How do delirium motor subtypes differ in phenomenology and contributory aetiology? a cross-sectional, multisite study of liaison psychiatry and palliative care patients.

OBJECTIVES: To investigate whether delirium motor subtypes differ in terms of phenomenology and contributory aetiology. DESIGN: Cross-sectional study. SETTING: International study incorporating data from Ireland and India across palliative care, old age liaison psychiatry and general adult liaison psychiatry settings. PARTICIPANTS: 1757 patients diagnosed with delirium using criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM IV). PRIMARY AND SECONDARY OUTCOME MEASURES: Hyperactive, mixed and hypoactive delirium subtypes were identified using the abbreviated version of the Delirium Motor Subtype Scale. Phenomenology was assessed using the Delirium Rating Scale Revised. Contributory aetiologies were assessed using the Delirium Aetiology Checklist (DEC), with a score >2 indicating that the aetiology was likely or definitely contributory. RESULTS: Hypoactive delirium was associated with dementia, cerebrovascular and systemic infection aetiologies (p<0.001) and had a lower overall burden of delirium symptoms than the other motor subtypes. Hyperactive delirium was associated with younger age, drug withdrawal and the DEC category other systemic aetiologies (p<0.001). Mixed delirium showed the greatest symptom burden and was more often associated with drug intoxication and metabolic disturbance (p<0.001). All three delirium motor subtypes had similar levels of impairment in attention and visuospatial functioning but differed significantly when compared with no subtype (p<0.001). CONCLUSIONS: This study indicates a pattern of aetiology and symptomatology of delirium motor subtypes across a large international sample that had previously been lacking. It serves to improve our understanding of this complex condition and has implications in terms of early detection and management of delirium.

Delirium diagnostic and classification challenges in palliative care: subsyndromal delirium, comorbid delirium-dementia, and psychomotor subtypes.

CONTEXT: Delirium often presents difficult diagnostic and classification challenges in palliative care settings. OBJECTIVES: To review three major areas that create diagnostic and classification challenges in relation to delirium in palliative care: subsyndromal delirium (SSD), delirium in the context of comorbid dementia, and classification of psychomotor subtypes, and to identify knowledge gaps and research priorities in relation to these three areas of focus. METHODS: We combined multidisciplinary input from delirium researchers and knowledge users at an international delirium study planning meeting and relevant PubMed literature searches as the knowledge synthesis strategy in this review. RESULTS: We identified six (SSD), 33 (dementia), and 44 (psychomotor subtypes) articles of relevance in relation to the focus of our review. Recent literature data highlight the frequency and impact of SSD, the relevance of comorbid dementia, and the propensity for a hypoactive presentation of delirium in the palliative population. The differential diagnoses to consider are wide and include pain, fatigue, mood disturbance, psychoactive medication effects, and other causes for altered consciousness. CONCLUSION: Challenges in the diagnosis and classification of delirium in people with advanced disease are compounded by the generalized disturbance of central nervous system function that occurs in the seriously ill, often with comorbid illness, including dementia. Further research is needed to delineate the pathophysiological and clinical associations of these presentations and thus inform therapeutic strategies. The expanding aged population and growing focus on dementia care in palliative care highlight the need to conduct this research.