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Delirium OR Dementia?

It is important to be able to differentiate between Delirium and Dementia, especially in the senior population.

Dementia and delirium are particularly difficult to distinguish, and a person may have both. In fact, delirium frequently occurs in people with dementia. But having episodes of delirium does not always mean a person has dementia. So, ideally a dementia assessment should not be done during a delirium episode because the results could be misleading.

Because the symptoms of delirium and dementia can be similar, input from a family member or caregiver may be important for a doctor to make an accurate diagnosis. Also, in order to make a diagnosis of dementia, delirium must be ruled out by a physician.

Yesterday, I went to a hospital to visit a friend's father who is recovering from heart surgery. I was answering the family's questions until I hit a roadblock. They asked me if his confusion was an exacerbation of his dementia, which was diagnosed two years ago. I didn't know the answer to that. So, I started a conversation on the differences between dementia and delirium, which seemed to relieve the family. This incident made me realise how important it is to differentiate between the two. So, today's blog is dedicated to my friend's dad. Mr. E.S, Thank you for inspiring me.

Delirium is common, but it is under-diagnosed. The Alzheimer's Society says that "It is known that 20% of older adults in hospital have delirium. Among people with dementia in hospital, this figure is much higher". Delirium also develops in many people in nursing homes, long term care homes and a few in their own homes. 

It is not always clear why a person gets delirium. It is usually the brain’s reaction to an underlying medical problem. This could be an infection, such as pneumonia or a urinary tract infection. Delirium can also be caused by severe illness, surgery, dehydration, poor nutrition or a change in medication or medication dosage. 

Anyone can get delirium, but the following factors put people at higher risk:

- having dementia

- age over 65

- being frail or having multiple medical conditions

- having poor hearing or vision

- being on multiple medications

Dementia is the strongest risk factor for delirium, and the risk of getting delirium rises as a person’s dementia progresses. This is probably because the brain of a person with dementia is much more vulnerable to infections and other causes of delirium. 

To further distinguish between dementia and delirium, here's a table from a chapter in the Merck Manual (a guide for healthcare professionals):

If a relative, friend or someone in your care shows any signs or symptoms of delirium, see a doctor. Your input about the person's behaviour, thought processes and ability to perform activities of daily living will be important for a proper diagnosis and for finding the underlying cause.

If you notice signs of delirium in a person at a hospital or nursing home, report your concerns to the nursing staff rather than assuming that those problems have been observed. Older people recovering in the hospital or living in a long-term care facility are particularly at risk of delirium.

Living with dementia or caring for a loved one with dementia or delirium can be challenging. At in4MED, we can make this stressful time easier by providing you with information about your diagnosis, connecting you to local support systems and being there for you as your trusted health advocates. As always, feel free to connect with me or leave a comment.


Healthcare Consultant, in4MED


Dementia and delirium

Delirium or dementia?


The author of this blog post is a Physician with over 10 years of experience working in the healthcare system as a clinician, researcher and educator. She is passionate about healthcare for older adults and strives to be a resourceful inspiration to caregivers.

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