What is delirium?

Delirium is a severe state of confusion that happens as a result of being very sick. It is a very common condition for sick patients in the hospital and especially for those who have had a stay in the Intensive Care Unit (ICU). Older patients (over 65 years) are at highest risk for developing delirium. Some patients become agitated, while others may be quietly confused. Delirium is different from dementia because it develops suddenly, over hours to days, rather than months to years. And unlike dementia, delirium is usually temporary, resolving when the underlying cause is fixed. 

People with delirium:

  • Cannot think clearly
  • Have trouble paying attention
  • Have a hard time understanding what is going on around them
  • May see or hear things that are not there. These things seem very real to them

Delirium may also get better and worse in the day/night. Delirium is not a disease, but rather a group of symptoms. These symptoms generally fluctuate. In some patients, it may last longer and (usually) this happens with patients who have been very unwell and who have been given sedatives (medications to keep asleep) whilst on a mechanical ventilator (breathing machine). 

There are two main types of delirium. The first type of delirium is called hyperactive delirium, and often results in great agitation. Patients may try to get out of bed and pull at tubes and drips. This type of delirium often makes patients appear very frightened or distressed. They also may be very fearful of the doctors and nurses around them (and maybe suffering from some paranoia). 

The second type of delirium is called hypoactive delirium, and is very common. This type of delirium presents slightly differently in that the patient may appear calm, or just very sleepy and not wanting to talk or interact. However, often patients feel very muddled and unable to think clearly or concentrate on simple tasks. 

There can also be a mix of the two types. 

Watch the video telling you all about delirium:

Causes of Delirium

It is not clear why or how delirium develops. It is often thought of as a result of the “brain being sick” as a reaction to illness. There are many potential causes. In particular, the following illnesses have been found to make patients much more likely to develop delirium: 

  • Severe acute illness, such as a urine infection or chest infection 
  • Blood infection called “sepsis” from a severe infection
  • Stroke or a direct blow to the brain
  • Withdrawal from stopping daily alcohol use or smoking cigarettes 
  • Severe, uncontrolled pain
  • Broken hip
  • Post heart surgery
  • Known diagnosis of dementia

How delirium is diagnosed and how common is it?

We know that patients who have been in ICU and on a breathing machine are also likely to develop delirium in addition to the above conditions. Delirium is very common. 2 out of 3 patients in ICUs get delirium, and approximately 7 out of 10 patients get delirium whilst they are on a breathing machine.

Delirium may be difficult to recognize because changes in behaviour may be attributed to the patient’s age, history of dementia, or other mental disorders. In addition, the symptoms can come and go, such that a patient has no or few symptoms early in the day, but progressively worsens late in the day or in the evening.

If a caregiver or family member suspects that their relative has delirium, it is important that the patient is evaluated promptly to identify the underlying cause and begin treatment if possible.

Watch the video on the experience of having delirium:

What the Intensive Care community is doing about delirium?

The ICU community all over the world recognises how terrible delirium is for patients and their families. A tool called the “Confusion-Assessment-Method for the ICU” (CAM-ICU) is used commonly by doctors and nurses to assess ICU patients for delirium. The patient may remember the nurses and doctors asking questions and commands such as squeeze hands, poke tongue out, wiggle toes etc.

There is also a lot of attention paid in recent years to doing research in this area to understand more about this condition. Some of the research is around the following areas:

  • Why delirium happens and which patients are more at risk for delirium
  • What treatments and other things may help (such as early mobilisation and sunlight exposure)
  • How we can make the ICU stay better for ICU patients and families
  • How we can help patients sleep better at night whilst in the ICU
  • What medications may help reduce or prevent delirium (and which don’t)

What happens now?

Delirium can be frightening for the patient, as well as for the caregiver or family. Some patients are very worried about how delirium changes their ability to think clearly and howfast they can get back to normal life after recovery from illness. There may be effects that last for weeks to months. Some of these may be: 

  • Difficulty with concentration 
  • Finding the right words
  • Making their thoughts clear
  • Difficulty working through information and making sense of it

Caregivers may feel exhausted and frustrated because of the time and other resources required to take care of a person with delirium. Delirium can sometimes resolve within hours to days. In other cases, it takes weeks or months to fully resolve. For this reason, it is important for caregivers to discuss the patient's short- and long-term needs with a health care provider.

There may also be some anxiety or depression following an admission to ICU. These are very normal reactions to being so unwell. Hence, it is important to take time to see and talk with the medical team or GP about any of these feelings as they will be able to help with this. 

Further information that may help

  1. Critical illness, brain dysfunction and survivorship centre

Skip to content