Learn What Delirium Is—You Could Save Someone's Life

Delirium or dementia? The difference is important.

Posted Feb 24, 2013

Let’s start this blog entry with a story. A woman in her eighties lives alone (her husband died two years earlier). A friend phones her and is alarmed that whereas two days ago the old lady was fine, now she is incoherent and rambling. The doctor is called out and the woman is admitted to hospital with a diagnosis of a urinary tract infection. The woman continues to be delusional, convinced that her husband is still alive. In addition, she is hallucinating that there are puppies playing on her bed.

Hands up all of you who thought that this woman has got dementia? Old, not making much sense, seeing and imagining things: this is dementia, right? Well, actually, it’s not, and you could be making a potentially lethal mistake if you think it is.  What the woman is suffering from is delirium, otherwise known as acute confusional state.

Delirium can superficially appear the same as dementia, particularly if you have not met many people with dementia. However, there are differences. The main giveaway is that delirium has a very rapid onset. In the above example, the old lady went from normal to incoherent in two days – quite simply, there is no dementia that will cause such a rapid deterioration. Again, hallucinations (sensing things that are not really there) are relatively rare in dementia and likewise delusions (serious misunderstandings of reality) are not all that common in the earlier stages of dementia either.

Delirium can be brought on by many things – e.g. infections of the respiratory and urinary tract are amongst the commonest; a high temperature, dehydration, malnutrition are also well-documented factors.  Changes in drug treatments (new medication or sudden withdrawal from old medication) also are well-documented causes. If you look at hospital admissions, an adult being admitted because they are tripping out as a result of drugs is far more likely to be old than young.

Delirium is not unique to old age – it can affect younger adults and children. For example, I was physically fit, in my thirties, and tripped out on some (I must stress legally prescribed) drugs given me by my doctor for a torn back muscle. I hallucinated the monster from Alien, who sat on the edge of my bed, holding a bunch of flowers.  I had always hoped that in such circumstances, I would get Catherine Deneuve in (at most) a dishabille state, but such is life. 

However, delirium is far more likely to strike in people past their sixties. This is because older adults are generally weaker and infections/temperature rises can have more severe effects than in relatively robust younger adults (having significantly greater sensory impairment does not help matters either).

There is good and bad news about delirium. The good is that if the underlying cause of the infection, the raised temperature, etc, can be dealt with, then in the majority of the cases, the symptoms should go away.  The bad is rather less cheerful.

First, and most obviously, it is vital that delirium is detected so that the underlying cause can be dealt with. Without this treatment, the patient can all too easily die. So symptoms of delirium should never be discounted as being dementia or growing old. Great care is required to ensure that an infection is not overlooked. This is especially true in people who already have dementia – signs of delirium can be very easily dismissed as being nothing more than the person’s dementia being particularly florid.

Second, although in the main delirium disappears with the successful treatment of the cause, in a relatively small proportion of cases, the delirium doesn’t go away, but hangs around, waxing and waning in strength but settling down for a long (even rest of life long) stay.

Third, long-term delirium can co-exist with dementia. It is now recognised that dementia and delirium can be present in the same patient, leading to a far more complex clinical picture. I propose to return to this in a later blog. However, for my next blog I propose to look at something rather more jolly – namely, the use of language in people with Autism Spectrum Disorder.