3. Dementia as a terminal illness
Dementia shortens life expectancy, but it is very difficult to know how long someone with dementia will live for. If the person also has another life-limiting illness, their condition is likely to worsen in a more predictable way over a period of weeks or days. This may mean that the person dies from another condition (eg cancer) when their dementia is at a relatively early stage.
But someone with later-stage dementia without another life-limiting illness often deteriorates slowly over many months. They gradually become more frail, have more frequent falls or infections, become less mobile, sleep more, and eat and talk less.
A person with later-stage dementia may have symptoms that suggest that they are close to death, but actually live with these symptoms for many months. This uncertainty makes planning for the end of someone's life difficult.
For someone with later-stage dementia, the most common immediate cause of death is an infection such as pneumonia. There are changes when the person is within a few days or hours of dying (see 'Recognising when someone is reaching the end of life' below). Families often find these changes distressing. Healthcare staff can help to reassure relatives that the person is not suffering.