Charities and experts are warning that the number of patients who present themselves with everyday ailments but are also suffering from conditions such as Alzheimer's disease will rise "exponentially" as the population ages.
At the 900-bed ERI, 20 per cent of patients on any given day will be suffering from dementia, putting an enormous strain on both resources and nurses.
The worsening situation has led to calls to act now to prevent what some nurses are already describing as a "crisis" in care.
A report released yesterday for England and Wales showed that half of dementia patients admitted to hospital left in a worse state than when they went in.
Alzheimer's Scotland said the position was identical this side of the Border, and more had to be done to improve care.
Relatives of patients have told the Evening News that they feel dementia patients often miss out on key services such as physiotherapy straight after surgery.
Dr Alasdair MacLullich, who works at the ERI and is a senior lecturer at Edinburgh University's school of clinical sciences and community health, said: "In the ERI at any one time 20 per cent of the patients have dementia, and that is for an acute hospital, which is incredible.
"We would never stop someone from having physiotherapy just because they had dementia.
"What does happen is if someone lives in a nursing home they are discharged sooner because they are going to an increased care environment, and it could be that physio begins there with trained staff.
"The point about the training of physios is an interesting one. We are aware that extra skills are required to do what we can.
"Some have developed these but more research is needed to enhance the training coming through. The number of (dementia] patients we are dealing with is so large."
It is estimated by the local health board that there are 9,000 people with dementia in the area, though "many of these will not be diagnosed or known to services".
Peter Lerpiniere, a dementia nurse specialist with Alzheimer's Scotland, said: "It is a real challenge to manage and I don't think we are doing it particularly well at the moment, but we are trying to do something about that.
"It requires a person-centred approach because everyone who has dementia is different.
"People are being let down. If someone who requires physio cannot remember the exercises then they should be walked through them every time by a nurse.
"I think as a society, not just the health services, we forget the small things.
"Sometimes you will go into a care home or a hospital for elderly people and the dementia patients in there won't have seen the sky for some time.
"We focus so much on a safe discharge from hospital, which is right, perhaps we forget simple qualities of life, even something like walking in a park.
"We need to manage dementia better, and there's no excuse not to, we've managed it with other conditions in previous years.
"If we keep going the way we are we will have a real crisis coming down the track.
"We have to change our practice to improve outcomes because we are not doing as good a job as we should be."
NHS Lothian medical director Dr Charles Swainson refuted suggestions that nurses would choose not to help a patient because they had dementia. "NHS Lothian does not discriminate on any grounds and prescribes care according to individual need," he said.
"A quarter of the patients we treat with a hip fracture have some degree of dementia or Alzheimer's disease.
"It is incorrect to say that our team of highly trained physio-therapists are not equipped with the skills to work with patients with the condition.
"Some patients already receive physiotherapy in hospital, while others will receive rehabilitation in their home."
NHS Lothian is one of three areas in Scotland taking part in the Facing Dementia Together strategy, and it does have a specialist dementia nurse, unlike some other health boards.
As part of the scheme, it hopes to increase the number of people with dementia on its books, thus reducing those who are languishing without care or support in the community.
'Dorothy didn't get care as others would'
THE only real pleasure Dorothy McIntosh got from life was walking around the tranquil grounds of her nursing home.
But now the 85-year-old Alzheimer's sufferer cannot even do that, after undergoing hip surgery.
She fell while at the Pentlands Nursing Home and was rushed to the ERI.
Her husband Jim, 90, who lives in Comiston, believes it was the refusal to instantly take his wife through physiotherapy which has left her "shuffling" along on a Zimmer frame.
He is campaigning for the better treatment of dementia patients who are admitted to hospital with physical ailments.
"The only pleasure she really got from life was walking around the grounds of the home," he said.
"Now that doesn't happen for her, and I feel that because she suffered from Alzheimer's, she didn't receive the care anyone else would have got. I feel like it's them saying 'they're going to die anyway, so what's the point in bothering with them'."
Mr McIntosh added: "There's nothing that can help her now, but I don't want anyone else's life to be ruined in this way."
NHS Lothian medical director Dr Charles Swainson said: "We have met with Mr McIntosh to address his concerns and explain the reasons why, in many cases, physiotherapy in a home environment, rather than in an unfamiliar hospital setting, can be more effective for a patient with Alzheimer's disease.
"In Mrs McIntosh's case, we wanted to ensure that her rehabilitation was as close to her home environment as possible to help aid a speedier recovery and help her regain her full range of movement.
"We are delighted Mrs McIntosh made such a good recovery."