What are the Main Differences Between Dementia VS Delirium?

Both delirium and dementia can be confusing to onlookers, yet in some ways the two conditions can mirror or mimic each other. Furthermore, it’s very common for those with dementia to develop delirium if they become unwell, confusing the matter further. This is difficult for many reasons and can prevent the sufferer from getting the right support and help. Here we look at dementia vs delirium and explain the main differences so that you can understand and interpret the symptoms.

Dementia vs delirium: causes of cognitive impairment

Both dementia and delirium are types of cognitive impairment – the most common ones you are likely to see in older people. This means that they affect thought processes and the way a person understands and interacts with the world around them. When considering dementia vs delirium, it’s important to remember that both cause disordered cognition and this can make them difficult to tell apart.

What is dementia?

Dementia is a general term for a group of conditions which impair cognition, mainly in terms of memory. Alzheimer’s disease is the most common type of dementia. Dementia is considered to be progressive and will ultimately significantly impair someone’s ability to manage daily activities. Unfortunately, there is no cure for dementia.

What is delirium?

Delirium, which is sometimes called ‘acute confusional state’, is also a cognitive impairment but mainly affects attention, causing confusion, rather than memory issues. It typically occurs as a result of someone becoming medically unwell. It can have numerous causes from infections to medications. Delirium can usually be solved by treating the cause or removing the trigger.

It is relatively common for delirium to develop in people living with dementia, making it quite difficult to spot without an experienced eye. It’s therefore quite often that delirium in dementia patients is overlooked and almost discarded as part of dementia when in fact it is a distinct condition that can be treated. There is no clear cut test to determine delirium which can make things more difficult, so it’s important to understand dementia vs delirium in presentation taking into account history and current condition.

Dementia vs delirium: the main differences

So, how can you work out if someone is experiencing delirium or their cognitive difficulties are part of their existing dementia, or yet to be diagnosed dementia?

There are some distinct differences when looking at dementia vs delirium:

Attention vs memory

While both delirium and dementia are types of cognitive impairment and can present with similar symptoms as a result, delirium is characterised by core problems with attention and dementia is characterised by core problems with memory. Both cause confusion, but the driving factor is markedly different. With delirium, the person is typically highly distracted or inattentive. They may even experience hallucinations or delusions which are not usually characteristic of dementia.

Chronic vs acute

Dementia can be described as a chronic disease. This means that it is long-term and ongoing. It’s also progressive and leads to deterioration over time. It is caused by (usually) irreversible changes in the brain. Conversely, delirium is most usually an acute condition meaning that it is short-lived. It’s not associated with permanent changes in the brain so when it is treated (or the cause of it removed), it disappears too.

Speed of onset

Dementia symptoms become apparent gradually, over time. Mild memory issues begin to become more significant. There is usually a very gradual decline (although speed of decline can vary) and the condition is identified over months or years. Delirium, on the other hand, tends to start very abruptly, often over days or even hours.

Reversible vs irreversible

Unfortunately, while research abounds, dementia is still irreversible (although some symptoms can be treated, managed and even improved, in some situations). Delirium can usually be completely reversed. When drug toxicity is solved, or the acute illness causing the delirium, such as a Urinary Tract Infection (UTI) is treated, the delirium goes away of its own accord.

What causes delirium?

Delirium is caused by specific things and rectifying these rectifies the delirium. Many of the causes may mean that there is an immediate health risk, so it’s important to identify these issues and seek immediate medical help. Therefore, if delirium is considered then it’s important to know what sort of things you may be looking for that can cause this cognitive state. The common causes of delirium include:

  • Infections: Infections in older people are a common cause of delirium. UTIs are a significant risk factor for delirium. When the infection is treated, the delirium will lift quickly.
  • Drug interactions, toxicity or sensitivity: It’s common for many older people to be on long-term medications. Sometimes these medications can trigger delirium, for example benzodiazepines. Delirium may not happen when someone first starts using a medication but may be the result of long-term use. Stopping the medication and using an alternative will rapidly remove the delirium.
  • Dehydration: Dehydration is a simple and common cause of delirium in older people, especially in those with dementia who may not remember to drink adequate amounts. Additionally, older people may be fearful of drinking enough because of incontinence concerns. When the person is hydrated, the delirium will lift. Preventing dehydration in those with dementia is essential for their wellbeing.
  • Kidney or liver failure: Delirium may be associated with kidney or liver failure and this should be considered by medical teams.
  • Other causes: There are other physical problems that may lead to delirium including head trauma or brain tumours. These are less common, especially in people with a dementia diagnosis.

The important factor behind all of these causes is that when the cause is removed, the delirium typically lifts extremely quickly.

The risk of overlooking delirium in people with dementia

As stated, delirium happens as a result of something else happening within the body. As such, it is like a warning signal that something else is going on. Usually, whatever the cause or trigger of delirium is, can be rectified relatively easily, especially when treated early.

Unfortunately, because delirium can be harder to spot in people living with dementia, the underlying cause may become worse and cause more damage, or become harder to treat. If you have spotted behavioural changes in a loved one with dementia which may indicate delirium, it’s important to seek medical advice urgently.

Dementia vs delirium is always an essential consideration and one which those responsible for the care of those with dementia need to take seriously. Spotting the signs of delirium should be par for the course for experienced care home staff. It’s one of the many reasons why expert dementia care is best for your loved one.

Visit our care homes in North Devon and Somerset to see what excellent dementia care looks like.