects with acute medical disorders. Although it is widely accepted that delirium is the result of an interplay between predisposing and precipitating factors, the specific role of a particular risk factor remains largely unknown. Exploring how the etiological factors interact with each other can facilitate the early diagnosis of delirium and clarify the pathophysiological mechanisms involved in this condition. Objectives: Explore how risk factors of delirium co-occur in medically-ill elderly patients with this syndrome and identify sub-groups of those risk factors. Materials and Methods: Sociodemographic characteristics, acute medical conditions and chronic medical comorbidities were characterized in a group of 82 acutely-ill medical elderly patients diagnosed with delirium (CAM and DSM-IV-TR). A hierarchical cluster analysis of all risk factors was carried out using SPSS 22. Results: With the hierarchical cluster analysis the cases could be grouped into two main clusters. Patients included in cluster 1 [45 cases] had higher rates of osteoarthropathy, cancer, urinary tract infection and hyponatraemia, while cluster 2 [36 cases] was characterized by valvulopathy, atrial fibrillation, heart failure, acute pulmonary insufficiency and pneumonia. Discussion and Conclusion: Based on clinical characteristics, we identified two subgroups of delirious patients with different pattern of risk factors. Cluster 1 reflects deregulation states of different physiological mechanisms during delirium since patients in this cluster seem to have disorders affecting multiple organs/systems. Common pathophysiological pathways are likely to include systemic inflammation, pain and electrolyte imbalance. Cluster 2 was constituted by cardiopulmonary symptoms that are associated with both chronic and acute reduction of blood flow and/or oxygenation to the brain which can lead to cerebral hypoperfusion and a 2 neurovascular unit energy crisis. Known predisposing factors of delirium, such as age and pre-existing dementia, were similar between groups.