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In April, clinicians and scientists from Europe and the United States gathered in the lush surroundings of Duke University, North Carolina for what was only the third ever international conference on delirium. Talk of highlights is superfluous in what was a rich and provocative programme of presentations and discussions.

Current diagnostic schema in delirium have developed from expert consensus more than empirical work, and thus studies on delirium phenomenology are essential to address this. David Meagher (Limerick) presented research showing that inattention and poor comprehension appear to be essential, core parts of delirium. However, there is still much work to be done, for example in determining if inattention in delirium fluctuates as much as, say, psychotic features. This work will help to inform the evolution of better diagnostic criteria in DSM and ICD. Barbro Robertsson (Molndal, Sweden) surveyed the expanding range of instruments for delirium detection and severity assessment.. Paula Trzepacz (Indianopolis) and Madan Kwatra (Duke University) summarised work on the pathophysiology of delirium, including ongoing work using DNA microarray technology to examine gene expression in relation to post-operative delirium. The sum of evidence continues to implicate cholinergic dysfunction as an important contributory factor, but again this is an under-researched area.

Ed Marcantonio (Harvard) described the seminal work that he and Sharon Inouye have done showing that a model taking into account interactions among predisposing and precipitating risk factors provides the best current method of predicting delirium in medical and surgical patients. Dr Marcantonio also summarised the trials showing that delirium can, to some extent, be prevented by targetted, high-quality clinical geriatric care. Based on this research, programmes for delirium prevention are now being implemented in hundreds of hospitals across the United States. Kees Kalisvaart (Alkmaar, The Netherlands) presented his recently-completed clinical trial of low dose haloperidol prophylaxis in older patients undergoing hip surgery. With 430 patients randomised, this is currently the largest controlled drug trial of delirium in the literature. Although haloperidol did not reduce the incidence of delirium, it did reduce the severity and duration of delirium, with no serious side effects. There was broad acceptance that this trial is an important step forward in delirium research and practice.

Wes Ely (Vanderbilt) presented his work on the very high rates of delirium in intensive care units, and also worrying evidence that delirium in this and other contexts is strongly associated with poor adverse outcomes, including permanent decrements in cognitive ability. Bill Breitbart (New York) and James Fann (Seattle) covered developments in the diagnosis and treatment of delirium in palliative care settings; this provoked an interesting debate amongst the psychiatrists and geriatricians regarding the relative merits of antipsychotic drug treatments for delirium in older populations.

In this group of like-minded individuals there was no debate, however, on the urgent need for better clinical care and more research on what is now the single most common acute disorder in general hospitals. There was also the recognition that interest in delirium in geriatric medicine, psychiatry, and in medicine and nursing in general, is growing rapidly.

Alasdair MacLullich
MRC Clinican Scientist Fellow/Hon Consultant Geriatrician, University of Edinburgh