Delirium superimposed on dementia

Purpose Delirium superimposed on dementia (DSD) is a frequent and growing emerging clinical challenge, given the increasing prevalence of dementia. Methods This narrative review focuses on and discusses the current knowledge on epidemiology, pathogenesis, diagnosis and management of DSD. Results There is a close interaction between delirium and dementia since dementia is a risk factor for delirium and delirium is a known risk factor for newly developed dementia or worsening of dementia. The occurrence of DSD causes adverse clinical outcomes. However, DSD is often under-recognized or is frequently considered as the regular course of dementia. Indeed, especially in the advance stages of dementia, DSD diagnosis is challenging since a clear distinction between symptoms attributable to delirium and to dementia is difficult. Given the importance of DSD, it is essential to educate health care providers on the best approach for delirium management and treatment. It is now well recognized that delirium can be prevented using multicomponent interventions carried out by a multidisciplinary team targeting predisposing and precipitating risk factors for delirium. On the contrary, antipsychotics should only be used in patients with severe distressing symptoms and whose behavior means their safety or the safety of those around them is compromised, given the harmful of these medications in patients with pre-existing dementia. Conclusions It is essential to improve health care providers knowledge on DSD to improve the quality of care for an epidemiologically relevant though understudied population. Key summary pointsAim Delirium in patients with dementia (DSD) is highly frequent but often under-recognized and misdiagnosed as dementia. Findings This review discusses the current epidemiology of DSD, its pathogenesis, diagnosis and management. Message Delirium can be diagnosed in patients with dementia though its diagnosis is challenging, especially when dementia is severe. The multiprofessional approach is key to provide the best care to patients with DSD.