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Subject 101: Delirium


Delirium is a neuropsychiatric disorder that frequently occurs in a hospitalized setting. Despite this, it is often misdiagnosed or not recognized and as a result not treated properly which could have serious consequences for a patient’s health. Due to this fact, I would like to dedicate this Subject 101 to delirium by presenting an overview of the essence of this acute confusional state.

There are different kinds of delirium, but they all have the same key symptoms of an acute onset of disturbance of consciousness and a global disturbance of cognition (e.g. disorientation, memory impairment), which can fluctuate in severity during the day. The hyperactive delirium is the most known and recognizable type. It can be generally characterized by psychomotor hyperactivity, agitation/aggression, hallucinations and delusions. The less known type, hypoactive delirium, is also the type that is often misdiagnosed as a dementia or depression and it is more prevalent than the hyperactive type. Its symptoms can involve apathy, withdrawn behavior and decreased alertness. The best way to differentiate between the three disorders is that dementia or depression are not associated with a disturbance of consciousness. Furthermore, a delirium emerges acutely in a matter of hours or days while a depression and dementia takes weeks, months or even longer to develop.

The final type is a mix of the two previous types, where patients fluctuate between a hyper- and hypoactive state. Of these three types, the pure hyperactive delirium is quite rare.[1-5]

The prevalence among elderly patients in a hospital, a high risk group, can be as high as 30-40%.  Delirium is associated with prolonged hospitalization, an increased chance of complications and mortality. It can bring previously unrecognized cognitive impairment to medical attention and there is growing evidence that delirium itself might lead to permanent cognitive decline and dementia. It is imperative to obtain a heteroanamnesis to assess the premorbid cognitive function of the patient and to exclude an alcohol withdrawal delirium, for which the primary treatment are benzodiazepines. The confusion assessment method (CAM) is a quick tool that can be useful when diagnosing a delirium (sensitivity 94%, specificity 89%). The Delirium Observation Screening scale (DOS) is often used by nurses to monitor the patient’s symptoms every shift.

It is good to realize that a delirium is mostly caused by a combination of predisposing factors like age and premorbid dementia or other cognitive disorders, and precipitating factors like a somatic disease or certain medication usage.  What it basically comes down to is if the patient is very vulnerable (multiple predisposing factors), it doesn’t take many precipitating factors to cause a delirium. [1-5]

The best treatment for delirium is to treat the underlying cause, whether it is an infection, electrolyte disturbance or something else. Nonpharmacological interventions aimed to, for example, increase the patient’s orientation or restoring the sleep-wake cycle are required as well. In some cases, mostly for hyperactive delirium where it is necessary to manage symptoms like agitation and combative behavior, antipsychotics like haloperidol, olanzapine and quetiapine are indicated to protect the patient’s health. Antipsychotics cannot cure a delirium, the treatment is purely symptomatic. They are not indicated for hypoactive delirium.  Unfortunately, there is a limited amount of randomized controlled trials that have evaluated the effect of antipsychotics. However, the limited data that exists does support their use and so far there are no known alternatives for managing delirium pharmacologically.[1-5]

In conclusion, delirium frequently occurs in hospitalized, mostly elderly, patients. It could lead to prolonged hospitalization or even permanent cognitive decline. It is essential to find the underlying precipitating cause and treat it, as antipsychotics can manage the symptoms but not cure the delirium.

A. van Aken & P.P. de Koning


  1. Guideline delirium adults and eldery people, NVvP (Dutch Association for Psychiatry)
  2. K. Inouye, R.G.J. Westendorp, J.S. Saczynski et al. Delirium in elderly people Lancet. 2014 Mar 8; 383(9920): 911–922
  3. W. Hengeveld, A.J.L.M. van Balkom Leerboek psychiatrie. De tijdstroom. 2009, 2nd edition
  4. Guideline delirium VUmc
  5. Website Up To Date, Available here

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